A List of identified variables

Variable stars in the open cluster NGC 6791 and its surrounding field

Key Words.:
Stars: starspots – Stars: statistics – Stars: variables: general – binaries: eclipsing – novae, cataclysmic variables – open clusters and associations: individual: NGC 6791
1

Abstract

Context:

Aims:This work presents a high–precision variability survey in the field of the old, super metal–rich open cluster NGC 6791.

Methods:The data sample consists of more than 75,000 high–precision CCD time series measurements in the band obtained mainly at the Canada–France–Hawaii Telescope, with additional data from S. Pedro Mártir and Loiano observatories, over a time span of ten nights. The field covers an area of arcmin.

Results:We have discovered 260 new variables and re-determined periods and amplitudes of 70 known variable stars. By means of a photometric evaluation of the membership in NGC 6791, and a preliminary membership based on the proper motions, we give a full description of the variable content of the cluster and surrounding field in the range 16  23.5. Accurate periods can be given for the variables with  4.0 d, while for ones with longer periods the limited time–baseline hampered precise determinations. We categorized the entire sample as follows: 6 pulsating, 3 irregular, 3 cataclysmic, 89 rotational variables and 61 eclipsing systems; moreover, we detected 168 candidate variables for which we cannot give a variability class since their periods are much longer than our time baseline.

Conclusions:On the basis of photometric considerations, and of the positions of the stars with respect to the center of the cluster, we inferred that 11 new variable stars are likely members of the cluster, for 22 stars the membership is doubtful and 137 are likely non–members. We also detected an outburst of about 3 mag in the light curve of a very faint blue star belonging to the cluster and we suggest that this star could be a new U Gem (dwarf nova) cataclysmic variable.

Authors Nr. of variables IDs Notes
Kaluzny & Rucinski ((1993)) (KR93) 17 V1–V17 V15B7
Rucinski, Kaluzny & Hilditch ((1996)) (RK96) 5 V18–V21 and B8
Mochejska et al. ((2002)) (M02) 47 V22–V67 and B4 B4 was previously catalogued by
Kaluzny & Udalski ((1992)) as
a blue star, but not as variable.
Mochejska et al. ((2003)) (M03) 7 V68–V74
Kaluzny ((2003)) (K03) 4 V75–V78
Bruntt et al. ((2003)) (B03) 19 V79–V100 V85V76; V56V96; V77V88
Mochejska et al. ((2005)) (M05) 14 V101–V114
Hartman et al. ((2005)) 10 V115–V124 Plus 7 suspected variables
Table 1: Previous variable star searches in NGC 6791.

1 Introduction

The photometric precision achieved by several ongoing transiting planet searches allows us to extend the census of variable stars down to very low amplitudes and faint magnitudes in selected sky regions. Variable stars are an important source of astrophysical information: from observations of them we are able to test several theories (e.g., evolutionary and pulsational models). Since all stars in an open cluster have essentially the same age, chemical composition and distance, the study of variables which are cluster members can put more severe constraints on the physical parameters. Comparisons can also be made between the variable stars of the cluster and those of the surrounding field.

In this paper, we present the study and the classification of 260 new variable stars that we found in the field of the open cluster NGC 6791, while for 70 already known variables we compare our results with the previous ones. NGC 6791 (= 19 20 53; = +37 46′18″), is a rich and well studied open cluster. It is thought to be the one of the oldest and probably the most metal-rich cluster known in our Galaxy. Its age is estimated to be about 8–9 Gyrs (Carraro et al., (2006); King et al., (2005); Chaboyer, Green, & Liebert, (1999); Stetson et al., (2003); Kaluzny & Rucinski, (1995)); however, the white dwarf cooling sequence indicates a different value, i.e., 2.4 Gyr (Bedin et al., (2005)). The most recent estimates of its metallicity are [Fe/H]=+0.39 (Carraro et al., (2006)), [Fe/H]=+0.47 (Gratton et al., (2006)), and [Fe/H]=+0.45 (Anthony-Twarog et al., (2006)). In this work we adopt for NGC 6791 a distance modulus mag and a reddening =0.09 mag (Carraro et al., (2006)). The cluster is thus located at about 4.1 kpc from the Sun.

Because of its extreme characteristics, NGC 6791 has been the target of many surveys (see Table 1 for a list of publications). Taking into account the fact that in four cases the same stars have two identification numbers (V15B7, V56V96, V76V85 and V77V88) and counting also the stars B4 and B8, the total number of known variable stars in the field of NGC 6791 to date was 123 (plus 7 suspected variables, proposed by Hartman et al., (2005)).

In Sect. 2 below we describe our observations, in Sect. 3 we give details about the methods we employed in the search for variable stars, which are themselves presented in Sect. 3.2. In Sect. 4 we describe the properties of the variable stars, focusing our attention on probable cluster members and some additional peculiar cases. The entire catalogue of variable stars is reported in an Appendix.

2 Observations and data reduction

We surveyed NGC 6791 to detect the transits of extrasolar planets (Montalto et al., (2007)). The campaign covered 10 consecutive nights (from July 4, 2002 to July 13, 2002) and it was characterized by the continuous monitoring of the target on each clear night. Therefore, in addition to the planetary transit search, we could get access to the full variability content at  4.0 d, both for the cluster and the surrounding field. Three telescopes were used:

  1. The Canada–France–Hawaii Telescope (CFHT) in Hawaii equipped with the CFHT12k detector, composed of 12 CCDs of 4128 2048 pixels and covering a field of about 0.32 deg. Owing to the large number of bad columns, data from chip 6 could not be used, so we could get data over a 0.29 deg field;

  2. The San San Pedro Mártir (SPM) 2.1–m telescope equipped with the Thomson 2k detector and covering a field of about  arcmin;

  3. The Loiano 1.5–m telescope equipped with BFOSC + the EEV 13001348B detector and covering a field of  arcmin.

Table 2 gives details about the length of the observing nights while Figure 1 shows the field of the CFHT survey and the edges of the Loiano and SPM surveys. The coordinates of the edges of our fields are also listed in Tab. 2. The field of the SPM observations is entirely included within chip 9 and the field of the Loiano observations partially covers chips 2, 3, 4, 8, 9 and 10 of CFHT (see Fig. 1). The luminosities of the new variables range from =23.2 mag to  mag (near 1 mag above the turn–off); brighter stars are saturated. The calibration of the CFHT, Loiano and SPM data have been performed by using the Kaluzny & Rucinski photometry ((1995)). More details on the data reduction procedure can be found in Montalto et al. ((2007)).

Loiano SPM CFHT
Night t t t
(HJD–2452400) (HJD–2452400) (HJD–2452400)
1 59.82 59.96
2 60.83 61.02
3 62.48 62.63 61.68 61.95 61.94 62.07
4 63.41 63.63 62.68 62.96 62.76 63.07
5 64.38 64.64 63.68 63.96 63.88 64.10
6 65.39 65.62 64.69 64.98 64.77 65.11
7 65.70 65.82
8 66.69 66.97
9 67.67 67.98 67.77 68.10
10 68.69 68.87 68.76 69.11
19 20 258 19 20 363 19 19 237
19 21 304 19 21 104 19 22 580
37 41′226 37 43′154 37 36′67
37 53′427 37 50′31 38 4′212
Table 2: The observation log for each night and the limits of the field of view at the 3 different observatories.
Figure 1: Field of view (42 28 arcmin) of the CFHT image. The chips are numbered in increasing order from left to right from chip 1 (top left) to chip 12 (bottom right); stars of chip 6 are not plotted since we found it impossible to derive accurate photometry. Dashed and solid lines are the edges of the SPM and Loiano fields, respectively. Variable stars are also plotted: blue dots are pulsating variables, purple dots are irregular and cataclysmic variables, green dots and cyan dots are eclipsing systems (EA/EB–Type and EW–Type, respectively). Finally, red and yellow dots are rotational and long–period variables, respectively.

3 The identification of variable stars

The intensive monitoring of NGC 6791 allowed us to obtain tens of thousands of photometric time series for stars located in, close to, and far away from the cluster center. We have analysed 73331, 6055, and 2152 light curves obtained from the CFHT, Loiano and SPM telescopes respectively. The CFHT, Loiano and SPM time series are composed of about 250, 60 and 170 datapoints, respectively. The observations, intended to detect photometric transits, were performed in the band only.

3.1 The search for variable candidates

To search for variable stars, we calculated the best “sinusoid plus constant” fit for all light curves (Vanicek, (1971); Ferraz-Mello, (1981)). We evaluated the goodness of the fit by calculating parameters related to the reduction of the initial variance obtained by introducing the periodic term. These parameters are the reduction factor (Vanicek, (1971)) and the coefficient of spectral correlation (Ferraz-Mello, (1981)).

Owing to the huge number of light curves, we need one or more parameters to discover the variability. Toward this goal, we considered the parameter defined as , where is the maximum value of (i.e., the one corresponding to the frequency of the best-fit sinusoid in the Ferraz-Mello method). If a star does not show variability the introduction of a sinusoid does not improve the fit and then is close to zero (no variance reduction) and ; on the other hand, a sine-shaped variability strongly reduces the variance ( close to 1) and hence . The purpose was to use the parameter as a tracer of variability for short-period (i.e., intranight) variability.

To search for long–period variability, we introduced a second parameter, more sensitive to the night–to–night variations. We calculated the mean magnitude and the standard deviation on each night, and after that we calculated the parameter defined as:

where is the peak–to–peak difference and is the mean of the over all nights.

To test the capability of the and parameters to detect variable stars, we prepared a sample containing two types of light curves: 7722 artificial constant light curves (see Montalto et al., (2007) for details) and 70 light curves of already known variable stars which are included in our CFHT field. In Fig. 2 we plot vs. for the light curves of constant stars (small points) and of variable stars (large points). The variable stars are substantially apart from the constant stars and most have . The variable stars with and superposed on constant stars are mostly EA–type stars or irregular stars (e.g., cataclysmic variables). Among variables (i.e., large dots in Fig. 2), the stars with small have short periods ( d), while stars with large have long periods. Therefore, we can conclude that the combination of the and parameters is a good tracer of variability.

To detect the variable stars in our sample of 82,000 light curves we first selected in an automatic way all the stars with , according to the test described above. We thereby reduced the huge initial sample to 6,500 stars. After the calculation of the amplitude spectrum of their time series, we adopted as a second selection criterion a signal–to–noise ratio (S/N) greater than 4.0 around the highest peak in the amplitude spectrum. This procedure allowed us to reduce our sample to 900 stars, i.e., 1.1% of the whole initial sample. Further checks have been made by examining the light curves of a random sample of stars with , large and 3.5S/N4.0, but we did not find any additional variables.

Our approach allowed us to detected hundreds of stars showing peaks in their power spectra at 1.00 cd, at 0.05 cd, or at =0.6 cd. The first two spurious periodicities are common and can be ascribed to small misalignments in the mean magnitudes from one night to the next or recurrent drifts (caused by small color effects, for example) in the intranight light curves. We suggest that the latter one is probably a photometric artefact occurring in some particular cases of blended stars, or stars close to CCD edges, or bad pixels. They have been considered as not reliable enough to infer a physical light variability. In our opinion, only the combination of automatic procedures and visual inspection allowed us to identify the three classes (=1.00 d, =1.6 d, 10 d) of spurious variables in the huge number of 82,000 light curves. In particular, we note that the identification of the whole sample of eclipsing binaries has been confirmed by the application of the box fitting technique (BLS, Kòvacs et al. (2002)), used by Montalto et al. ((2007)) to detect planetary transits.

At the end of the variable star identification, we were left with 330 cases to be characterized. Since we rejected about 2/3 of the sample selected by means of the parameters, we are confident we have not applied overly strict constraints in the candidate selection.

3.2 The cross check with previous surveys of NGC 6791

Figure 2: Grey points: parameter vs. parameter for constant light curves. Black dots: parameters derived from our light curves for the variable stars previously detected in our field.

When comparing our field of view with those of other surveys, we found that 81 known variable stars are included. The CFHT survey failed to detect 45 known variable stars: seventeen stars (V22, V24, V26, V28, V30, V35, V36, V47, V50, V57, V61, V63, V64, V102, V103, V104, V105) are outside the CFHT field of view; 4 stars (V71, V106, V113 and V120) lie between two chips; 23 stars (V1, V6, V13, V19, V33, V39, V45, V49, V54, V56V96, V65, V66, V67, V69, V70, V72, V73, V74, V77V88, V78, V81, V97 and V112) are saturated; and the V76 data are useless.

Among the 81 known variable stars that we have observed, not all of them display variability in our sample: 4 stars (V10, V18, V21, V32) are previously classified as long-period detached eclipsing variables and we did not observed eclipses. We are not able to confirm the period of 15.24 days for V68 (M03), likely because of our shorter time baseline and the small amplitude of this variable (about 0.003 mag in –band, M03). Finally, we cannot confirm the variability of six stars (V20, V79, V84, V98, V99, V116) and of the seven suspected variables found by H05, since our data do not show any trace of variability.

Among the sample of the stars missing from the CFHT field, we identified 22 stars in the Loiano and SPM data sets (V6, V13, V19, V20, V33, V45, V54, V56V96, V65, V66, V67, V70, V71, V73, V74, V76V85, V77, V78, V81, V97, V106 and V113). However, owing to the smaller signal–to–noise ratio (S/N), the small number of datapoints and (in the case of the Loiano data) the limited survey time, we could only confirm the variability of stars V56V96, V66 and V76V85.

Throughout this paper we use the existing names for the already known variables; to identify the new ones discovered in our survey we used the five–digit number assigned by the DAOPHOT package followed by the number of the chip which the star belongs to. Accurate astrometry is provided to identify the stars on the sky. Moreover, all light curves of the variables will be available on CDS.

4 The variable star content of NGC 6791 and its surrounding field

Figure 3: Proper-motion vector-point diagram for the inner region of NGC 6791 (from Bedin et al., (2006)). The circle (centered on the absolute proper motion of the cluster) represents a safe limit corresponding to 0.5 mas/yr. Triangles represent non–members, points with error bars are the new variables 06289_9, 04803_9 and 09831_9

The CFHT measurements are quite precise, thus the light curves are generally very well defined for 4 d. On the other hand, the periods and the shapes are uncertain for 4 d, since the observations only covered 2.5 cycles or less. We refer to Montalto et al. ((2007)) for a full description of the photometric errors. In order to evaluate the precision in the study of the variable stars, we calculated the standard deviations of the Fourier least-squares fits (truncated at the last significant term for the given star) for the 138 light curves having very good phase coverage. The precision was found to be better than 0.010 mag in 73 cases (53%), and better than 0.020 mag in a total of 122 cases (88%), as expected for stars ranging from 16.0 to 22.5. The discussion based is mostly on the CFHT data, which are by far the most numerous, precise and homogeneous; however, for some variables we have used data from Loiano and SPM in a very profitable way. As an example, only the longitude spread of the three observatories allowed us to derive the periods of the eclipsing binaries 00645_10, V107, V12, V109 and of the rotational variable 03079_9.

To proceed in the definition of the variable star content of NGC 6791 and its surrounding field, we calculated the power spectra of the data for all the 330 candidate variables by using the least-squares iterative sine-wave search (Vanicek, (1971)) and the Phase Dispersion Minimization (Stellingwerf, (1978)) methods. Differences have been examined and resolved. The separation into different classes of variable stars has been made on the basis of the light curve parameters (period, amplitude, Fourier coefficients) and standard photometric values (, , ), when available. The period estimates have been refined by means of a least–squares procedure (MTRAP, Carpino (1987)) and appropriate error bars have also been calculated. At the end of the process we get six pulsating stars with  d, three irregular variables, three cataclysmic variables (CVs), 31 detached or semi–detached eclipsing binaries, 29 contact binaries, 90 rotational variables, 167 stars showing clear night-to-night variability on timescales too long for periods to be determined over our 9.2–d baseline. We adopt preliminary membership probabilities based on proper motion measurements kindly provided to us by K. Cudworth (private communication) for 35 stars. Moreover, for three new variable stars we adopted membership probabilities based on proper motions performed by Bedin et al. ((2006)) (hereafter B06, see Figure 3).

For the other stars, we consider their position in color–magnitude diagrams (CMDs), and their distance from the center of the cluster to infer whether they belong to the cluster (for EW–Type stars we also utilize the -- relation of Rucinski ((2003)). Toward this end, we plotted the radial distribution of all stars in Fig. 4. We see that at a distance of 10′  from the center of the cluster, the stellar density becomes near constant (about 21 star/arcmin). Thus, we adopt the value of 10′  as the external limit of the cluster and we consider “likely non-members” the variables located farther from the cluster center.

Figure 4: Stellar density (number of stars per square arcminute) as a function of the distance from the center. The straight line represents the mean stellar density at distances greater than 10′.

4.1 Pulsating variables

The main characteristics of our variables are listed in Tab. 3 and their light curves are shown in Fig. 5. The classification as High–Amplitude Delta Sct (HADS), SX Phe, RRc or RRab stars is based on the parameters of the Fourier decomposition (Poretti, (2001)). In all cases, the Fourier parameters are on the progressions described by the different classes. We note that our period for V123 is quite different from that given by H05 (0.107 d). Error bars on the periods are in the range 1–6 d.

Both RR Lyr variables are too faint to belong to NGC 6791. Since they have =17.21 (03653_3) and =18.28 (00345_1), their distance moduli greatly exceed that of the cluster.

This is also true for the very faint and short-period stars 00311_7 (=23.17) and 00224_10 (=21.72); therefore, it is more likely that they are Pop. II stars. On the other hand, using the relation given by McNamara ((2000)), we get distance moduli of 14.50 and 13.78, respectively, for V123 and 01497_12. These distance moduli and the distance from the cluster center (12′  and 22′, respectively) suggest that they do not belong to the cluster, though they are not very far from it. Therefore, they are probably Pop. I stars and hence High Amplitude  Scuti stars.

Moreover, there are several variables whose light curves are very similar to those of Cepheid variables; the Fourier decomposition of some light curves (in particular the large amplitude ones, i.e., 00913_5, 01659_8, V46 and 01431_10, but also 01606_11, 02285_10, 00122_4 and 03056_3) yields parameters typical for Cepheid light curves. However, most of these variables are quite faint and the Period–Luminosity relation for Cepheids (Tammann et al., (2003)) yields distances in the range 39-171 Kpc. It is difficult to say whether these stars are nearby rotational variables (see below) in the Milky Way or very distant pulsating variables. For our present purposes, these stars have been included among the rotational variables listed in the Appendix.

The puzzling nature of all these apparently distant stars (i.e., the Cepheid-like ones, the RR Lyr and the faint SX Phe variables discussed above) deserves further investigation by means of spectroscopic and/or kinematic data.

4.2 Irregular variables

Table 3 also lists three irregular variables: these stars lie on the middle Main Sequence and are all located less than 3′  from the cluster center; thus we suggest that they belong to the cluster. V92 and V83 were previously defined as “periodic variables” by B03. Indeed, we noticed fast variability in our light curves (Fig. 6), but, more noticeably, the mean magnitude is also changing from night to night. The long periods given by M03 are not able to explain either the short- or the longer-timescale variability; actually, we could not detect any periodic term. We also detected no trace of periodicity in V93 (Fig. 6); we suspect that the periods given by M05 and B03 are spurious, since they are close to 1.0 d (0.99 and 0.94 d, respectively) and they could be produced by the irregular fluctuations.

We can conjecture that these variables are eruptive variables observed in a quiescent phase, in which rapid and/or slow changes with smaller amplitude can be observed; they resemble the case of V15 (see Sect. 4.3). We have no reliable indications about the membership probabilities.

4.3 Cataclysmic variables

As regards V15: M03 and M05 detected variability over the range of 3 mag and observed outbursts of about 0.5-1.0 mag; from our side, we could see a 0.15–mag variability in our light curves (Fig. 6), corresponding to the quiescent phase. V15 is very probably a NGC 6971 member, since the Cudworth proper-motion membership probability is very high (98%).

Both the position of the faint blue star 06289_9 in the two-colour diagram and the shape of its light curve (Figure 7) strongly suggest that this star could be a new cataclysmic variable (U Gem-type, dwarf nova). Moreover, we know that this object is a cluster member (see Figure 3). The star shows an outburst of about 3 mag and, though we did not observe the entire brightening, we would highlight that the magnitude was still increasing on the first night; thus we are able to say that the maximum brightness was reached immediately after.

We can estimate the orbital period, , and the recurrence time, , from the decay time, = [days mag] and the amplitude, (Warner, (1995), equations 3.5, 3.1, respectively). Assuming for and the values 3.330.50 d and 2.870.31 mag respectively, we find =2.541.41 h and =13.910.6 d. However, our light curve (Fig. 7) seems to rule out values shorter than 8 d.

The variable B8 shows a large-amplitude light curve (Fig. 7) over a quite short 7 d time span. The cataclysmic nature of B8 has been confirmed spectroscopically by Kaluzny et al. ((1997)) who also notes that B8 exhibits red colour while in a low state.

Following the same procedure used for 06289_9 and assuming =1.30.3 d mag for B8, we find =2.971.63 h and =11.48.5 d. The value is compatible with the 7 d periodicity (Fig. 7). A membership probability is not available for B8. However, using the equations 3.3 and 3.4 after Warner ((1995)), we obtain =8.060.68 mag and =4.970.42 mag. In turn, these values give two estimates for the distance modulus of B8, i.e., 13.82  0.68 mag and 14.20  0.42 mag. We note that the first is in agreement with the distance modulus of the cluster. Kaluzny et al. ((1997)) assumed that B8 belongs to the cluster, finding =5.2 mag and =7.6, i.e., values very similar to ours. B8 is located at 4′ from the center, and we can only conclude that the membership of this star is very probable.

Star Type Ref. Period Ampl.
[mag] [mag] [mag] [HJD–2452400] [d] [mag]

Pulsating variables


V123
HADS 19.362064 37.666034 17.08 0.45 k 59.559 0.06026 0.14
01497_12 HADS 19.379083 37.812419 16.06 59.528 0.07227 0.40
00311_7 SXPhe 19.324628 37.716768 23.17 59.605 0.10443 0.10
00224_10 SXPhe 19.353639 37.710163 21.72 0.71 1.06 s 59.801 0.12261 0.20
03653_3 RRc 19.347147 37.992413 17.21 0.57 0.58 k 59.937 0.32654 0.39
00345_1 RRab 19.325082 37.964170 18.28 60.151 0.57866 0.72
Irregular variables


V92
IRR 19.350754 37.766876 18.10 0.91 k 0.10
V83 IRR 19.346220 37.737232 19.10 1.02 1.05 k 0.07
V93 IRR 19.351452 37.785687 18.12 0.98 1.03 s 0.04

Cataclysmic variables



V15(=B7)
CV 19.352057 37.799019 18.26 0.20 k 0.06
B8 CV 19.343262 37.747833 20.64 –0.23 0.78 k 2.27
06289_9 CV (?) 19.348976 37.770355 22.80 0.25 0.88 s 3.10


Table 3: Pulsating, irregular and cataclysmic variables. is the minimum brightness for CVs and irregular, the mean brightness for pulsating variables. is the time of maximum brightness for pulsating stars. Hereafter, the labels “k” and “s” indicate that the color index is taken from Kaluzny & Rucinski ((1995) or Stetson et al. ((2003)), respectively.
Figure 5: Light curves of pulsating variables. V123 and 01497_12 are probably HADS stars, 00311_7 and 00224_10 are SX Phe stars, 03653_3 and 00345_1 are RR Lyr stars.
Figure 6: Variable stars showing irregular fluctuations.
Figure 7: Top: Light curves of B8 (CV star) and 06289_9 (candidate CV). Bottom: positions in the two–colour diagram for two irregular stars (V83 and V93), for the cataclysmic variable B8 when in a low state, and for the new variable candidate 06289_9.

4.4 Contact binaries

Figure 8: The light curves of the contact binaries that are likely members of NGC 6791. The case of 01434_3 (amplitude much larger than 0.75 mag) is also shown in the last panel.
Figure 9: The values calculated for contact binaries by means of the Rucinski ((2003)) -- relation plotted against the distance from the cluster center. Triangles indicate the stars whose membership has been proposed by M03, the filled circles the stars whose membership has been proposed by us, and the open circles the stars that we suggest do not belong to NGC 6791. The starred point indicates the star 09891_9 which does not belong to the cluster on the basis of the proper motion (B06). The value for the cluster (solid line) with an error bar of 0.20 mag (dashed lines) is also shown.

The simplest cases of eclipsing systems are the contact binaries (also named W UMa systems); they show short periods and continuous variability and therefore can be easily recognized and classified. We detected 29 of these variable stars; they have 0.40 days and very well defined light curves. The complete list and the light curves are reported in the Appendix. Tab. LABEL:ewbel lists the stars likely belonging to NGC 6791 (see above); their light curves are shown in Fig. 8. The very short periods and the secondary minima occurring at indicate binaries with circular orbits, as is also the case for stars with small amplitudes (in 7 cases we have amplitudes less than 0.20 mag: V3, V4, V5, V8, V23, V40 and 01441_8). The average error bar on the period estimates is of the order of 4–5 d.

However, we note that the stellar surfaces are not homogeneous since the maxima are often at different heights. Therefore, binarity and activity are probably combined here. In particular, the shape of the light curves of V4 (comparing RK96, M02 and our data) and V7 (comparing K93 and our data) have changed a lot; we suppose that stellar spots strongly modify the light curves. Proximity effects are also responsible for the large amplitudes observed for 01434_3 (Fig. 8, last panel) and 00766_5. We also found different periods for V118 (0.306321 d) and V124 (0.320143 d) compared to H05.

As for membership, the probabilities provided by Cudworth are 78%, 98% and 98% for V3, V4 and V5, respectively. Indeed, they are very close to the cluster center (45, 21 and 28, respectively).

We suggest that 01441_8, V118, V8, V117 and V7 are also contact binaries belonging to NGC 6791. To further verify this hint, we calculated their distance by using the -- relation given by Rucinski ((2003)); they turn out to have distance moduli (13.28, 13.28, 13.48, 13.28 and 13.18, respectively) very similar to that of the cluster (13.35).

Moreover, these stars are located at similar angular distances from the cluster center (62, 72, 71, 72 and 63, respectively). Figure 9 shows how the distance modulus of the cluster is in better agreement with those of the stars we proposed as cluster members than with those of the previously known members. Their positions in the CMDs (Fig. 10, filled circles) are similar to those of stars in the sample with 7.5 whose parallaxes have been determinated by HIPPARCOS (Rucinski, (2003)). We also note that most of the cluster members are near the turnoff point.


Star
Ref. Period Ampl. Notes
[mag] [mag] [mag] [HJD–2452400] [d] [mag]



01441_8
19.339422 37.778118 19.98 1.38 k 63.073 0.24544 0.07 likely memb.
V118 19.347500 37.651222 17.68 0.75 1.01 s 59.912 0.30623 0.70 likely memb.
V5 19.346258 37.813354 17.19 0.90 0.95 k 60.221 0.31274 0.05 member (98%)
V3 19.354380 37.769349 18.51 1.05 1.06 k 59.798 0.31764 0.09 member (78%)
V4 19.348396 37.806652 17.72 1.01 k 59.591 0.32568 0.10 member (98%)
V8 19.341938 37.865810 17.81 0.79 0.88 k 59.896 0.33406 0.10 likely memb.
V117 19.343433 37.665848 17.66 0.87 0.90 k 59.987 0.36644 0.38 likely memb.
V7 19.340271 37.821892 17.63 0.93 0.86 k 59.820 0.39174 0.31 likely memb.

Table 4: Coordinates and light curve parameters of the contact binaries (W UMa systems, EW) belonging to NGC 6791. is the brightness at maximum and is the time of the primary minimum.

4.5 Eclipsing variables

In the cases of detached or semi–detached eclipsing binaries the classification and membership tasks are different from the case of contact binaries. Tab. LABEL:tabea lists the systems for which we could determine periods; their light curves are shown in Fig. 11. We still have short-period cases where we can reconstruct the complete light curve, as for the classical examples of Lyr variables (V29, 01558_5 and 00331_3). V9 is a more complicated Lyr system in which spots produce maxima with different heights. Indeed, it has been classified as an RS CVn variable by M05 and B03; they also observed a “shift of the modulation wave” from 1995 to 2002.

We note that our period for V119 is quite different from that given by H05 (0.1133 days); the new period makes this star an intermediate case between semi–detached and contact systems. Error bars on the periods in Tab. LABEL:tabea are  d for 1.0 d,  d for 2.0 d and a bit larger for 3.0 d.

Some variables show very sharp eclipses and out-of-eclipse variability due to different levels of stellar activity (05736_9, 00645_10, V109, 01393_1, V11 and V107; for the period of the latter star we prefer the longer of the two values given by M05).

In many cases we observed one eclipse only and we cannot give any value for the period, unless it has been given in the previous studies, as for the cluster member V80 (86% on the basis of the Cudworth membership probability). We also note that the amplitude we observed in V80 is much larger than that reported by B03.

To establish the membership of these eclipsing systems is not an easy task, since binary effects should be taken into account when considering colors and magnitudes. However, on the basis of the distance from the cluster center and their position in the CMDs, we can argue that V60, 02461_8 (both single-event eclipsing binaries), 05736_9, V29 and 00645_10 are very probable members. This hint is corroborated by the membership probabilities for V60 and 02461_8, which are 91% and 88% respectively.

The special cases of V9 and B4 deserve attention. V9 is the binary closest to the center and its membership probability is 82%. However, it looks a very evolved object in the CMD; its period (3.2 d) and activity (see above) are also more typical for a Main Sequence star. Therefore, its membership is very doubtful.

The Cudworth membership probability for B4 is only 40%, but in the CMDs B4 belongs to a little “clump” of very blue stars. This location is in agreement with the results of Liebert et al. ((1994)) and therefore B4 is likely a blue extanded horizontal–branch star belonging to NGC 6791. The star is classified by M02 and M03 (who consider it a non–member) as an eclipsing binary, but we note that the light curve could also result from a rotational modulation.

Other possible members are: V107, 00331_3, V109 and V11, considering that they are within 64 radius from the cluster center. The location in the CMDs of the eclipsing binaries belonging to NGC 6791 is shown in Fig. 10 (triangles).

Star Type Ref. Period Ampl. Notes
[mag] [mag] [mag] [HJD–2452400] [d] [mag]



V119
EB 19.351961 37.916328 18.15 1.13 1.33 k 59.879 0.30197 0.15 member ?
V29 EB 19.354796 37.751386 20.00 1.23 1.61 k 69.012 0.43662 0.22 likely memb.
01558_5 EB 19.372697 37.953469 19.15 69.028 0.52910 0.28 likely non–memb.
01393_1 EA 19.329588 37.970392 21.23 59.326 0.58998 0.56 likely non–memb.
00331_3 EB 19.352367 37.864391 19.73 1.20 1.36 k 68.815 0.7347 0.13 member ?
V11 EA 19.342575 37.804802 19.38 0.96 1.22 k 67.875 0.8833 0.48 member ?
05736_9 EA 19.348484 37.721855 20.20 1.21 k 68.333 1.210 0.29 likely memb.
V12 EB 19.345259 37.849083 17.52 0.96 k 64.103 1.524 0.06 member (96%)
00645_10 EA 19.354692 37.710104 20.60 1.33 1.46 k 60.893 1.451 0.20 likely memb.
V9 EB 19.346634 37.777035 17.15 1.23 1.38 k 63.873: 3.2 0.2 member (82%)
V107 EA 19.355068 37.761553 17.97 0.93 1.00 k 64.433 3.27 0.24 member ?
V109 EA 19.342716 37.793961 20.73 1.46 1.60 k 69.021 3.70 0.86 member ?
Table 5: Eclipsing variables with well defined light curves. EA stands for a Per system, EB for a Lyr one. is the brightness at maximum and is the time of the primary minimum. Also B4, V60 and 02461_8, whose parameters are reported in the Appendix, are possible cluster members. The last column shows the Cudworth membership probability (when available).
Figure 10: The CMDs for the binary systems belonging to NGC 6791. Filled circles are contact binaries (W UMa stars), triangles are detached or semi–detached systems ( Per or Lyr systems).

4.6 Rotational variables

We found 89 variables whose light curves are characterized by small amplitude (usually less than 0.10 mag) and continuous variability. It is difficult to ascribe such variability to contact binaries undergoing grazing eclipses, since they should be less numerous than those having partial eclipses, since grazing eclipses occur only for a particular orientation of the orbital plane. Our hypothesis is that in most cases this variability results from spots carried by the stellar rotation; under this hypothesis, a large variety of light curves can be produced. Of course, we cannot rule out that a small fraction of these light curves might be actually generated by grazing eclipses.

The complete list of the rotational variables and their light curves is given in the Appendix. Here we discuss some examples. If the inclination of the rotational axis causes the progressive disappearance of the largest spots, the light curve displays continuous variation, which could be sine shaped in the simplest cases (a fraction of the spots is always visible; it can also produce Cepheid–like variability, as in the 001606_1 case, Fig. 12), or with a standstill (the hot or cold spots totally disappear; 00513_2 in Fig. 12) or, more commonly, it can be distorted by other spots besides the largest ones (00471_12 in Fig. 12). In cases of very active stars, a secondary wave also occurs (01175_5 in Fig. 12). Since the second wave often covers less than half of the period, these rotational variables can be distinguished from eclipsing binaries; we also note that the amplitude ratio between the first and second waves can be very different.

Also in the three cases in which the full amplitude is larger than 0.10 mag (V2, 02006_1 and 07483_9) rotational effects explain the observed features better than eclipses. For example, the light curves of V2 (=0.273 d) and 01298_5 (=0.586 d; see Fig. 12) show typical eclipsing binary behaviour, but the amplitudes, the periods, and, mainly, the asymmetries are more typical of a rotational effect. The case of 02270_11 is different (Fig. 12). Its light curve is very similar to that of a contact binary, but it does not repeat exactly, and unusual scatter is observed through the cycle. We also note that this non-repetitive behaviour of the light curves, due to the spot activity, is the reason why several variables stars show residual standard deviations higher than expected.

Our periods for V34, V37 and V38 are approximately half of those given by M02, since these authors classified these variables as ellipsoidal ones; the large amplitudes (0.18, 0.06 and 0.13 mag) are more in favour of a variability resulting from large spots, rather than the purely geometrical effect of tidally distorted stars. We also note that V37 did not show any flare activity similar to that reported by M02 during our survey. We have also revised the classification of V16, considered an eclipsing binary by M02 and M03.

We count 33 rotational variables in the 10′–circle (i.e., 0.105 star/arcmin) centered on the cluster, while we have 56 variables in the remaining 924–arcmin area (i.e., 0.061 star/arcmin). We have color indices ( and/or ) for 48 stars; 33 of them have a radial distance less than 10′  from the cluster center. We can confirm the membership for 6 stars having proper motion membership: V16, V38, V42, V48, V53 and 03079_9. We have no photometric indices for V41; however, it is at only 2′  from the cluster center and its Cudworth probability membership is 77%. Therefore, we consider V41 a member. For V14 we have the opposite situation because this star is at 1′  from the cluster center and its positions in the CMDs agree very well with a membership, but the proper motion measurements rule out that it can be a cluster member (0%) (see Figure 13, V14 is displayed as a starred dot). As mentioned by M03, the positions of V17 in the CMDs are unusual. Other variables located below the subgiant branch like V17 were found in the open cluster M67 (Mathieu et al., (2003)) and in the globular cluster 47 Tuc (Albrow et al., (2003)). Probably these objects (named “red stragglers” or “sub-subgiant branch stars”) are the result of some kind of mass exchange between the members of a binary system.

Putting the rotational variables without proper motion measurements on the CMDs we could infer that 8 stars are located on or close to the MS (represented with filled circles in Fig. 13); thus we suggest that these 8 stars belong to the cluster as well. Among the variables at greater distances, for three stars (01149_2, 01122_4 and 00513_2, all located between 11′  and 13′) the membership is doubtful, since their position in the CMDs is unclear. The other stars show apparent magnitudes and/or color indices too discrepant to be considered active MS stars belonging to NGC 6791.

When considering the variables without color indices, only two (V41 and 01874_2) are at less than 10′from the cluster center. We know that V41 is a probable cluster member (membership probability 77%), but, at the moment, we have no valid reason to consider the other star as a member.

Table LABEL:rotbel lists the rotational variables we suggest as cluster members. The error bars on the period are  d for 1.0 d,  d for 1.02.0 d,  d for 2.05.0 d; periods longer than 5.0 d are tentative. Figure 13 shows the CMDs with the rotational variables belonging to the cluster (Tab. LABEL:rotbel) clearly indicated. We rejected as cluster members 16 stars out of 32 located within 10′  from the cluster center; i.e., we considered them to be stars of the Galactic field. We note that the resulting density of the Galactic field (0.051 star/arcmin) superimposed on the cluster is in good agreement with that of the surrounding galactic disk field (0.061 star/arcmin, see above), especially considering that Poisson statistics supply uncertainties around 0.01 on the density values.

The stellar rotation and the activity level are both expected to be small for single stars as old as NGC 6791. Therefore we suggest that the rotational variables belonging to the cluster are likely short–period binaries, whose rotational velocity and activity level have been enhanced by the tidal synchronization.

Figure 11: The light curves of short–period detached or semi–detached eclipsing binaries.
Figure 12: The light curves of a small sample of rotational variables, illustrating the growing importance of the second wave.
Figure 13: and diagrams for NGC 6791. The rotational variables that we suggest may belong to the cluster are indicated with filled circles. Triangles: stars belonging to the cluster according to the Cudworth’s membership; starred point: V14, open square: V17 (see text for details about these stars).
Star Type Ref. Period Ampl. Notes
[mag] [mag] [mag] [HJD–2452400] [d] [mag]
04803_9 RO1 19.347698 37.796043 21.81 1.33 1.84 s 61.799 1.1034 0.17 member (B06)
V82 RO1 19.344366 37.793381 19.01 1.00 1.02 k 56.481 1.1568 0.04 likely memb.
06553_9 RO1 19.349134 37.672577 19.26 1.04 1.13 s 61.421 1.3485 0.08 likely memb.
01724_9 RO1 19.344957 37.785362 20.73 1.29 1.69 s 64.410 1.6130 0.17 likely memb.
V38 RO1 19.351021 37.768288 18.82 0.96 k 55.630 1.96 0.13 member (92%)
03079_9 RO1 19.346190 37.754753 19.23 1.14 1.26 k 66.630 2.640 0.07 member (93%)
V14 RO1 19.347687 37.756874 18.58 0.93 1.05 k 55.933 5.45 0.05 non–member (0%)
V48 RO1 19.352076 37.718506 17.51 0.88 k 65.223 5.65 0.09 member (96%)
V17 RO1 19.344135 37.817928 17.92 1.20 1.28 k 63.211 6.523 0.04 member (88%)
V51 RO1 19.353382 37.748795 19.94 1.22 1.21 k 63.624 6.72 0.09 likely memb.
V52 RO1 19.355795 37.771935 17.49 0.88 0.88 k 64.345 7.06 0.03 likely memb.
V53 RO1 19.350233 37.743187 18.72 0.89 0.93 k 69.294 7.47 0.04 member (86%)
00436_3 RO2 19.352205 37.878635 18.92 0.92 1.08 k 60.018 0.26601 0.04 likely memb.
07483_9 RO2 19.349997 37.746311 21.28 1.32 1.70 s 60.465 0.4375 0.17 likely memb.
V41 RO2 19.347492 37.806892 19.09 60.000 0.4798 0.07 member (77%)
V42 RO2 19.350058 37.714867 19.51 1.05 1.16 k 60.323 0.5068 0.10 member (92%)
V16 RO2 19.352108 37.802662 17.79 0.93 1.01 k 67.713 2.182 0.03 member (96%)

Table 6: Rotational variables belonging to the cluster. is the mean brightness value. indicates the time of the maximum brightness. The last column shows the membership probability (when available) or our photometric membership. The two uncertain cases (V41 and V14) are also listed (see text).

4.7 Long-period variables

We detected numerous stars having different mean magnitudes on the different nights. Their behaviours are more diversified than those of the stars we considered as spurious on the basis of their close similarities. The resulting power spectra are dominated by terms at very low frequencies, corresponding to periods often much longer than 10 d. These periods cannot be evaluated in a precise way, being comparable or, more frequently, longer than our time baseline. Therefore, we can only argue that these stars are variables, either in a periodic or in an irregular way. Since we detected many spotted stars, it is quite obvious to think that most of these long-period variables are spotted stars having a rotational periods longer than 10 d. The mean amplitude of these stars is about 0.02 mag, except for 5 stars whose amplitude exceeds 0.1 mag.

Among the long-period variables, we used the Cudworth probabilities to establish the membership of 18 stars. In order to roughly estimate the membership of the remaining long-period variables we checked their locations in the CMDs, in the cases where at least one color is available. We suggest that 5 stars are likely members of NGC 6791: 02138_8, 01610_9, 04392_3, V75 and 02268_10 (see Figure 14). They lie along the MS or the red-giant branch and, furthermore, they are all located at distances smaller than 85, from the cluster center. Looking at the position of the variable V76  V85 (memberships: 97%) in both CMDs, we suggest that this star could be similar to the “sub-subgiant branch” star V17. In Figure 15 we show its light curve and those of the 5 stars that we suspect to belong to the cluster. Table LABEL:lptab lists the long-period variables we suggest as cluster members; the entire sample is listed in the Appendix.

Figure 14: and diagrams for NGC 6791. Filled circles: long–period variables that we suggest belong to the cluster. Filled triangles: long–period variables that belong to the cluster (membership probability higher than 76%.)
Figure 15: Light curve of the suspect “red straggler” V76  V85 and the five stars that we suggest may belong to the cluster.
Star Ref. Ampl. Notes Distance
[mag] [mag] [mag] [mag] arcmin


02138_8
19.341864 37.749653 19.68 1.12 1.18 k 0.06 likely memb. 4.6
02444_8 19.342766 37.810604 18.34 0.93 1.00 k 0.02 member (78%) 4.4
00510_9 19.343704 37.796719 18.67 0.94 0.98 k 0.03 member (83%) 3.4
01610_9 19.344818 37.740486 19.09 1.01 1.05 k 0.02 likely memb. 3.0
V94 19.345139 37.743549 17.54 0.88 0.92 k 0.03 member (90%) 2.7
V95 19.345295 37.792412 19.16 1.03 1.10 k 0.07 member (93%) 2.3
V56(=V96) 19.345908 37.763525 17.01 0.95 0.97 k 0.04 member (98%) 1.6
04392_3 19.345982 37.870571 17.90 0.88 0.92 k 0.02 likely memb. 6.1
V75 19.346651 37.766308 17.38 0.94 0.98 s 0.01 likely memb. 1.0
04133_9 19.347109 37.777020 18.47 0.94 0.98 k 0.04 member (98%) 0.7
V76(=V85) 19.347192 37.764169 18.19 1.03 1.15 k 0.11 member (97%) 0.8
V86 19.347258 37.808815 19.44 1.06 1.14 k 0.03 member (83%) 2.3
V87 19.347996 37.749668 18.12 0.91 0.93 k 0.03 member (98%) 1.3
05740_9 19.348534 37.808022 17.96 0.93 k 0.03 member (95%) 2.2
06725_9 19.349329 37.724495 17.77 0.91 k 0.02 member (91%) 3.0
06796_9 19.349415 37.769268 18.46 0.92 1.04 k 0.03 member (92%) 1.0
V90 19.349686 37.746449 18.11 0.86 0.94 k 0.01 member (94%) 1.9
07680_9 19.350193 37.718224 18.32 0.89 0.97 k 0.03 member (98%) 3.5
V31 19.350683 37.785912 17.12 1.00 1.02 k 0.01 member (97%) 2.1
09376_9 19.351952 37.831886 18.21 1.00 1.02 k 0.01 member (92%) 4.6
09611_9 19.352139 37.773365 17.97 0.85 0.91 k 0.01 member (76%) 2.9
V58 19.354042 37.801240 17.52 0.89 0.94 k 0.05 member (87%) 4.6
02268_10 19.359475 37.731544 18.59 0.95 0.99 k 0.02 likely memb. 8.5

Table 7: Long period variable stars that are likely members of NGC 6791 (ordered by increasing right ascension). The column 9 shows the membership probability (when available) or our photometric membership.

5 Conclusions

Our wide-field survey of NGC 6791 for the planetary-transit search allowed us to discover 260 new variable stars. When considering the membership probabilities given by Cudworth and B06, 13 of them belong to the cluster and one star (09831_9) is not member. On the basis of the distances from the cluster center and the positions in the CMDs, we suggest that another 11 stars are likely members, for 22 stars the membership is doubtful, and 137 stars are likely non-members. No photometric or kinematic data are available for 76 stars.

The variable star content of the cluster is very similar to that of the surrounding Galactic environment: in both samples we find rotational variables, contact and eclipsing systems. Contact binaries and rotational variables belonging to the cluster have the same characteristics as those located in the surrounding Galactic field. No evidence of pulsating variables has been found in NGC 6791, but this is not surprising, since it is a very evolved cluster and stars located in the instability strip or hotter pulsators have already left the MS.

The discovery of the new cataclysmic variable 06289_9 in addition to B8 and V15 adds another peculiarity to NGC 6791, making it unusual among the open clusters.

Acknowledgements.
We are grateful to Kyle Cudworth kindly providing us with preliminary cluster membership probabilities. We also acknowledge Prof. Antonio Bianchini for his suggestions about the characteristics of the candidate cataclysmic variable and Giovanni Carraro for his useful comments. We thank the referee, Dr. J. Kaluzny, for his detailed report and useful comments. This work was funded by COFIN 2004 “From stars to planets: accretion, disk evolution and planet formation” by MIUR and by PRIN 2006 “From disk to planetary systems: understanding the origin and demographics of solar and extrasolar planetary systems” by INAF.

Appendix A List of identified variables

This Appendix includes the full list of the identified variables, separated according to our classification:

  1. Pulsating, irregular and cataclysmic variables: Table: 8.

  2. EW–Type stars: Table 9, Figure 16.

  3. EA/EB–type stars: Table 10.

  4. Single–wave rotational variables: Tables 11, 12, Figures 17, 18.

  5. Double–wave rotational variables: Table 13, Figure 19.

  6. Long–period variables: Table 14.

Into the tables, for each star we give the name (a five–digit number followed by the chip number which the star belongs), coordinates, photometric data (always the mag, color when available), informations about the variability (, period, amplitude), distance from the center (in arcmin) and finally the numerical value of the Cudworth’s membership probability (reported in the column ’Memb.’).

In most cases, when membership probabilities were not available, in the same column the label “m” means that we retain the star belonging to the cluster, while ’m?’ and “nm” mean “uncertain membership” and “likely non–member” respectively. The label “nd1” means that no photometric data are available to advance hypothesis about the membership, but the star is located nearer than 10′  from the center of the cluster. Finally “nd2” means that no photometric data are available and the star is located further than 10′  from the center; in this case we strongly suggest that the star does not belongs to the cluster.

Star Type Ref. Period Ampl. Memb. Distance
[mag] [mag] [mag] [HJD–2452400] [d] [mag] [arcmin]




V123
HADS 19.362064 37.666034 17.08 0.45 k 59.559 0.06026 0.14 nm 11.8
01497_12 HADS 19.379083 37.812419 16.06 59.528 0.07227 0.40 nd2 22.2
00311_7 SXPhe 19.324628 37.716768 23.17 59.605 0.10443 0.10 nd2 17.0
00224_10 SXPhe 19.353639 37.710163 21.72 0.71 1.06 s 59.801 0.12261 0.20 nm 5.4
03653_3 RRc 19.347147 37.992413 17.21 0.57 0.58 k 59.937 0.32654 0.39 nm 13.3
00345_1 RRab 19.325082 37.964170 18.28 60.151 0.57866 0.72 nd2 20.0
V92 IRR 19.350754 37.766876 18.10 0.91 k 0.10 m 1.9
V83 IRR 19.346220 37.737232 19.10 1.02 1.05 k 0.07 m 2.4
V93 IRR 19.351452 37.785687 18.12 0.98 1.03 s 0.04 m 2.6
V15(=B7) CV 19.352057 37.799019 18.26 0.20 k 0.06 98 3.3
B8 CV 19.343262 37.747833 20.64 –0.23 0.78 k 2.27 m 3.7
06289_9 CV 19.348976 37.770355 22.80 0.25 0.88 s 3.10 m (B06) 0.7

Table 8: Pulsating, irregular and cataclysmic variables. is the minimum brightness for CVs and irregular, the mean brightness for pulsating variables. is the time of maximum brightness for pulsating stars.

Star
Ref. Period Ampl. Memb. Distance
[mag] [mag] [mag] [HJD–2452400] [d] [mag] [arcmin]


V122
19.360729 37.641436 20.92 59.614 0.22883 0.58 nd2 11.9
V115 19.330646 37.975902 20.70 59.473 0.23636 0.24 nd2 17.4
01407_8 19.339256 37.701576 21.52 0.64 1.25 k 59.447 0.24155 0.82 nm 7.5
01150_4 19.357227 37.962177 18.58 1.07 0.93 k 59.455 0.24510 0.27 nm 13.2
01441_8 19.339422 37.778118 19.98 1.38 k 63.073 0.24544 0.07 m 6.2
00144_2 19.334044 38.030701 19.19 59.457 0.24780 0.77 nd2 18.5
01670_10 19.357625 37.681442 16.64 1.14 1.24 k 59.729 0.25807 0.49 nm 8.7
V121 19.358063 37.932346 17.24 0.81 0.84 k 59.619 0.26742 0.71 nm 12.0
02291_11 19.371624 37.795464 19.15 59.582 0.26774 0.29 nd2 16.8
V23 19.338614 37.787781 16.92 1.04 1.23 k 59.915 0.27180 0.07 nm 6.8
V25 19.328426 37.713237 18.50 59.772 0.27730 0.56 nd2 14.4
00665_12 19.375697 37.713244 18.89 59.472 0.28369 0.41 nd2 20.0
09831_9 19.352356 37.780907 20.55 1.09 1.19 s 59.662 0.29488 0.3 nm (B06) 3.1
01434_3 19.350643 37.985512 22.10 59.831 0.30581 0.97 nd2 13.0
V118 19.347500 37.651222 17.68 0.75 1.01 s 59.912 0.30623 0.70 m 7.2
00721_11 19.365737 37.713858 15.53 59.491 0.31008 0.26 nd2 13.1
01701_2 19.341944 38.017998 18.72 59.534 0.31201 0.51 nd2 15.4
V5 19.346258 37.813354 17.19 0.90 0.95 k 60.221 0.31274 0.05 98 2.8
V3 19.354380 37.769349 18.51 1.05 1.06 k 59.798 0.31764 0.09 78 4.5
02030_4 19.353487 38.009422 19.04 1.19 1.42 k 59.614 0.31797 0.33 nm 14.8
V124 19.365150 37.681544 17.62 0.70 1.07 k 59.855 0.32014 0.58 nm 13.3
00766_5 19.367585 37.943904 22.31 59.466 0.32363 0.78 nd2 17.3
V4 19.348396 37.806652 17.72 1.01 k 59.591 0.32568 0.10 98 2.1
V27 19.336275 37.648720 18.47 0.82 1.29 k 59.763 0.33170 0.84 nm 11.2
V8 19.341938 37.865810 17.81 0.79 0.88 k 59.896 0.33406 0.10 m 7.1
V101 19.351563 37.640388 19.94 0.56 k 59.798 0.33480 0.29 nm 8.3
V117 19.343433 37.665848 17.66 0.87 0.90 k 59.987 0.36644 0.38 m 7.2
V7 19.340271 37.821892 17.63 0.93 0.86 k 59.820 0.39174 0.31 m 6.3
V40 19.327495 37.616839 19.67 60.101 0.39750 0.16 nd2 17.3

Table 9: Contact binaries; is the brightness at maximum and is the time of the primary minimum.
Figure 16: Contact variables.
Star Type Ref. Period Ampl. Memb. Distance Notes
[mag] [mag] [mag] [HJD–2452400] [d] [mag] [arcmin]


V119
EB 19.351961 37.916328 18.15 1.13 1.33 k 59.879 0.30197 0.15 m? 9.1
B4 E: 19.353589 37.764290 17.87 –0.13 –0.15 k 54.788 0.39841 0.02 40 4.0
V29 EB 19.354796 37.751386 20.00 1.23 1.61 k 69.012 0.43662 0.22 m 4.9 Light curve distortion
at maximum light
01558_5 EB 19.372697 37.953469 19.15 69.028 0.52910 0.28 nd2 20.6
01393_1 EA 19.329588 37.970392 21.23 59.326 0.58998 0.56 nd2 17.7
00331_3 EB 19.352367 37.864391 19.73 1.20 1.36 k 68.815 0.7347 0.13 m? 6.4
V11 EA 19.342575 37.804802 19.38 0.96 1.22 k 67.875 0.8833 0.48 m? 4.4
05736_9 EA 19.348484 37.721855 20.20 1.21 k 68.333 1.210 0.29 m 3.0
V12 EB 19.345259 37.849083 17.52 0.96 k 64.103 1.524 0.06 96 5.1
00645_10 EA 19.354692 37.710104 20.60 1.33 1.46 k 60.893 1.451 0.20 m 6.0
V9 EB 19.346634 37.777035 17.15 1.23 1.38 k 63.873 3.2 0.20 82 1.1
V107 EA 19.355068 37.761553 17.97 0.93 1.00 k 64.433 3.27 0.24 m? 5.0 Minima at the very
beginning of the night.
V109 EA 19.342716 37.793961 20.73 1.46 1.60 k 69.021 3.70 0.86 m? 4.0
00219_11 EA 19.364048 37.827507 17.94 0.92 0.87 k 67.913 0.52 nm 11.9
00663_4 EA 19.359652 37.894062 17.49 0.79 0.83 k 65.003 0.49 nm 11.0
00671_2 EA 19.336983 37.903919 18.46 0.70 0.91 k 64.968 0.07 nm 11.2
00828_5 EA 19.367917 37.885330 21.28 64.979 0.38 nd2 15.7
00938_2 EA 19.338285 37.861633 20.57 1.20 1.80 k 67.867 0.60 nm 8.8
00997_10 EA 19.355692 37.799655 19.58 0.76 0.83 k 68.020 0.20 nm 5.7
01709_1 EA 19.330890 37.932268 18.04 64.818 0.32 nd2 15.5
01731_10 EA 19.357813 37.672819 19.27 0.67 0.80 k 64.783 0.34 nm 9.1 Minimum at the very
beginning of the night.
01780_8 EA 19.340677 37.655354 22.19 2.25 k 68.969 0.66 nm 8.7
02461_8 EA 19.342779 37.741798 19.34 1.06 1.15 k 60.968 0.11 88 4.2
01740_7 EA 19.330623 37.638774 21.30 69.007 0.33 nd2 14.8 Maybe another minimum
at 64.40
02045_12 EA 19.381420 37.712211 17.16 68.030 0.26 nd2 24.0 Other minimum at 63.39
02241_11 EA 19.371472 37.827819 19.21 68.823 0.53 nd2 17.0 Maybe another minimum
at 63.50
00346_5 EA 19.365356 37.929481 20.16 65.014 0.17 nd2 15.5 Other minimum at
at 68.410. Short in time.
00631_12 EA 19.375473 37.649140 17.92 68.753 0.30 nd2 20.9 Minimum at the very
beginning of the night.
01511_10 EA 19.357145 37.689907 19.74 1.45 1.86 k 0.50 nm 8.1 Two Minima at night extrema.
V60 EA 19.350189 37.762493 18.68 0.96 k 67.951 0.39 91 1.6
V80 EA 19.351799 37.791061 17.90 0.94 k 67.607 4.631 0.10 86 2.9 Shallow eclipse ?
 V108 EA 19.352606 37.823467 21.15 1.27 1.90 k 69.080 0.86 nm 4.5

Table 10: Eclipsing variables. is the brightness at maximum and is the time of the primary minimum.

Star
Ref. Period Ampl. Memb. Distance
[mag] [mag] [mag] [HJD–2452400] [d] [mag] [arcmin]




02268_12
19.382495 37.798839 17.42 60.323 0.30910 0.02 nd2 24.6
02418_3 19.349085 38.016541 21.68 59.901 0.36498 0.12 nd2 14.7
00513_2 19.336012 37.940765 20.12 1.18 1.51 k 60.786 0.45272 0.08 m? 13.3
02292_10 19.359535 37.710207 16.24 1.11 1.25 k 61.298 0.46371 0.06 nm 9.0
01497_11 19.368601 37.770512 18.58 61.737 0.56508 0.01 nd2 14.6
01776_4 19.354509 37.935883 19.70 0.99 1.16 k 61.154 0.68029 0.06 nm 10.9
00301_5 19.365041 37.906284 22.10 62.833 0.70170 0.21 nd2 14.5
00088_8 19.333437 37.744888 21.92 65.464 0.70594 0.11 nd2 10.5
V43 19.344337 37.641777 19.58 1.62 2.97 k 55.976 0.75759 0.08 nm 8.2
00554_8 19.335732 37.664570 21.32 1.22 1.48 k 65.543 0.821 0.13 nm 10.9
00612_10 19.354604 37.729215 22.97 0.79 2.42 s 68.050 0.91581 0.24 m? 5.3
01105_12 19.377359 37.737573 19.31 62.539 0.91746 0.04 nd2 21.0
00913_5 19.368442 37.859339 20.89 62.405 1.06386 0.24 nd2 15.4
04803_9 19.347698 37.796043 21.81 1.33 1.84 s 61.799 1.1034 0.17 m (B06) 1.5
01606_11 19.368978 37.736585 20.36 62.390 1.12360 0.10 nd2 15.0
V82 19.344366 37.793381 19.01 1.00 1.02 k 56.481 1.1568 0.04 m 2.9
V34 19.335878 37.736183 19.30 1.16 1.41 k 54.955 1.20486 0.18 nm 8.9
05302_3 19.344669 37.968491 18.90 63.224 1.3334 0.15 nd2 12.1
06553_9 19.349134 37.672577 19.26 1.04 1.13 s 61.421 1.3485 0.08 m 6.0
00471_12 19.374883 37.674950 19.35 61.900 1.3513 0.06 nd2 20.0
00110_5 19.363887 38.001389 21.69 62.103 1.4085 0.08 nd2 17.8
01874_2 19.342730 37.912987 21.96 64.944 1.5503 0.14 nd1 9.3
V111 19.346970 37.812141 20.67 1.46 1.66 s 61.673 1.5626 0.15 nm 2.5
V37 19.355072 37.852001 19.58 1.65 2.48 k 55.721 1.6130 0.06 nm 6.9
01724_9 19.344957 37.785362 20.73 1.29 1.69 s 64.410 1.6130 0.17 m 2.4
02285_10 19.359424 37.607155 19.26 1.34 1.57 k 63.495 1.6668 0.08 nm 12.8
01189_11 19.367513 37.809413 20.46 64.500 1.7242 0.10 nd2 14.0
00016_5 19.363396 37.997513 18.68 1.54 2.52 k 63.157 1.7858 0.07 nm 17.4
00732_12 19.375889 37.717569 19.39 61.992 1.852 0.04 nd2 20.1
00771_11 19.365949 37.766208 19.52 62.492 1.852 0.09 nd2 12.7
00676_1 19.326459 37.929277 20.54 65.481 1.887 0.11 nd2 18.0
V38 19.351021 37.768288 18.82 0.96 k 55.630 1.96 0.13 92 2.1
02103_7 19.332028 37.696796 19.57 1.65 k 60.891 2.041 0.05 nm 12.3
00575_12 19.375449 37.792459 19.63 65.359 2.214 0.02 nd2 19.5
01914_1 19.331830 37.878855 17.71 0.73 k 62.358 2.222 0.03 nm 13.2
03838_3 19.346848 37.964615 19.45 0.91 1.05 k 64.159 2.261 0.04 nm 11.6
V44 19.326970 37.694771 18.38 58.310 2.285 0.02 nd2 15.7
00321_1 19.324957 37.905996 19.49 65.394 2.326 0.04 nd2 18.3
00810_5 19.367793 37.865903 18.17 67.424 2.564 0.05 nd2 15.1
03079_9 19.346190 37.754753 19.23 1.14 1.26 k 66.630 2.640 0.07 93 1.7
01821_12 19.380347 37.604033 20.13 70.829 2.647 0.06 nd2 25.1
01309_11 19.367871 37.748052 20.81 61.125 2.692 0.05 nd2 14.2
01956_12 19.380972 37.626492 21.39 63.833 2.699 0.06 nd2 25.0
00815_1 19.327108 37.861623 19.75 63.358 2.836 0.05 nd2 15.8
01659_8 19.340244 37.694355 21.27 1.51 1.85 k 64.446 2.840 0.17 nm 7.2
00293_11 19.364252 37.703417 15.82 0.80 0.88 k 63.606 2.941 0.05 nm 12.2
00215_5 19.364447 37.898928 22.26 65.340 3.15 0.14 nd2 13.9
03209_10 19.362653 37.732028 18.61 1.54 2.57 k 66.016 3.17 0.06 nm 10.7
01313_1 19.329261 38.025661 21.27 62.466 3.704 0.10 nd2 20.3
00277_8 19.334366 37.776566 19.52 1.54 2.68 k 60.691 4.167 0.05 nm 9.7
00179_5 19.364283 38.002234 17.18 0.91 0.90 k 64.764 4.323 0.04 nm 18.0
03039_10 19.362130 37.815850 16.58 0.79 0.87 k 65.634 4.423 0.02 nm 10.4
01555_4 19.355373 37.961205 21.22 69.673 4.546 0.09 nd2 12.5
02614_11 19.372592 37.625244 17.22 70.152 4.763 0.04 nd2 19.6
01149_2 19.339287 37.966995 17.80 0.90 0.93 k 67.803 5.0 0.04 m? 13.3
02815_3 19.348427 37.967987 19.87 1.68 2.40 k 60.828 5.0 0.05 nm 11.8
V46 19.355272 37.798869 18.65 1.18 1.36 k 56.886 5.2 0.14 nm 5.4
00357_5 19.365449 37.996214 20.91 63.108 5.3 0.07 nd2 18.3
01484_7 19.329583 37.791249 20.30 1.63 k 67.924 5.3 0.03 nm 13.2
V14 19.347687 37.756874 18.58 0.93 1.05 k 55.933 5.45 0.05 0 0.9
V48 19.352076 37.718506 17.51 0.88 k 65.223 5.65 0.09 96 4.3


Continue …

Table 11: Rotational variables with a single–wave light curve. is the mean brightness value. indicates the time of the maximum brightness.

Star
Ref. Period Ampl. Memb. Distance
[mag] [mag] [mag] [HJD–2452400] [d] [mag] [arcmin]


00615_7
19.325908 37.753712 20.59 59.885 5.882 0.14 nd2 15.8
V89 19.349068 37.776783 18.75 0.88 1.20 s 63.447 5.884 0.05 nm 0.8
00188_12 19.373720 37.632076 21.78 67.253 6.25 0.06 nd2 20.1
V17 19.344135 37.817928 17.92 1.20 1.28 k 63.211 6.523 0.04 88 3.9
01122_4 19.357346 37.914520 18.84 1.03 1.12 k 65.843 6.69 0.11 m? 10.8
03056_3 19.347979 37.869431 17.10 0.89 0.97 k 66.673 6.70 0.07 nm 5.9
V51 19.353382 37.748795 19.94 1.22 1.21 k 63.624 6.72 0.09 m 4.0
00640_10 19.354585 37.604724 17.97 0.68 0.77 k 66.173 6.8 0.03 nm 11.0
V52 19.355795 37.771935 17.49 0.88 0.88 k 64.345 7.06 0.03 m 5.5
V53 19.350233 37.743187 18.72 0.89 0.93 k 69.294 7.47 0.04 86 2.3
01431_10 19.357001 37.763810 17.72 1.33 1.45 k 67.953 7.64 0.26 nm 6.4
01616_11 19.369060 37.767818 17.26 69.157 7.70 0.05 nd2 14.9
01478_3 19.350523 37.862484 17.15 1.03 1.11 k 72.123 7.96 0.07 nm 5.7
05877_9 19.348616 37.767616 20.22 1.32 1.49 k 64.272 8.0 0.12 nm 0.5

Table 12: Continue from Table 11: other rotational variables with a single–wave light curve. is the mean brightness value. indicates (one of) the times of maximum brightness.

Star
Ref. Period Ampl. Memb. Distance
[mag] [mag] [mag] [HJD–2452400] [d] [mag] [arcmin]



00436_3
19.352205 37.878635 18.92 0.92 1.08 k 60.018 0.26601 0.04 m 7.1
V2 19.354875 37.766689 19.74 0.93 1.21 k 59.712 0.27344 0.17 nm 4.9
02006_1 19.332258 38.043080 21.54 60.448 0.37500 0.19 nd2 19.8
01175_5 19.370209 37.998342 19.73 59.918 0.41481 0.09 nd2 20.8
00536_11 19.365067 37.716529 19.13 60.460 0.43740 0.03 nd2 12.6
07483_9 19.349997 37.746311 21.28 1.32 1.70 s 60.465 0.4375 0.17 m 2.1
V41 19.347492 37.806892 19.09 60.000 0.4798 0.07 77 2.2
V42 19.350058 37.714867 19.51 1.05 1.16 k 60.323 0.5068 0.10 92 3.7
01362_7 19.329000 37.662097 20.53 60.502 0.5560 0.08 nd2 15.1
02270_11 19.371548 37.794338 17.95 60.525 0.5679 0.05 nd2 16.8
01298_5 19.371044 38.002255 19.76 60.402 0.5859 0.06 nd2 21.4
V16 19.352108 37.802662 17.79 0.93 1.01 k 67.713 2.182 0.03 96 3.4
00568_2 19.336329 37.881542 18.52 60.007 2.704 0.08 nd2 10.6
00019_7 19.323382 37.710172 18.95 65.473 5.882 0.12 nd2 17.9

Table 13: Rotational variables with a double–wave light curve. is the mean brightness value. indicates (one of) the times of maximum brightness.
Figure 17: Rotational variables with a single–wave light curve, in some cases very distorted.
Figure 18: Rotational variables with a single–wave light curve, in some cases very distorted.
Figure 19: Rotational variables with a single–wave (from V51 to 05877_9) and a double–wave light curve.

Star
Ref. Memb. Distance Star Ref. Memb. Distance
[mag] [mag] [mag] [arcmin] [mag] [mag] [mag] [arcmin]



00091_1
19.323698 37.943716 19.16 nd2 20.2 V90 19.349686 37.746449 18.11 0.86 0.94 k 94 1.9
00143_1 19.323947 37.927971 20.11 nd2 19.5 02011_3 19.349693 37.958382 19.50 1.19 1.16 k nm 11.3
00250_7 19.324384 37.779393 18.32 nd2 16.8 01908_3 19.349867 37.947132 19.29 1.05 1.09 k m? 10.6
00326_7 19.324675 37.719342 17.99 nd2 16.9 V91 19.350151 37.811325 18.07 0.83 0.91 k m? 2.8
00364_7 19.324832 37.798606 20.17 nd2 16.6 07680_9 19.350193 37.718224 18.32 0.89 0.97 k 98 3.5
00377_1 19.325260 38.018518 18.72 nd2 21.9 07914_9 19.350483 37.822048 18.64 1.12 1.27 s m? 3.5
00466_7 19.325296 37.809032 14.65 nd2 16.3 V100 19.350498 37.761631 17.13 1.02 k m? 1.8
00435_1 19.325525 37.990790 16.89 nd2 20.7 V31 19.350683 37.785912 17.12 1.00 1.02 k 97 2.1
00537_1 19.325956 38.059293 18.33 nd2 23.3 01344_3 19.350784 37.970558 18.17 1.33 1.48 k nm 12.1
00552_1 19.325972 37.941670 18.10 nd2 18.7 V62 19.350847 37.731068 19.45 1.02 1.07 k m? 3.1
00651_7 19.326084 37.647564 16.89 nd2 17.3 01252_3 19.350937 37.911869 19.85 1.55 2.66 k nm 8.7
00819_7 19.326732 37.764538 18.02 nd2 15.2 08747_9 19.351194 37.651299 21.32 1.50 1.71 s nm 7.6
00836_7 19.326803 37.684309 19.78 nd2 16.0 00990_3 19.351418 38.014648 17.29 nd2 14.8
00804_1 19.327102 38.039468 21.14 nd2 21.9 V110 19.351603 37.741802 17.75 0.71 0.76 k 25 3.1
00814_1 19.327140 38.035436 20.78 nd2 21.7 09376_9 19.351952 37.831886 18.21 1.00 1.02 k 92 4.6
00973_1 19.327784 37.996820 19.17 nd2 19.7 09611_9 19.352139 37.773365 17.97 0.85 0.91 k 76 2.9
01095_7 19.327905 37.726883 15.41 nd2 14.6 V66 19.352339 37.748669 15.95 1.29 1.39 k m? 3.3
01145_1 19.328562 38.051636 20.12 nd2 21.8 00038_3 19.352835 37.851254 19.06 0.88 0.97 k m? 5.9
01382_7 19.329091 37.812623 18.99 nd2 13.7 00176_10 19.353423 37.611797 17.90 1.39 1.59 k nm 10.3
01536_7 19.329780 37.640689 17.85 0.91 k nm 15.2 V58 19.354042 37.801240 17.52 0.89 0.94 k 87 4.6
01513_1 19.330106 37.876259 17.18 0.70 k nm 14.2 00630_10 19.354660 37.738732 18.98 1.27 1.29 k m? 5.1
01746_7 19.330667 37.812027 18.84 1.08 k nm 12.6 00670_10 19.354823 37.806999 23.18 -0.40 0.54 s m? 5.3
01829_7 19.330990 37.707912 15.20 1.31 k nm 12.7 01536_4 19.355383 37.882149 17.21 1.18 1.29 k nm 8.4
01873_1 19.331671 37.912256 19.41 0.98 k nm 14.4 01415_4 19.355972 38.000843 17.60 1.50 1.92 k nm 14.9
02096_7 19.332013 37.776243 16.79 1.05 k nm 11.4 01169_10 19.356078 37.634936 15.34 0.88 1.02 k nm 10.0
02126_7 19.332109 37.673400 19.20 1.38 k nm 12.8 V55 19.356228 37.841698 16.12 1.48 1.88 k nm 7.2
02004_1 19.332252 38.055218 19.85 nd2 20.4 01232_10 19.356296 37.664158 19.31 1.41 1.64 k nm 8.7
02262_7 19.332626 37.658640 17.99 0.77 k nm 12.9 01225_10 19.356349 37.770012 21.02 2.91 k nm 5.9
V114 19.333338 37.812103 17.60 1.10 1.15 k m? 10.7 01279_10 19.356519 37.757845 20.83 1.00 1.22 k nm 6.1
00285_2 19.334742 38.038967 19.13 nd2 18.6 01210_4 19.356915 37.957123 17.69 0.75 0.86 k nm 12.8
00404_8 19.335062 37.790737 18.68 0.69 k nm 9.3 01417_10 19.356934 37.756828 17.03 1.11 1.17 k nm 6.4
00386_2 19.335152 37.960213 21.51 nd2 14.6 01101_4 19.357428 37.882973 18.25 1.02 1.11 k nm 9.4
00620_8 19.335981 37.656742 18.99 1.61 2.08 k nm 11.0 01082_4 19.357555 37.938122 20.49 1.24 1.10 k nm 12.1
00791_2 19.337513 38.014545 18.01 nd2 16.4 01070_4 19.357592 37.913498 17.53 1.49 2.15 k nm 10.9
00907_2 19.338146 38.041290 15.62 nd2 17.6 01682_10 19.357705 37.729503 18.40 0.93 0.98 k m? 7.3
01212_8 19.338499 37.721958 18.45 0.99 1.10 s nm 7.4 01807_10 19.358104 37.721153 18.17 1.49 2.02 k nm 7.8
01222_8 19.338552 37.737770 18.26 1.12 1.18 k nm 7.1 00920_4 19.358349 37.962833 17.65 0.98 1.00 k nm 13.6
01126_2 19.339148 37.937424 16.93 nd2 11.8 01885_10 19.358407 37.824782 19.23 0.83 0.88 k nm 8.0
01122_2 19.339149 38.031670 18.55 nd2 16.8 02145_10 19.359033 37.664901 16.66 1.24 1.36 k nm 10.1
01406_8 19.339247 37.695103 19.03 1.22 1.37 k nm 7.8 02165_10 19.359100 37.668317 19.60 1.54 2.31 k nm 10.0
V59 19.339304 37.806061 17.96 1.30 1.42 k nm 6.6 02250_10 19.359370 37.663215 18.71 0.99 1.12 k nm 10.4
01179_2 19.339432 37.995293 19.66 nd2 14.7 00717_4 19.359394 37.895435 18.02 1.28 1.42 k nm 11.0
01622_8 19.340046 37.629841 18.09 1.42 1.64 k nm 10.2 00718_4 19.359436 37.961086 20.26 1.44 1.67 k nm 13.9
02022_8 19.341475 37.682644 18.58 1.27 1.44 k nm 7.1 02268_10 19.359475 37.731544 18.59 0.95 0.99 k m 8.5
02108_8 19.341743 37.645943 19.50 0.97 1.12 k nm 8.8 00598_4 19.360041 37.997711 16.73 0.90 1.05 k nm 16.0
02138_8 19.341864 37.749653 19.68 1.12 1.18 k m 4.6 00569_4 19.360079 37.848969 19.88 1.23 1.28 k nm 9.7
02444_8 19.342766 37.810604 18.34 0.93 1.00 k 78 4.4 00538_4 19.360250 37.932350 17.58 0.96 0.99 k nm 13.0
06098_3 19.343510 38.050224 18.50 nd2 17.0 00422_4 19.360813 37.962696 18.18 1.00 1.12 k nm 14.6
05998_3 19.343616 37.956688 19.21 1.39 1.52 k nm 11.5 00381_4 19.360947 37.864788 19.81 1.62 2.35 k nm 10.7
05951_3 19.343662 37.927708 18.06 nd1 9.9 00313_4 19.361338 37.894558 18.56 0.72 0.79 k nm 12.0
05938_3 19.343676 37.927959 18.19 nd1 9.9 02898_10 19.361434 37.604020 22.56 nd2 13.9
00510_9 19.343704 37.796719 18.67 0.94 0.98 k 83 3.4 02924_10 19.361641 37.711676 18.04 1.47 1.82 k nm 10.3
05870_3 19.343727 37.882679 21.96 nd1 7.3 00092_11 19.363431 37.702573 18.52 1.63 1.95 k nm 11.7
00835_9 19.344023 37.766895 20.02 1.21 1.25 k m? 2.9 00097_5 19.363811 37.998650 19.70 0.97 0.99 k nm 17.6
05677_3 19.344053 37.908951 18.83 1.50 1.81 k nm 8.7 00473_11 19.364836 37.670896 19.83 0.75 0.91 k nm 13.4
05524_3 19.344362 38.041668 20.16 nd2 16.4 00297_5 19.365023 37.926561 22.15 nd2 15.2
01610_9 19.344818 37.740486 19.09 1.01 1.05 k m 3.0 00553_11 19.365157 37.749285 16.26 0.92 1.02 k nm 12.2
05014_3 19.345045 37.876141 16.24 1.06 1.17 k m? 6.6 00448_5 19.365911 37.852960 17.32 nd2 13.6
V94 19.345139 37.743549 17.54 0.88 0.92 k 90 2.7 00819_11 19.366089 37.737134 18.77 nd2 13.0
V95 19.345295 37.792412 19.16 1.03 1.10 k 93 2.3 00521_5 19.366291 37.911656 17.26 nd2 15.4
04768_3 19.345497 37.987465 19.83 1.16 1.22 k m? 13.1 00601_5 19.366800 37.992387 17.91 nd2 18.8
04666_3 19.345663 38.023544 15.83 nd2 15.2 01021_11 19.366890 37.806929 17.40 nd2 13.6
02716_9 19.345829 37.651981 17.69 1.45 1.73 k nm 7.4 00793_5 19.367687 37.917070 18.32 nd2 16.5
V56(=V96) 19.345908 37.763525 17.01 0.95 0.97 k 98 1.6 01304_11 19.367749 37.637939 18.65 nd2 16.2
04392_3 19.345982 37.870571 17.90 0.88 0.92 k m 6.1 00922_5 19.368542 37.950158 18.62 nd2 18.1
04368_3 19.346024 37.882671 19.62 1.13 1.12 k m? 6.8 01525_11 19.368695 37.773095 18.81 nd2 14.7
04293_3 19.346100 37.838703 19.46 nd1 4.3 01695_11 19.369359 37.789309 17.96 nd2 15.2
04298_3 19.346115 37.886810 18.35 0.78 0.92 k nm 7.0 01785_11 19.369770 37.820589 17.13 nd2 15.7
04160_3 19.346313 37.864944 17.34 1.06 1.11 k m? 5.7 02010_11 19.370466 37.700018 19.73 nd2 16.5
03987_3 19.346600 37.910511 19.17 1.04 1.10 k m? 8.4 01245_5 19.370613 37.897333 18.30 nd2 17.7
V75 19.346651 37.766308 17.38 0.94 0.98 s m 1.0 02401_11 19.371975 37.721131 16.62 nd2 17.3
03687_9 19.346727 37.787651 20.13 1.07 1.45 k m? 1.3 02419_11 19.371994 37.662943 17.30 nd2 18.2
03859_3 19.346788 37.889477 20.95 1.11 1.85 k nm 7.1 02550_11 19.372438 37.653960 21.54 nd2 18.7
04133_9 19.347109 37.777020 18.47 0.94 0.98 k 98 0.7 00941_12 19.376714 37.722466 17.77 nd2 20.6
V76(=V85) 19.347192 37.764169 18.19 1.03 1.15 k 97 0.8 01041_12 19.376987 37.656970 17.89 nd2 21.7
V86 19.347258 37.808815 19.44 1.06 1.14 k 83 2.3 01038_12 19.377120 37.779197 20.33 nd2 20.7
V87 19.347996 37.749668 18.12 0.91 0.93 k 98 1.3 01150_12 19.377457 37.669195 17.18 nd2 21.8
05487_9 19.348234 37.677147 18.53 0.93 1.01 k m? 5.7 01275_12 19.378092 37.727700 20.16 nd2 21.5
05673_9 19.348469 37.793930 20.61 1.29 1.62 k m? 1.4 01807_12 19.380555 37.832929 18.99 nd2 23.4
05740_9 19.348534 37.808022 17.96 0.93 k 95 2.2 01915_12 19.381010 37.826766 20.20 nd2 23.7
06509_9 19.349110 37.684639 20.79 1.37 1.79 k m? 5.3 02001_12 19.381172 37.629091 20.49 nd2 25.1
06532_9 19.349180 37.785137 18.01 0.91 0.95 s m? 1.1 01961_12 19.381188 37.780646 17.87 nd2 23.6
06725_9 19.349329 37.724495 17.77 0.91 k 91 3.0 01968_12 19.381265 37.804920 18.71 nd2 23.7
06796_9 19.349415 37.769268 18.46 0.92 1.04 k 92 1.0 02176_12 19.381966 37.690587 19.60 nd2 24.6

Table 14: Long period variable stars (ordered by increasing right ascension).

Footnotes

  1. offprints: F. De Marchi

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