Five Long-period Extrasolar Planets in Eccentric orbits from the Magellan Planet Search ProgramBased on observations obtained with the Magellan Telescopes, operated by the Carnegie Institution, Harvard University, University of Michigan, University of Arizona, and the Massachusetts Institute of Technology.

Five Long-period Extrasolar Planets in Eccentric orbits from the Magellan Planet Search Program1

Abstract

Five new planets orbiting G and K dwarfs have emerged from the Magellan velocity survey. These companions are jovian-mass planets in eccentric () intermediate and long-period orbits. HD 86226b orbits a solar metallicity G2 dwarf. The mass of the planet is 1.5 M, the semi-major axis is 2.6 AU, and the eccentricity 0.73. HD 129445b orbits a metal rich G6 dwarf. The minimum mass of the planet is =1.6 M, the semi-major axis is 2.9 AU, and the eccentricity 0.70. HD 164604b orbits a K2 dwarf. The mass is 2.7 M, semi-major axis is 1.3 AU, and the eccentricity is 0.24. HD 175167b orbits a metal rich G5 star. The mass is 7.8 M, the semi-major axis is 2.4 AU, and the eccentricity 0.54. HD 152079b orbits a G6 dwarf. The mass of the planet is 3 M, the semi-major axis is 3.2 AU, and the eccentricity is 0.60.

planetary systems – stars: individual (HD 86226, HD 129445, HD 164604, HD 175167, HD 152079)

1 Introduction

During the past fifteen years, Doppler velocity surveys have uncovered more than 350 extra solar planets around late F, G, K, and M stars within 100 parsecs. This planetary sample covers a wide variety of masses, orbital periods and eccentricites (Butler et al. 2006, Udry & Santos 2007). Most of these planets are jovian-mass with semimajor axes less than 2 AU. Recent discoveries include Neptune-mass and terrestrial-mass planets with orbital periods of days to weeks (Rivera et al. 2005; Udry et al. 2006; Mayor et al. 2009; Vogt et al. 2009; Rivera et al. 2009), and solar system analogs with periods 10 years (Jones et al. 2009; Marcy et al. 2002). While Doppler velocity surveys are increasingly oriented towards finding terrestrial mass planets in small orbits, intermediate and long period companions around nearby stars continue to emerge, and are the primary targets for next generation imaging and interferometric missions.

Since planet formation and evolution theories were in the past based on our solar system, most planetary systems were expected to have circular or low eccentricity orbits. Instead the observed range of exoplanet eccentricities ranges from 0 to 0.93, with a median of e =0.24. The origin of exoplanet eccentricities remains as a basic, unanswered question for planet formation and evolution theory. Planets are believed to form on roughly circular orbits, necessitating a mechanism for pumping up their orbital eccentricities. Possible mechanisms include gravitational scattering by close encounters with other planets on crossing orbits (e.g., Weidenschilling & Marzari 1996; Rasio & Ford 1996), the Kozai (1962) mechanism, where orbital eccentricities and orbital inclinations can be interchanged in an oscillatory manner, and perturbations by other stars (Malmberg & Davies 2009). Disk torques during planet migration have also been advanced, though the eccentricity enhancements obtained are modest at best (e.g., Boss 2005; D’Angelo, Lubow, & Bate 2006; Moorhead & Adams 2008). Recently, the Rossiter-McLaughlin effect has been used to determine high orbital inclinations in highly eccentric planets around binary systems (Winn et al. 2009a) as well as possible retrograde orbits (Winn et al. 2009b, Narita et al. 2009, Anderson et al. 2009). Understanding which dynamical interactions are responsible for these orbital peculiarities will require completing the census of exoplanet eccentricities and inclinations.

In this paper we report the discovery of five eccentric Jupiter-mass planets from the Magellan Planet Search Program. To date the Magellan program has discovered 11 extra-solar planets, including the five reported here (Lopez-Morales et al. 2008; Minniti et al. 2009).

2 The Magellan Planet Search Program

The Magellan Planet Search Program began taking data in Dec 2002 using the MIKE echelle spectrograph (Bernstein et al. 2003), mounted on the 6.5-m Magellan II (Clay) telescope located at Las Campanas Observatory in Chile. Using a 0.35 arc-sec slit, MIKE obtains spectra with a resolution of R 50000, covering the wavelength range from 3900–6200 Å  divided into a red and a blue CCD. An Iodine absorption cell (Marcy & Butler 1992) is mounted in front of the MIKE entrance slit, imprinting the reference Iodine spectrum directly on the incident starlight, providing a wavelength scale and a proxy for the spectrometer point-spread-function (Butler et al. 1996). The Iodine cell is a temperature controlled sealed pyrex tube, such that the column density of Iodine remains constant indefinitely.

The Iodine spectrum (5000 - 6200 Å) falls on the red CCD. The blue CCD captures the CaII H and K lines used to monitor stellar activity. We have monitored a number of stable main sequence stars with spectral types ranging from late F to mid K. Examples of these are shown in Figures 1 and 2 of Minniti et al. 2009. As these figures demonstrate, the Magellan/MIKE system currently achieves measurement precision of 5 m s. The internal measurement uncertainty of our observations is typically 2 to 4 m s, suggesting the Magellan/MIKE system suffers from systematic errors at the 3 to 4 m slevel. To account for this the velocity uncertainties reported in this paper have 3 m sis added in quadrature to the internally derived uncertainties.

The Magellan planet search program is surveying 400 stars ranging from F7 to M5. A histogram of the colors of the Magellan planet search stars is shown in Figure 1. Stars earlier than F7 do not contain enough Doppler information to achieve precision of 5 m s, while stars later than M5 are too faint even for a 6.5-m telescope. The stars in the Magellan program have been chosen to minimize overlap with the AAT 3.9-m and Keck 10-m surveys. Subgiants have not been removed. Stellar jitter for subgiants is small, 5 m/s (Johnson et al. 2007). Stars more than 2 magnitudes above the main sequence have much larger jitter, thus have been removed from the observing list based on Hipparcos distances (Perryman et al. 1997, ESA 1997).

Stars with known stellar companions within 2 arcsec are also removed from the observing list as it is operationally difficult to get an uncontaminated spectrum of a star with a nearby companion. Otherwise there is no bias against observing multiple stars. The Magellan target stars also contain no bias against brown dwarf companions or against metallicity.

3 High-eccentricity Jupiter-mass planets from the Magellan Survey

This paper reports the discovery of five new planet–mass candidates. The stellar properties of the host stars are given in Table 1. The first two columns provide the HD catalog number and the Hipparcos catalog number respectively. The stellar masses are taken from Allende Prieto et al. (1999), [Fe/H] are taken from Holmberg et al. (2007, 2009). Spectral types are taken from the Simbad database.

Figure 2 shows the H line for the 5 stars reported in this paper, in ascending order of B-V. The Sun (bottom) is shown for comparison. Four of these stars are chromospherically quiet. The only star showing activity is the K2 dwarf HD 164604. Active K dwarfs have significantly lower radial-velocity “jitter” than F or G stars (Santos et al. 2000; Wright 2005). The expected photospheric radial velocity jitter for all five of these stars is m/s.

The best-fit orbital parameters of the companions are listed in Table 2. These are all massive planets with large signals (K 35 m s). Due to the sparseness of some of these data sets, the semiamplitudes are poorly constrained. The uncertainties in the orbital parameters are calculated via a Monte Carlo approach as described in Marcy et al. (2005). The individual Magellan Doppler velocity measurements are listed in Tables 3 through 5. The properties of the host stars and of their companions are discussed in turn below.

3.1 Hd 164604

HD 164604 is a K2 V dwarf with and . The Hipparcos parallax (Perryman et al. 1997) gives a distance of 38.46 pc and an absolute visual magnitude . Its metallicity is [Fe/H] (Holmberg et al. 2009).

Eighteen Magellan Doppler velocity observations of HD 164604 spanning 6 years have been made, as shown in Figure 3 and listed in Table 3. The observations span three full orbital periods. The period of the best-fit Keplerian orbit is years, the semi-amplitude is m s, and the eccentricity is . The RMS of the velocity residuals to the Keplerian fit is 7.50 m s. The reduced of the Keplerian fit is 2.7. Assuming a typical mass for a K2V star of M=0.8 M, the minimum mass of the companion is =2.7 M, and the orbital semi-major axis is 1.3 AU.

3.2 Hd 129445

HD 129445 is a G6 V star with and . The Hipparcos parallax (Perryman et al. 1997) gives a distance of 67.61 pc and an absolute visual magnitude, . Its metallicity is [Fe/H] (Holmberg et al. 2009).

Seventeen Magellan Doppler velocity observations of HD 129445 have been obtained, as shown in Figure 4 and listed in Table 4. The observations span a full orbital period. The semi-amplitude of the best-fit Keplerian orbit is m s, the period is years and the eccentricity is . The RMS of the velocity residuals to the Keplerian orbital fit is 7.30 m s. The reduced of the Keplerian orbital fit is 2.5. Assuming a stellar mass of M=0.99 M(Allende Prieto et al. 1999) we derive a minimum mass of =1.6 Mand an orbital semi-major axis of 2.9 AU.

3.3 Hd 86226

HD 86226 is a G2 V star with and . The Hipparcos parallax (Perryman et al. 1997) gives a distance of 42.5 pc and an absolute visual magnitude, . Its metallicity is [Fe/H] (Holmberg et al. 2009).

Thirteen Magellan Doppler velocity observations have been made of HD 86226 over 6.5 years, as shown in Figure 5 and listed in Table 5. These observations span a full orbital period. The best-fit Keplerian orbit to the Magellan data yields a period years, a semi-amplitude () of 37 m s, and an eccentricity . The RMS of the velocity residuals to the Keplerian orbital fit is 6.27 m s. The reduced of the Keplerian orbital fit is 1.82. Given the stellar mass M=1.02 M(Allende Prieto et al. 1999), the minimum mass of the planet is =1.5 Mwith an orbital semi-major axis of 2.6 AU.

3.4 Hd 175167

HD 175167 is a G5 IV/V star with and . The Hipparcos parallax (Perryman et al. 1997) gives a distance of 67.02 pc and an absolute visual magnitude, , consistent with early evolution off the main sequence. Its metallicity is [Fe/H] (Holmberg et al. 2009).

Thirteen Magellan Doppler velocity observations have been made of HD 175167 spanning 5 years, as shown in Figure 6 and listed in Table 6. These observations span a full orbital period. The best-fit Keplerian orbit to the Magellan data yields a period years, a semi-amplitude () of 161 m s, and an eccentricity . The RMS of the velocity residuals to the Keplerian orbital fit is 6.91 m s. The reduced of the Keplerian orbital fit is 2.7. Given the stellar mass M=1.102 M(Allende Prieto et al. 1999), the minimum mass of the planet is =7.8 Mwith an orbital semi-major axis of 2.4 AU.

3.5 Hd 152079

HD 152079 is a G6 dwarf with and . The Hipparcos parallax (Perryman et al. 1997) gives a distance of 85.17 pc and an absolute visual magnitude, . Its metallicity is [Fe/H] (Holmberg et al. 2009).

Fifteen Magellan Doppler velocity observations have been made of HD 152079 over 5.7 years, as shown in Figure 7 and listed in Table 7. The best-fit Keplerian to the Magellan data yields a period years, a semi-amplitude () of 58 m s, and an eccentricity . The RMS of the velocity residuals to the Keplerian orbital fit is 3.58 m s. The reduced of the Keplerian orbital fit is 0.8. Given the stellar mass M=1.03 M(Allende Prieto et al. 1999), the minimum () mass of the planet is =3.0 , with a semi-major axis of 3.2 AU.

4 Discussion

This paper reports the detection of five companions using Magellan/MIKE that have not been previously published. These candidates are high-eccentricity long-period jovian mass and larger planets orbiting nearby G and K dwarfs with metallicities ranging from [Fe/H]=-0.18 to [Fe/H]=0.19.

To date, there are 273 well characterized known extrasolar planets, which show a wide range of eccentricities, from circular to about 0.9 with a median eccentricity of 0.24, contrary to what it was expected before the first exoplanets were discovered. Circular orbits in planets with P20 days can be explained by tidal circularization or orbit decay at periastron, however, the origin of the observed eccentricity distribution is still under debate. Currently, the most compelling explanation for the observed high eccentricities is that they result from planet-planet scattering interactions within systems that contain multiple companions. These interactions presumably take place after the epoch of planet formation, or perhaps during its latter stages. Scattering naturally produces large eccentricities much like the observed distribution, and often results in the ejection of planets (e.g., Moorhead & Adams 2005; Mazari 2005; Ford & Rasio 2008; Juric & Tremaine 2008; Chatterjee et al. 2008). However, since planet-planet scattering alone cannot explain the observed distribution of semimajor axes (scattering cannot move planets far enough inward – Adams & Laughlin 2003), migration due to disk torques is also likely to take place. These disk torques can cause additional changes in eccentricity, including excitation (Goldreich & Sari 2003; Ogilivie & Lubow 2004), damping (e.g., Nelson et al. 2000), or both (Moorhead & Adams 2008). As a result, a complete explanation for the observed eccentricity distribution is still being constructed.

External bodies provide another source of perturbations that can affect orbital eccentricity, even in systems that have reached long-term stability. Such action can be driven by implusive perturbations from passing stars in the birth cluster, or more gradually through distant stellar and/or massive planetary companions (Kozai 1962; Holman et al. 1997; Mazeh et al. 1997; Zakamska & Tremaine 2004; Malmberg & Davies 2009). Simulations of two-body interactions show how interactions between planets can lead to the observed eccentricity distribution (see Juric & Tremaine 2008 and the aforementioned references). However, these simulations predict a slightly larger number of very eccentric () planets than the observed distribution. On the other hand, Malmberg & Davies (2009) simulate planetary systems in binaries and study how the orbital elements can be affected by perturbations exerted by the second component; they find good agreement with the observed distribution of eccentricities for extrasolar planets with semimajor axes between 1 and 6 AU.

Our newly discovered candidates span eccentricities from 0.24 to 0.73, and semi major axis from 1.3 to 3.2 AU. The parent stars of four of the candidates are not part of known binary systems and their RV curves show no other low mass companions. It is worth noting that in the period range days, there are twelve planets with eccentricities higher than 0.5, as shown in figure 8. From these twelve planets, there is just one confirmed to be part of a binary system, and only three of them have eccentricities higher or similar to HD 129445, none of which belong to binary systems. Of the five planets reported in this paper, the lowest eccentricity value corresponds to HD 164604, the only candidate that shows a drift in velocity which indicates the presence of an additional outer body with an orbital period longer than 6 years. In this case, the mechanism described by Malmberg & Davies (2009) could explain the planet’s eccentricity. It is also worth noting that this planet spends part of its orbit in the habitable zone of its parent star ( AU). Ongoing discoveries and further characterization of long period planets will lead to a better understanding of the origin of eccentric planet orbits.

To estimate the feasibility of performing an astrometric follow up of our candidates, we have calculated their astrometric amplitude (218, 132, 117, 470, 168 arcseconds for HD164604, HD129445, HD 86226, HD 175167 and HD 152079 respectively ). Ground-based surveys carried on CCD mosaic cameras mounted on medium-sized telescopes such as CAPSCam (Boss et al. 2009) can now achieve a precision of the order of milliarcsecond(mas), making it is beyond the reach of the astrometric signature of our planetary companions from the ground with current technology. Hipparcos (Perryman 2008) data, provide positions with a precision of 1 mas for fairly bright stars and 0.5 mas for some stars after refinement (van Leeuwen 2007), which is still too low to detect such small signatures. To date, two of these amplitudes could only be reached using HST observations (Benedict et al. 2002c, Benedict et al. 2008). In the future, however, optical space-based astrometric missions such as J-MAPS, Gaia, and SIM will make possible to reach as precision, making plausible to observe such signature.

Imaging follow-up of our candidates with current ground-based 8-m class telescopes or HST would be just as unsuccessful. Due to the required magnitude contrast with the parent star, the minimum angular separation at which 5 Mplanets can be detected around solar-type stars is greater than 0.4 arcsec (Neuhäuser et al. 2005, Biller et al. 2007, Chun et al. 2008, Lagrange et al. 2009, Kasper et al. 2009), while these newly discovered planets, although long period, have angular separations of less than 0.1 arcsec, being too far to be reached by these instruments . They will be, however, main targets of next generation 30-m class telescopes equipped with Adaptive Optics and future interferometers.

These new planets clearly fit an emerging pattern that there is a dearth of planets with semi-major axes of less than 0.5 AU, as seen in figure 9. Presumably this is a signature of migration timescale versus formation timescale as a function of distance from the star, as suggested by Ida & Lin (2004).

We are grateful to the NIST atomic spectroscopy staff, in particular to Dr. Gillian Nave and Dr. Craig Sansonetti, for their expert oversight in calibrating our Iodine cell with the NIST FTS. RPB gratefully acknowledges support from NASA OSS grant NNX07AR4OG. M.L-M. acknowledges support provided by NASA through Hubble Fellowship grant HF-01210.01-A awarded by the STScI, which is operated by the AURA, Inc. for NASA, under contract NAS5-26555. DM and PA are supported by the Basal CATA PFB-06, FONDAP Center for Astrophysics 15010003, and FONDECYT 1090213. The referee, Dr. Michael Endl, made many helpful suggestions that significantly improved this paper. This paper has made use of the Simbad and NASA ADS data bases.
Star Star Spec M V B-V [Fe/H] d
(HD) (Hipp) type (M) (mag) (pc)
164604 88414 K2  V 0.8 9.7 1.39 –0.18 38
129445 72203 G6  V 0.99 8.8 0.756 0.25 67.61
86226 20723 G2  V 1.02 7.93 0.64 –0.04 42.48
175167 20723 G5 IV/V 1.102 8.01 0.751 0.19 67.02
152079 20723 G6  V 1.023 9.18 0.711 0.16 85.17
Table 1: Stellar Properties
Star Period N RMS
(HD) (days) (m s) (degrees) (JD-2450000) (M) (AU) (m s)
16460411 606.4 9 77 32 0.24 0.14 51 23 52674 80 2.7 1.3 1.3 0.05 18 7.50
129445 1840 55 38 6 0.70 0.10 163 15 53093 50 1.6 0.6 2.9 0.2 17 7.30
86226 1534 280 37 15 0.73 0.21 58 50 52240 290 1.5 1.0 2.6 0.4 13 6.27
175167 1290 22 161 55 0.54 0.09 342 9 53598 48 7.8 3.5 2.4 0.05 13 6.91
152079 2097 930 58 18 0.60 0.24 325 37 53193 260 3.0 2.0 3.2 2.1 15 3.58
Table 2: Orbital Parameters
JD RV error
(-2452000) (m s) (m s)
808.7659 -12.1 8.9
918.5317 -6.0 7.6
1130.9311 84.2 4.7
1540.7199 -34.7 3.8
2011.5059 -57.8 5.5
2013.5185 -63.0 4.8
2277.7380 -5.6 4.4
2299.6480 1.5 4.5
2300.6352 -9.1 4.5
2339.5686 21.3 4.8
2399.4832 55.2 4.6
2926.8545 -11.7 4.1
2963.8563 24.3 4.6
2965.8500 12.3 4.8
2993.7397 15.1 4.4
3001.7597 28.1 4.2
3017.7019 35.1 4.4
3019.7039 43.0 4.1
Table 3: Velocities for HD 164604
JD RV error
(-2452000) (m s) (m s)
864.5311 26.1 8.2
1042.8730 -15.2 8.7
1127.8240 -35.8 4.2
1480.8541 15.7 5.7
1574.5786 22.5 4.8
1575.5511 29.4 4.4
1872.6777 43.7 4.2
2217.7257 33.3 4.3
2277.5928 37.5 4.8
2299.4993 31.6 4.3
2501.8506 44.2 4.1
2522.8417 32.9 4.4
2925.8091 -31.9 3.9
2963.7305 -40.3 4.2
2993.6537 -10.8 4.0
3001.6458 -21.4 4.2
3017.6200 -14.4 3.9
Table 4: Velocities for HD 129445
JD RV error
(-2452000) (m s) (m s)
626.8679 -24.6 7.5
663.7551 -11.1 5.1
1041.6735 -12.4 6.9
1128.5597 2.4 4.2
1455.6305 11.5 4.6
1784.7926 20.4 4.8
2583.6051 -4.7 4.2
2843.8112 -1.5 6.3
2925.6391 11.9 4.2
2963.5403 11.3 4.0
2994.5061 11.9 4.1
3001.4805 9.4 4.5
3019.4585 19.6 4.2
Table 5: Velocities for HD 86226
JD RV error
(-2453000) (m s) (m s)
189.7359 -140.3 4.2
190.7340 -138.4 4.3
191.7523 -135.6 4.4
254.5236 -124.5 4.2
654.5074 146.1 4.3
656.5134 152.6 4.0
1217.9281 -124.1 4.5
1339.6070 -137.3 4.3
1725.6182 -73.1 3.8
1965.8675 121.6 4.2
1993.7656 72.3 4.1
2001.7759 81.9 4.3
2017.7389 49.1 3.9
Table 6: Velocities for HD 175167
JD RV error
(-2452000) (m s) (m s)
917.4972 -24.3 6.2
1542.6649 22.5 3.3
1872.8022 -8.5 2.5
1987.5436 -10.3 2.8
1988.5202 -12.6 2.7
2190.8274 -13.7 2.9
2277.6950 -19.7 3.4
2299.6134 -19.6 3.3
2725.5353 -35.1 2.6
2925.9161 -29.2 2.4
2963.7753 -22.6 2.7
2993.7093 -27.5 2.4
3001.7291 -25.3 2.9
3017.6624 -28.5 2.4
3019.6938 -22.5 2.2
Table 7: Velocities for HD 152079
Figure 1: B-V histogram of Magellan Planet Search Stars. The distribution peaks around sun-like stars and diminishes for later spectral types. There is a secondary peak in the distribution around B-V = 1.35, reflecting our bias toward adding the nearest M dwarfs.
Figure 2: Ca II H line cores for the five target G dwarfs in ascending order of .The HD catalog number of each star is shown along the right edge. The Sun is shown for comparison.
Figure 3: Doppler velocities for HD 164604 (K2 V). The solid line is a Keplerian orbital fit with a period of 1.66 years, a semi-amplitude of 77.4 m s, and an eccentricity of 0.24, yielding a minimum companion mass () of 2.7 MṪhe RMS of the Keplerian fit is 7.50 m s. An additional linear trend of -15.9 m sper year provides evidence for a massive outer companion with a period greater than 7 years and a semiamplitude greater than 50 m s.
Figure 4: Doppler velocities for HD 129445 (G6 V). The solid line is a Keplerian orbital fit with a period of 5.04 years, a semi-amplitude of 38 m s, and an eccentricity of 0.70, yielding a minimum () companion mass of 1.6 MṪhe RMS of the Keplerian fit is 7.30 m s.
Figure 5: Doppler velocities for HD 86226 (G2 V). The solid line is a Keplerian orbital fit with a period of 4.20 years, a semi-amplitude of 37 m s, and an eccentricity of 0.73, yielding a minimum () of 1.5 M for the companion. The RMS of the Keplerian fit is 6.27 m s.
Figure 6: Doppler velocities for HD 175167 (G5 IV/ V). The solid line is a Keplerian orbital fit with a period of 3.53 years, a semi-amplitude of 161 m s, and an eccentricity of 0.54, yielding a minimum () companion mass of 7.8 MṪhe RMS of the Keplerian fit is 6.91 m s.
Figure 7: Doppler velocities for HD 152079 (G6 V). The solid line is a Keplerian orbital fit with a period of 5.04 years, a semi-amplitude of 33.1 m s, and an eccentricity of 0.56, yielding a minimum () of 3.0 M for the companion. The RMS of the Keplerian fit is 3.58 m s.
Figure 8: Eccentricities vs. orbital period of known extra-solar planets, where the planets reported in this paper are in filled symbols. Different symbols denote different mass ranges. Note that four of the planets announced in this paper have eccentricities higher than 0.5.
Figure 9: Semimajor axis (a) versus Msini. All low-mass companions discovered by the Magellan Planet Search Program are highlighted as filled, blue circles.

Footnotes

  1. affiliation: Based on observations obtained with the Magellan Telescopes, operated by the Carnegie Institution, Harvard University, University of Michigan, University of Arizona, and the Massachusetts Institute of Technology.
  2. affiliation: Department of Astronomy, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile
  3. affiliation: Department of Terrestrial Magnetism, Carnegie of Washington, 5241 Broad Branch Road NW, Washington D.C. USA 20015-1305
  4. affiliation: Department of Astronomy, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile
  5. affiliation: Department of Terrestrial Magnetism, Carnegie of Washington, 5241 Broad Branch Road NW, Washington D.C. USA 20015-1305
  6. affiliation: Hubble Fellow
  7. affiliation: Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA USA 91101
  8. affiliation: Astronomy Department, University of Michigan, Ann Arbor, MI USA 48109
  9. affiliation: Department of Terrestrial Magnetism, Carnegie of Washington, 5241 Broad Branch Road NW, Washington D.C. USA 20015-1305
  10. affiliation: Department of Terrestrial Magnetism, Carnegie of Washington, 5241 Broad Branch Road NW, Washington D.C. USA 20015-1305
  11. Additional Velocity Slope is -15.9 2.9 m sper yr.

References

  1. Adams, F. C. & Laughlin, G. 2003, Icarus, 163, 290
  2. Allende Prieto, C. & Lamber, D. L. 1999, A&A, 352, 555
  3. Anderson, D. R., Hellier, C., Gillon, M., Triaud, A. H. M. J., Smalley, B., Hebb, L., Collier Cameron, A., Maxted, P. F. L., Queloz, D., West, R. G., Bentley, S. J., Enoch, B., Horne, K., Lister, T. A., Mayor, M., Parley, N. R., Pepe, F., Pollacco, D., SŽgransan, D., Udry, S., Wilson, D. M. 2009, ApJ, Accepted
  4. Benedict, G. F., McArthur, B. E., Forveille, T., Delfosse, X., Nelan, E., Butler, R. P., Spiesman, W., Marcy, G., Goldman, B., Perrier, C., Jefferys, W. H., Mayor, M. 2002 ApJ, 581, 115
  5. Benedict, G. F., McArthur, B. E., Forveille, Bean,J. 2008 IAUS, 248, 23
  6. Bernstein, R., Shectman, S. A., Gunnels, S. M., Mochnacki, S., Athey, A. E. 2003, SPIE, 4841, 1694
  7. Biller, B. A.; Close, L. M.; Masciadri, E.; Nielsen, E.; Lenzen, R.; Brandner, W.; McCarthy, D.; Hartung, M.; Kellner, S.; Mamajek, E.; Henning, T.; Miller, D.; Kenworthy, M.; Kulesa, C. 2007 ApJ, 173, 143
  8. Boss, A. P 2005, ApJ, , 629, 535
  9. Boss, A. P, Weinberger, A.J, Anglada-Escudé, G., Thompson, I., Burey, G., Birk, C., Pravdo, S., Shaklan, S., Gatewood, G. D., Majewski, S.R., Patterson, R. 2009 PASP, , 121, 1218
  10. Butler, R. P. Marcy, G. W. Williams, E. McCarthy, C. Dosanjh, P. & Vogt, S. S. 1996, PASP, 108, 500
  11. Butler, R. P. , Wright, J.  T., Marcy, G.  W., Fischer, D.  A., Vogt, S.  S., Tinney, C.  G., Jones, H.  R.  A.; Carter, B.  D., Johnson, J.  A., McCarthy, C., Penny, A.  J. 2006 ApJ, 646, 505.
  12. Chatterjee, S., Ford, E.  B., Matsumura, S., Rasio, F.  A. 2008 ApJ, 686, 580C.
  13. Chun, M., Toomey, D., Wahhaj, Z., Biller, B., Artigau, E., Hayward, T., Liu, M., Close, L., Hartung, M., Rigaut, F., Ftaclas, C. 2008 SPIE, 7015, 49.
  14. D’Angelo, G., Lubow, S. H., & Bate, M. R. 2006, ApJ, 652, 1698.
  15. ESA 1997, The Hipparcos and Tycho Catalogues (ESA SP-1200).
  16. Ford, E. B. & Rasio, F. A. 2008, ApJ, 686, 621
  17. Goldreich, P., & Sari, R. 2003, ApJ, 585, 1024.
  18. Holmberg, J. Nordstršm, B. & Andersen, J. 2009, ApJ, 501, 941.
  19. Holman, M., Touma, J., Tremaine, S. 1997, Nature, 386, 254.
  20. Ida, S. & Lin, D. N. C., 2004, ApJ, 604, 388.
  21. Johnson, J. A., Fischer, D. A., Marcy, G. W., Wright, J. T., Driscoll, P., Butler, R. P., Hekker, S., Reffert, S., Vogt, S. S. 2007, ApJ, 665, 785.
  22. Jones, H. R. A. et al. 2009, MNRAS, submitted.
  23. Jurić, M. & Tremaine, S. 2008, ApJ, 686, 603.
  24. Kasper, M., Amico, P., Pompei, E., Ageorges, N.,Apai, D., Argomedo, J., Kornweibel, N., Lidman, C. 2009, Msngr, 137, 8K.
  25. Kozai, Y. 1962, AJ, 67, 591.
  26. López-Morales,M. , Butler, R.P., Fischer,D.A., Minniti, D., Shectman, S., Takeda, G., Adams, F.C., Wright, J.T., Arriagada,P. 2008, AJ,136, 1901.
  27. Lagrange, A.-M., Gratadour, D., Chauvin, G., Fusco, T., Ehrenreich, D., Mouillet, D., Rousset, G., Rouan, D., Allard, F., Gendron, ƒ., Charton, J., Mugnier, L., Rabou, P., Montri, J., Lacombe, F. 2009, A&A,493, 21.
  28. Malmberg. D., & Davies, M. B. 2009, MNRAS, 394, L26
  29. Marcy, G. W. & Butler, R. P. 1992, PASP, 104, 270.
  30. Marcy, G. W., Butler, R. P., Fischer, D.  A., Laughlin, G., Vogt, S.S., Henry, G.W., Pourbaix, D. 2002, ApJ, 581, 1375.
  31. Marcy, G. W., Butler, R. P., Vogt, S.S., Fischer, D.  A., Henry, G.W., Laughlin, G., Wright, J. T., Johnson, J. A. 2005, ApJ, 619, 570.
  32. Mayor, M., Bonfils, X., Forveille, T., Delfosse, X., Udry, S., Bertaux, J. L., Beust, H., Bouchy, F., Lovis, C., Pepe, F., Perrier, C., Queloz, D., Santos, N.  C. 2009, A&A, 507, 487.
  33. Mazeh, T., Mayor, M., Latham, D. W. 1997, ApJ, 478, 367.
  34. Minniti, D., Butler, R. P., L—pez-Morales, M., Shectman, S. A., Adams, F. C., Arriagada, P., Boss, A. P., Chambers, J. E. 2009, ApJ, 693, 1424.
  35. Moorhead, A. V., & Adams, F. C. 2005, Icarus, 178, 517.
  36. Moorhead, A. V., & Adams, F. C. 2008, Icarus, 193, 475
  37. Narita, N., Sato, B., Hirano, T., Tamura, Motohide, 2009, PASJ, 61, 35
  38. Nelson, R. P., Papaloizou, J.C.B., Masset, F., & Kley, W. 2000, MNRAS, 318, 18
  39. Neuhäuser, R., Guenther, E. W., Wuchterl, G., Mugrauer, M., Bedalov, A., and Hauschildt, P. H. 2005, A&A, 435, L13
  40. Ogilvie, G. I., & Lubow, S. H. 2003, ApJ, 587, 398
  41. Perryman, M. A. C. et al. 1996, A&A, 310, L21.
  42. Perryman, M. A. C. et al. 1997, A&A, 323, L49. The Hipparcos Catalog
  43. Rasio, F. A., & Ford, E. B. 1996, Science, 274, 954
  44. Rivera, E. J., Lissauer, J. J., Butler, R. P., Marcy, G. W., Vogt, S. S., Fischer, D. A., Brown, T. M., Laughlin, G., Henry, G. W. 2005, ApJ, 634,625
  45. Rivera, E., Butler, R. P., Vogt, S. S., Laughlin, G., Henry, G., Mersciari S. 2009, ApJ, submitted.
  46. Santos, N. C., Mayor, M., Naef, D., Pepe, F., Queloz, D., Udry, S., Blecha, A. 2000, A&A, 361, 265.
  47. Udry, S. Mayor, M. Benz, W. Bertaux, J.-L. Bouchy, F. Lovis, C. Mordasini, C. Pepe, F. Queloz, D. Sivan, J.-P. 2006, A&A,447, 361.
  48. Udry, S. & Santos, N. C. 2007, ARA&A, 45, 397
  49. Vogt, S. S. et al. 2009, ApJ, accepted.
  50. Wright, J. T. 2005, PASP, 117, 657
  51. Weidenschilling, S. J., & Marzari, F. 1996, Nature, 384, 619
  52. Winn, J. N. et al. 2009a, ApJ, 703, 2091
  53. Winn, J. N. et al. 2009a, ApJ, 703L, 99
  54. Zakamska, N. L., & Tremaine, S. 2004, AJ, 128, 869
Comments 0
Request Comment
You are adding the first comment!
How to quickly get a good reply:
  • Give credit where it’s due by listing out the positive aspects of a paper before getting into which changes should be made.
  • Be specific in your critique, and provide supporting evidence with appropriate references to substantiate general statements.
  • Your comment should inspire ideas to flow and help the author improves the paper.

The better we are at sharing our knowledge with each other, the faster we move forward.
""
The feedback must be of minimum 40 characters and the title a minimum of 5 characters
   
Add comment
Cancel
Loading ...
233800
This is a comment super asjknd jkasnjk adsnkj
Upvote
Downvote
""
The feedback must be of minumum 40 characters
The feedback must be of minumum 40 characters
Submit
Cancel

You are asking your first question!
How to quickly get a good answer:
  • Keep your question short and to the point
  • Check for grammar or spelling errors.
  • Phrase it like a question
Test
Test description