WASP-South transiting exoplanets

# WASP-South transiting exoplanets: WASP-130b, WASP-131b, WASP-132b, WASP-139b, WASP-140b, WASP-141b & WASP-142b

Coel Hellier, D.R. Anderson, A. Collier Cameron, L. Delrez, M. Gillon,E. Jehin, M. Lendl, P.F.L. Maxted, M. Neveu-VanMalle, F. Pepe, D. Pollacco, D. Queloz, D. Ségransan, B. Smalley, J. Southworth, A.H.M.J. Triaud, S. Udry, T. Wagg & R.G. West
Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK
SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, Fife, KY16 9SS, UK
Institut d’Astrophysique et de Géophysique, Université de Liège, Allée du 6 Août, 17, Bat. B5C, Liège 1, Belgium
Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, 8042, Graz, Austria
Observatoire astronomique de l’Université de Genève 51 ch. des Maillettes, 1290 Sauverny, Switzerland
Cavendish Laboratory, J J Thomson Avenue, Cambridge, CB3 0HE, UK
Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK
Institute of Astronomy, University of Cambridge, Cambridge, CB3 0HA, UK
date
###### Abstract

We describe seven exoplanets transiting stars of brightness = 10.1 to 12.4. WASP-130b is a “warm Jupiter” having an orbital period of 11.6 d around a metal-rich G6 star. Its mass and radius (1.23 0.04 M; 0.89 0.03 R) support the trend that warm Jupiters have smaller radii than hot Jupiters. WASP-131b is a bloated Saturn-mass planet (0.27 M; 1.22 R). Its large scale height and bright ( = 10.1) host star make it a good target for atmospheric characterisation. WASP-132b (0.41 M; 0.87 R) is among the least irradiated and coolest of WASP planets, having a 7.1-d orbit around a K4 star. WASP-139b is a “super-Neptune” akin to HATS-7b and HATS-8b, being the lowest-mass planet yet found by WASP (0.12 M; 0.80 R). The metal-rich K0 host star appears to be anomalously dense, akin to HAT-P-11. WASP-140b is a 2.4-M planet in an eccentric () 2.2-d orbit. The planet’s radius is large (1.4 R), but uncertain owing to the grazing transit ( = 0.93). The 10.4-day rotation period of the K0 host star suggests a young age, and the timescale for tidal circularisation is likely to be the lowest of all known eccentric hot Jupiters. WASP-141b (2.7 M, 1.2 R, = 3.3 d) and WASP-142b (0.84 M, 1.53 R, = 2.1 d) are typical hot Jupiters orbiting metal-rich F stars. We show that the period distribution within the hot-Jupiter bulge does not depend on the metallicity of the host star.

###### keywords:
planetary systems – stars: individual (WASP-130, WASP-131, WASP-132, WASP-139, WASP-140, WASP-141, WASP-142)
pagerange: range

## 1 Introduction

The WASP survey continues to be a productive means of finding giant planets transiting relatively bright stars. WASP discoveries are often prime targets for further study. For example 2016Natur.529...59S devoted 125 orbits of Hubble Space Telescope time to exoplanet atmospheres, of which 6 out of 8 targets were WASP planets. Similarly, 2016PASP..128i4401S propose 12 planets as “community targets” for atmospheric characterisation in Cycle 1 of the James Webb Space Telescope, of which 7 are WASP planets. Ongoing discoveries also increase the census of closely orbiting giant planets, and continue to find planets with novel characteristics.

Here we report seven new transiting giant planets discovered by the WASP-South survey instrument in conjunction with the Euler/CORALIE spectrograph and the robotic TRAPPIST photometer. With 200-mm lenses the eight WASP-South cameras can cover up to half the available sky per year (south of declination +08 and avoiding the crowded galactic plane). This means that the data that led to the current discoveries, accumulated from 2006 May to 2012 Jun, typically includes three seasons of coverage, or more where pointings overlap. Combining multiple years of observation gives sensitivity to longer orbital periods, and this batch of planets includes the longest-period WASP discovery yet, a “warm Jupiter” at 11.6 days.

## 2 Observations

Since the processes and techniques used here are a continuation of those from other recent WASP-South discovery papers (e.g. 2014MNRAS.445.1114A; 2014MNRAS.440.1982H; 2016A&A...591A..55M) we describe them briefly. The WASP camera arrays (2006PASP..118.1407P) tile fields of with a typical cadence of 10 mins, using 200mm f/1.8 lenses backed by 2k2k Peltier-cooled CCDs. Using transit-search algorithms (2007MNRAS.380.1230C) we trawl the accumulated multi-year lightcurves for planet candidates, which are then passed to the 1.2-m Euler/CORALIE spectrograph (e.g. 2013A&A...551A..80T), for radial-velocity observations, and to the robotic 0.6-m TRAPPIST photometer, which resolves candidates which are blended in WASP’s large, 14, pixels. TRAPPIST (e.g. 2013A&A...552A..82G) and EulerCAM (e.g. 2012A&A...544A..72L) then obtain higher-quality photometry of newly confirmed planets. For one system reported here, WASP-139, we have also obtained radial velocities using the HARPS spectrometer on the ESO 3.6-m (2003Msngr.114...20M). A list of our observations is given in Table 1 while the radial velocities are listed in Table A1.

## 3 The host stars

We used the CORALIE spectra to estimate spectral parameters of the host stars using the methods described in 2013MNRAS.428.3164D. We used the H line to estimate the effective temperature (), and the Na i D and Mg i b lines as diagnostics of the surface gravity (). The Iron abundances were determined from equivalent-width measurements of several clean and unblended Fe i lines and are given relative to the Solar value presented in 2009ARA&A..47..481A. The quoted abundance errors include that given by the uncertainties in and , as well as the scatter due to measurement and atomic data uncertainties. The projected rotation velocities () were determined by fitting the profiles of the Fe i lines after convolving with the CORALIE instrumental resolution ( = 55 000) and a macroturbulent velocity adopted from the calibration of 2014MNRAS.444.3592D.

The parameters obtained from the analysis are given in Tables 2 to 8. Gyrochronological age estimates are given for three stars, derived from the measured  and compared to values in 2007ApJ...669.1167B; for the other stars no sensible constraint is obtained. Lithium age estimates come from values in 2005A&A...442..615S. We also list proper motions from the UCAC4 catalogue (2013AJ....145...44Z).

We searched the WASP photometry of each star for rotational modulations by using a sine-wave fitting algorithm as described by 2011PASP..123..547M. We estimated the significance of periodicities by subtracting the fitted transit lightcurve and then repeatedly and randomly permuting the nights of observation. We found a significant modulation in WASP-140 (see Section 10) and a possible modulation in WASP-132 (Section 8) and report upper limits for the other stars.

## 4 System parameters

The CORALIE radial-velocity measurements (and the HARPS data for WASP-139) were combined with the WASP, EulerCAM and TRAPPIST photometry in a simultaneous Markov-chain Monte-Carlo (MCMC) analysis to find the system parameters. CORALIE was upgraded in 2014 November, and so we treat the RV data before and after that time as independent datasets, allowing a zero-point offset between them (the division is indicated by a short horizontal line in Table A1). For more details of our methods see 2007MNRAS.375..951C. The limb-darkening parameters are noted in each Table, and are taken from the 4-parameter non-linear law of 2000A&A...363.1081C.

For WASP-140b the orbital eccentricity is significant and was fitted as a free parameter. For the others we imposed a circular orbit since hot Jupiters are expected to circularise on a timescale less than their age, and so adopting a circular orbit gives the most likely parameters (see, e.g., 2012MNRAS.422.1988A).

The fitted parameters were , , , , , , where is the epoch of mid-transit, is the orbital period, is the fractional flux-deficit that would be observed during transit in the absence of limb-darkening, is the total transit duration (from first to fourth contact), is the impact parameter of the planet’s path across the stellar disc, and is the stellar reflex velocity semi-amplitude.

The transit lightcurves lead directly to stellar density but one additional constraint is required to obtain stellar masses and radii, and hence full parametrisation of the system. As with other recent WASP discovery papers, we compare the derived stellar density and the spectroscopic effective temperature and metallicity to a grid of stellar models, as described in 2015A&A...575A..36M. We use an MCMC method to calculate the posterior distribution for the mass and age estimates of the star. The stellar models were calculated using the garstec stellar evolution code (2008Ap&SS.316...99W) and the methods used to calculate the stellar model grid are described in 2013MNRAS.429.3645S.

For each system we list the resulting parameters in Tables 2 to 8 and show the data and models in Figures 1 to 14. We generally report 1- error bars on all quantities. For the possible effects of red noise in transit lightcurves and their affect on system parameters see the extensive analysis by 2012AJ....143...81S. We report the comparison to stellar models in Table 9, where we give the likeliest age and the 95% confidence interval, and display the comparison in Fig. 15.

## 5 Wasp-130

WASP-130 is a = 11.1, G6 star with a metallicity of [Fe/H] = +0.26 0.10. The transit of 4.49 0.02 is consistent with the spectroscopic of 4.4 0.1. The evolutionary comparison (Fig. 15) suggests an age of 0.2–7.9 Gyr (consistent with the lithium age estimate of 2 Gyr).

The radial velocities show excess scatter with could be due to magnetic activity, though in this system there is no detection of a rotational modulation in the WASP data. Scatter when folded on the orbital period can also be caused by a longer-term trend, but that is not the case here.

The planet, WASP-130b, has an orbital period of 11.6 days, the longest yet found by WASP-South, and is thus a “warm jupiter”. For comparison, the HATNet and HATSouth projects have cameras at more than one longitude and so are more sensitive to longer periods; their longest-period system is currently HATS-17b at 16.3 d (2016AJ....151...89B).

The mass of WASP-130b is 1.23 0.04 M. In keeping with other longer-period systems (e.g. 2011ApJS..197...12D), but in contrast to many hotter Jupiters, the radius is not bloated (0.89 0.03 R). WASP-130b is thus similar to HATS-17b (1.34 M; 0.78 R; 2016AJ....151...89B), though not quite as compact. Brahm et al. suggest that HATS-17b has a massive metallic core, which they link to the raised metallicity of [Fe/H] = +0.3, which is again similar to that of WASP-130 ([Fe/H] = +0.25).

## 6 Wasp-131

WASP-131 is a = 10.1, G0 star with a metallicity of [Fe/H] = –0.18 0.08. The transit of 4.09 0.03 is consistent with the spectroscopic of 3.9 0.1. The radius is inflated (1.53 R for 1.06 M) and the evolutionary comparison (Fig. 15) suggests an age of 4.5–10 Gyr (consistent with the poorly constrained lithium estimate of between 1 and 8 Gyr).

The planet, WASP-131b, has an orbital period of 5.3 days. It is a Saturn-mass but bloated planet (0.27 M; 1.22 R). The low density of the planet (0.15  0.02 ) and the consequent large scale-height of the atmosphere, coupled with the host-star magnitude of = 10.1, should make WASP-131b a good candidate for atmospheric characterisation.

Low-density, Saturn-mass planets akin to WASP-131b have been seen before. The most similar include WASP-21b (0.28 M; 1.2 R; = 4.3 d; 2010A&A...519A..98B), WASP-39b (0.28 M; 1.3 R; = 4.1 d; 2011A&A...531A..40F), Kepler-427b (0.29 M; 1.2 R; = 10.3 d; 2014A&A...572A..93H) and HAT-P-51b (0.30 M; 1.3 R; = 4.2 d; 2015AJ....150..168H).

## 7 Wasp-132

WASP-132 is a = 12.4, K4 star with a metallicity of [Fe/H] = +0.22 0.13. The transit of 4.61 0.02 is consistent with the spectroscopic of 4.6 0.1. The evolutionary comparison (Fig. 15) gives an age of  0.9 Gyr.

The radial-velocities show excess scatter, which may be due to magnetic activity. There is also a suggestion in Fig. 5 of a possible correlation of the bisector with orbital phase. This is partly due to a possible longer-term trend to both lower radial velocities and bisectors over the span of the observations. The radial velocities decrease by 60 m s over time, though this is unreliable owing to the CORALIE upgrade midway through the dataset. If we analyse the data before and after the upgrade separately we find no significant correlation between the bisector and the radial-velocity value.

A possible rotational modulation with a period of 33 3 d, and an amplitude of 0.4-mmag, is seen in 3 out of 5 seasons of WASP data (Fig. 6), while a possible modulation at half this period is seen in a 4th dataset. This is close to the limit detectable with WASP data (for the other stars we’re quoting upper limits in the range 0.5–1.5 mmag), and so is not fully reliable.

A rotational period of 33 3 d would indicate a gyrochronological age of 2.2 0.3 Gyr (2007ApJ...669.1167B), which is consistent with the above evolutionary estimate. The period would also imply an equatorial velocity of 1.1 0.2 km s, which is consistent with the observed (but poorly constrained)  value of 0.9 0.8 km s.

The planet, WASP-132b, has a low-mass and a modest radius compared to many hot Jupiters (0.41 M; 0.87 R). With an orbital period of 7.1 d around a K4 star it is among the least irradiated of the WASP planets. The equilibrium temperature is estimated at only 763 16 K. Of WASP systems, only WASP-59b (2013A&A...549A.134H), in a 7.9-d orbit around a K5V, has a lower temperature of 670 35 K. HATS-6b (2015AJ....149..166H), in a 3.3-d orbit around an M1V star, is also cooler (713 5 K), but all other cooler gas giants have orbital periods of greater than 10 d.

## 8 Wasp-139

WASP-139 is a = 12.4, K0 star with a metallicity of [Fe/H] = +0.20 0.09. The transit of 4.59 0.06 is consistent with the spectroscopic of 4.5 0.1. The gyrochonological age constraint and the lack of lithium imply a relatively young star of  0.5 Gyr.

The stellar density resulting from the transit analysis (1.8 0.2 ; 0.92 M, 0.80 R) puts the star below the main sequence and is only marginally consistent with the evolutionary models of 2015A&A...575A..36M. The same has been found for HAT-P-11 (2010ApJ...710.1724B) and possibly also for WASP-89 (2015AJ....150...18H). For a discussion of this see 2015A&A...577A..90M, who suggested that such stars might be helium-rich.

The planet, WASP-139b, has a mass of only 0.12 0.02 M, making it the lowest-mass WASP discovery yet. With a radius of 0.80 R, and thus a low density of 0.23 0.04 , the large scale height makes WASP-139b a good target for atmospheric characterisation.

Owing to the small planet mass, and thus the low reflex velocity, we obtained HARPS data in order to better parametrise the system. This included observations of the Rossiter–McLaughlin effect through transit (Fig. 8). If the orbit were aligned, and taking values for the  and impact parameter from Table 5, we’d expect an R–M effect of order 30 m s (e.g. 2007ApJ...655..550G). The HARPS data indicate a much lower value, though owing to the relatively large errors the fit is effectively unconstrained and thus we do not report parameters such as the alignment angle.

WASP-139b is most similar to two recent discoveries by the HATSouth project, HATS-7b (2015ApJ...813..111B) and HATS-8b (2015AJ....150...49B). HATS-7b is a 0.12 M planet with a radius of 0.56 R in a 3.2-d orbit. The host stars are also similar (HATS-7 is a V = 13.3, K dwarf, T = 4985, [Fe/H] = +0.25; HATS-8 is a V = 14.0 G dwarf, T = 5680, [Fe/H] = +0.21; whereas WASP-139 is a V = 12.4 K0 dwarf, T = 5300, [Fe/H] = +0.20). The HATS project have called such systems “super-Neptunes”, and, as now the brightest example, the WASP-139 system will be important for studying such objects.

## 9 Wasp-140

WASP-140A is a = 11.1, K0 star with a metallicity of [Fe/H] = +0.12 0.10. The transit of 4.51 0.04 is higher than the spectroscopic of 4.2 0.1. In such cases we regard the transit value as the more reliable, given the systematic uncertainties in estimates in such spectra (e.g. 2015ApJ...805..126B report discrepancies as big as 0.3 dex).

A second star, WASP-140B, is fainter by 2.01 0.02 magnitudes and is 7.24 0.01 arcsecs from WASP-140 at a position angle of 77.4 0.1 degrees (values from the EulerCAM observation on 2015-09-01 with a filter). The TRAPPIST and EulerCAM transit photometry used a small aperture that excluded this star. The 2MASS colours of WASP-140B ( = 11.09 0.03; = 10.46 0.02; = 10.27 0.03) are consistent with it being physically associated with WASP-140A ( = 9.61 0.03; = 9.24 0.02; = 9.17 0.03), and so it is possible that the two stars form a binary. There are no proper motion values listed for WASP-140B in UCAC4.

The WASP data on WASP-140 show a clear rotational modulation with a period of 10.4 0.1 days and an amplitude varying between 5 and 9 mmag (Fig. 11), implying that it is magnetically active. The WASP aperture includes both stars, so it is not certain which star is the variable, though if it were WASP-140B then the amplitude would have to be 6 times higher, which is less likely. There is also evidence of a star spot in each of the two lowest transit lightcurves in Fig. 9, which would imply that WASP-140A is magentically active.

The 10.4-d rotational period would imply a young gyrochronological age for WASP-140A of 0.42 0.06 Gyr (2007ApJ...669.1167B). This is inconsistent with the evolutionary comparison (Fig. 15), which suggests a likeliest age of 8 Gyr with a lower bound of 1.7 Gyr. This inconsistency suggests that WASP-140A has been spun up by the presence of the massive, closely orbiting planet (see the discussion in 2014MNRAS.442.1844B).

The rotational period equates to an equatorial velocity of 6.3 0.9 km s. Comparing this to the observed  value of 3.1 0.8 km s suggests a misaligned system, with the star’s spin axis at an inclination of 30 15.

The planet WASP-140Ab has a mass of 2.4 M and is in a 2.2-day orbit. The transit is grazing, with an impact parameter of 0.93 . Other WASP planets that are grazing are WASP-67b (2012MNRAS.426..739H; 2014A&A...568A.127M) and WASP-34b (2011A&A...526A.130S). Since it is possible that not all of the planet is transiting the star its radius is ill-constrained at 1.44 R.

### 9.1 WASP-140Ab’s eccentric orbit

The orbit of WASP-140Ab is eccentric with . A Lucy–Sweeney test shows this to be significantly non-zero with % confidence. Being significantly eccentric at an orbital period as short as 2.2 days is unusual in a hot Jupiter. For comparison, WASP-14b (2009MNRAS.392.1532J) also has an eccentric 2.2-day orbital period, but is a much more massive planet at 7.7 M. WASP-89b (2015AJ....150...18H) has an eccentric 3.4-d orbit and is also more massive at 5.9 M.

The circularisation timescale for a hot Jupiter can be estimated from (2006ApJ...649.1004A, eqn 3):

 τcir ≈ 1.6 Gyr×(QP106)×(MPMJup)×(M∗%M$\sun$)−3/2 ×(RPRJup)−5×(a0.05 AU)13/2

Using a value of the quality factor, , of 10 (e.g. 2012arXiv1209.5724S), and the parameters of Table 6, gives a circularisation timescale of 5 Myr. Note, however, the strong dependence on , which is poorly contrained in WASP-140Ab owing to the grazing transit. Pushing up to 10, and taking the parameters at their 1-sigma boundaries to lengthen the timescale allows values of 100 Myr. This is still short compared to the likely age of the host star, and suggests that WASP-140b has only relatively recently arrived in its current orbit.

Comparing to other hot-Jupiters, using the above equation and parameters tabulated in TEPCat (2011MNRAS.417.2166S), we find that WASP-140Ab has the shortest circularisation timescale of all hot Jupiters that are in clearly eccentric orbits (where we adopt a 3 threshold). Using the best-fit parameters of Table 6 for WASP-140Ab, and adopting = 10, gives = 6.6.

A timescale of = 6.1 is obtained for WASP-18b (2009Natur.460.1098H), which has been reported as having a small but significant eccentricity of = 0.008 0.001 (2010A&A...524A..25T). However, this apparent eccentricity might instead be an effect of the tidal bulge on WASP-18, which is the biggest of any known hot-Jupiter system (see 2012MNRAS.422.1761A).

The next shortest timescale is = 6.8 for HAT-P-13b (2009ApJ...707..446B). From Spitzer observations of the planetary occulation, 2016ApJ...821...26B report a significant eccentricity of . In this system, however, the eccentricity of the hot Jupiter HAT-P-13b is likely being maintained by the perturbative effect of HAT-P-13c, a 14 M outer planet in a highly eccentric () 446-day orbit (2010ApJ...718..575W).

The smallest timescale for any other hot Jupiter that is indisputably eccentric is likely that for WASP-14b at = 7.6. This is an order of magnitude longer than that for WASP-140Ab, which implies that WASP-140Ab is unusual. Tidal heating has long been proposed as a possible cause of the inflated radii of many hot Jupiters (e.g. 2013arXiv1304.4121S and references therein), and may help to explain the fact that WASP-140Ab has a bloated radius despite being relatively massive. It will be worth obtaining better transit photometry of WASP-140, in order to better constrain the parameters, and also worth looking for an outer planet that might be maintaining the eccentricity.

It’s also worth noting that short-period, massive and eccentric planets are rare around K stars. WASP-89b is the previously known example, a 6 M planet in a 3.36-d orbit with an eccentricity of 0.192 0.009 around a K3 star (2015AJ....150...18H). The magnetic activity of both stars, WASP-89 and WASP-140A, might be related to the presence of the eccentric, short-period planet (e.g. 2014A&A...565L...1P).

## 10 Wasp-141

WASP-141 is a = 12.4, F9 star with a metallicity of [Fe/H] = +0.29 0.09. The transit of 4.26 0.06 is consistent with the spectroscopic value of 4.20 0.15. The evolutionary comparison (Fig. 15) gives an age estimate of 1.5–5.6 Gyr. This is compatible with the gyrochronological estimate of Gyr and marginally consistent with the lithium age of 5 Gyr.

The planet, WASP-141b is a 2.7 M, 1.2 R planet in a 3.3-d orbit. WASP-141 appears to be a typical hot-Jupiter system.

## 11 Wasp-142

WASP-142A is a = 12.3, F8 star with a metallicity of [Fe/H] = +0.26 0.12. The transit of 4.13 0.04 is consistent with the spectroscopic value of 4.0 0.2. The evolutionary comparison (Fig. 15) gives an age estimate of 2.2–7.0 Gyr. The lithium age is marginally inconsistent at 2 Gyr.

A second star, WASP-142B, is fainter by 1.86 0.01 magnitudes and at 5.11 0.01 arcsecs from WASP-142 at a position angle of 45.7 0.1 degrees (values from an EulerCAM observation on 2014-12-13 with a filter). The 2014 December EulerCAM transit photometry used an aperture including both stars, and we corrected the lightcurve for the dilution in the analysis. The other EulerCAM transit and the two TRAPPIST transits used a smaller photometric aperture excluding the second star.

The 2MASS colours of WASP-142B ( = 13.42 0.04; = 13.03 0.04; = 12.94 0.03) are consistent with it being physically associated with WASP-142A ( = 11.73 0.03; = 11.48 0.03; = 11.44 0.03). UCAC4, however, reports a very different proper motion for WASP-142B (pmRA = –99.1  2.1, pmDec = 98.3  2.2 mas/yr) than for WASP-142A (pmRA = –3.1  3.5, pmDec = 3.7  3.1 mas/yr), which, if reliable, would rule out a physical association.

WASP-142Ab is a bloated planet of sub-Jupiter mass (1.53 R; 0.84 M) in a 2.1-d orbit. Again, WASP-142 is a fairly typical hot-Jupiter system.

## 12 Hot Jupiter period distribution

We take the opportunity to revisit the period distribution of gas giants in close orbits. We have thus taken all planets with masses 0.15–12 M listed in TEPCat, and added the unpublished WASP planets as far as WASP-166b, and plot the cumulatative period distribution in Fig. 16. This figure contains 321 planets out to 22 days, nearly doubling the 163 planets in the similar analysis in 2012MNRAS.426..739H.

The two “breaks” suggested by 2012MNRAS.426..739H at 1.2 d and 2.7 d are still present. The systems with periods 1.2 d are rare, despite having a greater range of inclinations that produce a transit, and despite being the easiest to find in transit surveys. They likely have short lifetimes owing to tidal inspiral. Above 2.7 d the hot-Jupiter “pileup” continues to a more gradual rollover over the range 4–7 d. Above 8 or 9 days the ground-based transit surveys will be less sensitive, and so one should be cautious in interpreting the distribution at longer periods.

2013ApJ...767L..24D analysed the Kepler sample of giant planets and found that the period distribution was strongly dependent on the metallicity of the host star (their Fig. 4). They suggested that the hot-Jupiter bulge is a feature only of metal-rich stars, and that the excess of hot Jupiters relative to longer-period giant planets is not present in a sample with [Fe/H] 0. Note, however, that their analysis depended on the use of KIC metallicities, which come from photometric colours and thus may not be fully reliable (2014ApJ...789L...3D).

Our above sample has very few planets beyond d and so cannot be used to test the 2013ApJ...767L..24D result itself. We can, however, address the related question of whether the period distribution within the hot-Jupiter bulge has a metallicity dependence, as might be the case if the formation of hot Jupiters depends strongly on metallicity. We thus take all the planets in our sample with host-star metallicities listed in TEPCat, plus those in this paper, noting that these metallicities come from spectroscopic analyses of relatively bright host stars.

We then divide the sample into metallicities above and below solar (192 and 79 planets, respectively). The two distributions are compared (after normalising them) in Fig. 16. A K–S test says that they are not significantly different, with a 40% chance of being drawn from the same distribution. Thus, there does not appear to be a metallicity dependence of the period distribution within the hot-Jupiter bulge, though the discovery of more longer-period giant planets is needed to test the 2013ApJ...767L..24D result itself.

## 13 Conclusions

The ongoing WASP surveys continue to discover novel objects which push the bounds of known exoplanets (e.g. the rapid circularisation timescale of WASP-140b) along with planets transiting bright stars which are good targets for atmospheric characterisation (e.g. WASP-131b, with a = 10.1 star). We also present the longest-period (WASP-130b), lowest-mass (WASP-139b) and second-coolest (WASP-132b) of WASP-discovered planets. We also demonstrate the power of WASP photometry in the possible detection of a 0.4-mmag rotational modulation of the star WASP-132.

## Acknowledgements

WASP-South is hosted by the South African Astronomical Observatory and we are grateful for their ongoing support and assistance. Funding for WASP comes from consortium universities and from the UK’s Science and Technology Facilities Council. The Euler Swiss telescope is supported by the Swiss National Science Foundation. TRAPPIST is funded by the Belgian Fund for Scientific Research (Fond National de la Recherche Scientifique, FNRS) under the grant FRFC 2.5.594.09.F, with the participation of the Swiss National Science Fundation (SNF). We acknowledge use of the ESO 3.6-m/HARPS under program 094.C-0090.

## References

 BJD – 2400 000 RV σRV Bisector (UTC) (km s−1) (km s−1) (km s−1) WASP-131: 56694.86288 −19.6343 0.0055 0.0340 56713.72539 −19.6948 0.0071 0.0276 56723.89584 −19.6926 0.0063 0.0166 56724.87344 −19.6800 0.0058 0.0354 56726.70668 −19.6420 0.0057 0.0422 56744.91236 −19.6899 0.0059 0.0347 56745.85830 −19.6902 0.0061 0.0186 56746.62422 −19.6705 0.0061 0.0149 56748.84647 −19.6348 0.0059 0.0442 56749.72097 −19.6652 0.0054 0.0173 56769.58299 −19.6365 0.0056 0.0183 56809.72416 −19.6991 0.0058 0.0322 56810.71410 −19.6629 0.0072 0.0371 56811.72508 −19.6332 0.0070 0.0233 56830.66400 −19.6960 0.0064 0.0280 56839.62346 −19.6526 0.0067 0.0218 56864.52557 −19.6406 0.0056 0.0354 57055.82138 −19.6531 0.0059 0.0170 57071.84521 −19.6406 0.0065 0.0135 57110.88171 −19.6367 0.0077 0.0145 57139.77294 −19.6875 0.0085 0.0156 57194.63654 −19.6207 0.0080 0.0252 57458.77449 −19.6801 0.0055 0.0431 WASP-132: 56717.73665 31.1460 0.0103 0.0087 56749.88330 31.0358 0.0111 0.0298 56772.83833 31.0369 0.0099 0.0359 56779.80482 31.0630 0.0130 −0.0239 56781.68823 31.1323 0.0116 −0.0406 56782.75296 31.1388 0.0107 0.0058 56803.73759 31.0888 0.0232 0.0482 56808.75158 31.0784 0.0157 0.0360 56810.73750 31.1109 0.0153 0.0722 56811.69973 31.0846 0.0132 0.0369 56813.73159 31.0472 0.0281 0.0266 56814.74102 31.0197 0.0139 −0.0298 56830.68796 31.0877 0.0141 0.0027 56833.58020 31.0764 0.0133 0.0523 56840.60592 31.0667 0.0196 0.0671 56853.53751 31.1467 0.0504 0.0238 56855.61273 31.0228 0.0127 0.0198 56856.59422 31.0223 0.0105 0.0341 56880.53254 31.0585 0.0151 −0.0006 56888.54232 31.0888 0.0133 0.0140 56889.52621 31.0884 0.0110 0.0412 56910.48465 31.0966 0.0222 0.0143 57031.85994 31.0528 0.0150 0.0006 57072.87336 31.0326 0.0118 −0.0502 57085.80107 30.9265 0.0128 −0.0155 57086.74260 30.9483 0.0131 −0.0098 57111.67974 30.9845 0.0173 0.0246 57112.85851 30.9697 0.0291 −0.0224 57114.83854 30.9679 0.0212 −0.0530 57139.68574 31.0283 0.0215 −0.0124 57194.67667 31.0018 0.0278 −0.0526 57405.83694 30.9468 0.0130 −0.0141 57412.84526 30.9293 0.0176 −0.0042 57426.84822 30.9744 0.0103 0.0005 57428.82227 30.9898 0.0084 −0.0045 57455.88964 30.9471 0.0127 −0.0609 Bisector errors are twice RV errors
 BJD – 2400 000 RV σRV Bisector (UTC) (km s−1) (km s−1) (km s−1) WASP-139: CORALIE 54763.67767 −13.0496 0.0201 0.0220 54766.72371 −13.0095 0.0157 −0.0082 54776.79057 −12.9875 0.0254 0.0412 56211.82564 −12.9931 0.0143 −0.0039 56220.76495 −13.0409 0.0129 −0.0270 56516.89696 −13.0298 0.0145 0.0481 56577.69538 −13.0346 0.0114 0.0167 56578.87291 −12.9959 0.0105 0.0434 56581.87217 −13.0236 0.0101 0.0045 56623.78855 −13.0314 0.0111 0.0041 56629.59554 −13.0451 0.0116 −0.0148 56873.90932 −13.0314 0.0189 0.0315 56874.84054 −12.9882 0.0137 −0.0056 56876.88875 −13.0143 0.0148 0.0299 56877.79318 −13.0013 0.0168 −0.0149 56879.89171 −12.9778 0.0143 0.0597 56952.66033 −12.9785 0.0170 0.0036 56987.55377 −12.9923 0.0413 0.0157 56988.58979 −12.9637 0.0170 −0.0202 57038.59542 −12.9972 0.0184 0.0707 57085.52067 −13.0019 0.0154 0.0112 57286.88716 −13.0439 0.0340 −0.0055 57336.69857 −13.0050 0.0302 −0.0803 57367.71629 −12.9748 0.0168 −0.0425 WASP-139: HARPS 56927.79489 −12.9888 0.0064 −0.0186 56929.83816 −12.9931 0.0058 −0.0043 56948.67436 −13.0052 0.0057 0.0002 56949.65985 −13.0067 0.0062 0.0179 56951.74760 −12.9814 0.0037 0.0021 56952.74043 −12.9857 0.0041 −0.0181 56953.76702 −12.9860 0.0034 0.0121 56955.70180 −13.0079 0.0029 0.0066 56957.86492 −12.9971 0.0097 −0.0048 56958.72499 −12.9856 0.0050 0.0157 56959.70035 −12.9962 0.0044 0.0032 56959.71448 −12.9984 0.0048 0.0080 56959.72874 −12.9900 0.0043 0.0126 56959.74518 −12.9994 0.0034 0.0066 56959.76257 −12.9952 0.0048 0.0093 56959.78116 −12.9929 0.0046 0.0014 56959.79786 −12.9955 0.0047 0.0101 56959.81611 −12.9907 0.0054 −0.0037 56959.83386 −12.9970 0.0057 0.0112 56959.85175 −12.9952 0.0060 −0.0198 56959.86897 −13.0020 0.0067 0.0217 56997.70376 −13.0057 0.0039 0.0043 56999.72988 −12.9820 0.0039 0.0058 57032.61218 −13.0151 0.0055 −0.0028 57033.58272 −12.9941 0.0083 0.0073 57034.60223 −12.9789 0.0062 0.0048 57035.58562 −12.9898 0.0055 0.0182 Bisector errors are twice RV errors
 BJD – 2400 000 RV σRV Bisector (UTC) (km s−1) (km s−1) (km s−1) WASP-140: 56920.76077 2.5349 0.0098 0.0133 56930.82132 1.7340 0.0078 0.0621 56931.82218 2.5133 0.0072 0.0327 56936.79830 2.3340 0.0080 −0.0200 56950.84894 1.7484 0.0075 0.0393 56953.78131 2.1478 0.0094 0.0583 56955.77226 1.8930 0.0080 −0.0048 56956.82473 2.4086 0.0108 0.0331 56959.76870 1.7695 0.0083 0.0436 56965.86872 2.3001 0.0075 0.0341 56978.70617 2.5095 0.0120 0.0083 56979.66055 1.9375 0.0122 0.0167 56980.76045 2.3070 0.0108 0.0344 56983.78948 2.2687 0.0101 −0.0310 56984.69862 1.7913 0.0094 −0.0291 56987.58015 2.4201 0.0165 0.0227 57004.59553 1.7625 0.0100 −0.0143 57019.69293 2.1414 0.0129 0.0144 57039.60065 2.3649 0.0105 0.0533 57060.61575 1.7552 0.0100 0.0184 57085.55015 1.9915 0.0094 0.0263 57339.77164 1.8358 0.0124 0.0171 57369.68260 2.1369 0.0230 0.0419 Bisector errors are twice RV errors
 BJD – 2400 000 RV σRV Bisector (UTC) (km s−1) (km s−1) (km s−1) WASP-141: 56955.84534 34.1669 0.0320 0.0300 56965.81124 34.1291 0.0208 −0.0239 56990.59092 33.5216 0.0406 0.0124 56993.81477 33.5438 0.0472 −0.0758 57011.63059 33.9947 0.0268 0.0174 57012.68022 33.9561 0.0401 0.0222 57014.72766 33.8971 0.0300 0.0412 57016.66733 33.6264 0.0293 −0.0376 57033.72918 33.4964 0.0310 0.0756 57039.62726 33.7132 0.0392 −0.0572 57040.67281 33.5825 0.0376 0.0010 57041.67337 34.1062 0.0497 0.0222 57065.65032 34.0360 0.0361 0.0875 57118.48484 34.0519 0.0695 0.0801 57291.83917 33.5517 0.1031 0.1949 57319.74513 34.0872 0.0708 −0.1402 57333.80278 33.9814 0.0534 −0.0012 57371.75720 33.6182 0.0412 −0.0456 WASP-142: 56744.53717 47.2374 0.0201 0.0793 56747.54086 47.0456 0.0262 0.0789 56771.61011 47.1023 0.0260 0.0468 56772.58229 47.0722 0.0258 0.0260 56779.61261 47.2061 0.0321 −0.0846 56803.51322 47.1629 0.0277 0.0273 56987.86072 46.9854 0.0584 −0.1158 56996.81308 47.1962 0.0423 0.0225 57018.73174 47.0535 0.0390 0.0523 57022.76169 46.9974 0.0330 0.0288 57026.86587 46.9604 0.0300 0.0346 57043.67305 47.1643 0.0568 −0.0103 57070.67363 47.2080 0.0326 0.0080 57072.63982 47.2065 0.0425 −0.0156 57402.72844 47.0586 0.0499 −0.0392 57432.63093 47.1446 0.0269 0.0052 Bisector errors are twice RV errors
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