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See detailTransiting planets from WASP-South, Euler and TRAPPIST: WASP-68 b, WASP-73 b and WASP-88 b, three hot Jupiters transiting evolved solar-type stars
Delrez, Laetitia ULg; Van Grootel, Valérie ULg; Anderson, D. R. et al

in Astronomy and Astrophysics (2014)

We report the discovery by the WASP transit survey of three new hot Jupiters, WASP-68 b, WASP-73 b and WASP-88 b. WASP-68 b has a mass of 0.95+-0.03 M_Jup, a radius of 1.24-0.06+0.10 R_Jup, and orbits a V ... [more ▼]

We report the discovery by the WASP transit survey of three new hot Jupiters, WASP-68 b, WASP-73 b and WASP-88 b. WASP-68 b has a mass of 0.95+-0.03 M_Jup, a radius of 1.24-0.06+0.10 R_Jup, and orbits a V=10.7 G0-type star (1.24+-0.03 M_sun, 1.69-0.06+0.11 R_sun, T_eff=5911+-60 K) with a period of 5.084298+-0.000015 days. Its size is typical of hot Jupiters with similar masses. WASP-73 b is significantly more massive (1.88-0.06+0.07 M_Jup) and slightly larger (1.16-0.08+0.12 R_Jup) than Jupiter. It orbits a V=10.5 F9-type star (1.34-0.04+0.05 M_sun, 2.07-0.08+0.19 R_sun, T_eff=6036+-120 K) every 4.08722+-0.00022 days. Despite its high irradiation (2.3 10^9 erg s^-1 cm^-2), WASP-73 b has a high mean density (1.20-0.30+0.26 \rho_Jup) that suggests an enrichment of the planet in heavy elements. WASP-88 b is a 0.56+-0.08 M_Jup planet orbiting a V=11.4 F6-type star (1.45+-0.05 M_sun, 2.08-0.06+0.12 R_sun, T_eff=6431+-130 K) with a period of 4.954000+-0.000019 days. With a radius of 1.70-0.07+0.13 R_Jup, it joins the handful of planets with super-inflated radii. The ranges of ages we determine through stellar evolution modeling are 4.5-7.0 Gyr for WASP-68, 2.8-5.7 Gyr for WASP-73 and 1.8-4.3 Gyr for WASP-88. WASP-73 appears to be a significantly evolved star, close to or already in the subgiant phase. WASP-68 and WASP-88 are less evolved, although in an advanced stage of core H-burning. [less ▲]

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See detailWASP-20b and WASP-28b: a hot Saturn and a hot Jupiter in near-aligned orbits around solar-type stars
Anderson, D. R.; Collier Cameron, A.; Hellier, C. et al

E-print/Working paper (2014)

We report the discovery of the planets WASP-20b and WASP-28b along with measurements of their sky-projected orbital obliquities. WASP-20b is an inflated, Saturn-mass planet (0.31 $M_{\rm Jup}$; 1.46 $R ... [more ▼]

We report the discovery of the planets WASP-20b and WASP-28b along with measurements of their sky-projected orbital obliquities. WASP-20b is an inflated, Saturn-mass planet (0.31 $M_{\rm Jup}$; 1.46 $R_{\rm Jup}$) in a 4.9-day, near-aligned ($\lambda = 8.1 \pm 3.6^\circ$) orbit around CD-24 102 ($V$=10.7; F9). WASP-28b is an inflated, Jupiter-mass planet (0.91 $M_{\rm Jup}$; 1.21 $R_{\rm Jup}$) in a 3.4-day, near-aligned ($\lambda = 8 \pm 18^\circ$) orbit around a $V$=12, F8 star. As intermediate-mass planets in short orbits around aged, cool stars ($7^{+2}_{-1}$ Gyr for WASP-20 and $5^{+3}_{-2}$ Gyr for WASP-28; both with $T_{\rm eff}$ < 6250 K), their orbital alignment is consistent with the hypothesis that close-in giant planets are scattered into eccentric orbits with random alignments, which are then circularised and aligned with their stars' spins via tidal dissipation. [less ▲]

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See detailHigh-frequency A-type pulsators discovered using SuperWASP
Holdsworth, Daniel L.; Smalley, B.; Gillon, Michaël ULg et al

in Monthly Notices of the Royal Astronomical Society (2014)

We present the results of a survey using the WASP archive to search for high-frequency pulsations in F-, A- and B-type stars. Over 1.5 million targets have been searched for pulsations with amplitudes ... [more ▼]

We present the results of a survey using the WASP archive to search for high-frequency pulsations in F-, A- and B-type stars. Over 1.5 million targets have been searched for pulsations with amplitudes greater than 0.5 millimagnitude. We identify over 350 stars which pulsate with periods less than 30 min. Spectroscopic follow-up of selected targets has enabled us to confirm 10 new rapidly oscillating Ap stars, 13 pulsating Am stars and the fastest known δ Scuti star. We also observe stars which show pulsations in both the high-frequency domain and the low-frequency δ Scuti range. This work shows the power of the WASP photometric survey to find variable stars with amplitudes well below the nominal photometric precision per observation. [less ▲]

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See detailWASP-103b: a new planet at the edge of tidal disruption
Gillon, Michaël ULg; Anderson, D. R.; Collier-Cameron, A. et al

in Astronomy and Astrophysics (2014)

We report the discovery of WASP-103b, a new ultra-short-period planet (P=22.2 hr) transiting a 12.1 V-magnitude F8-type main-sequence star (1.22+-0.04 Msun, 1.44-0.03+0.05 Rsun, Teff = 6110+-160 K). WASP ... [more ▼]

We report the discovery of WASP-103b, a new ultra-short-period planet (P=22.2 hr) transiting a 12.1 V-magnitude F8-type main-sequence star (1.22+-0.04 Msun, 1.44-0.03+0.05 Rsun, Teff = 6110+-160 K). WASP-103b is significantly more massive (1.49+-0.09 Mjup) and larger (1.53-0.07+0.05 Rjup) than Jupiter. Its large size and extreme irradiation (around 9 10^9 erg/s/cm^2) make it an exquisite target for a thorough atmospheric characterization with existing facilities. Furthermore, its orbital distance is less than 20% larger than its Roche radius, meaning that it might be significantly distorted by tides and might experience mass loss through Roche-lobe overflow. It thus represents a new key object for understanding the last stage of the tidal evolution of hot Jupiters. [less ▲]

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See detailWASP-71b: a bloated hot Jupiter in an 2.9-day, prograde orbit around an evolved F8 star
Smith, A. M. S.; Anderson, D. R.; Bouchy, F. et al

in Astronomy and Astrophysics (2013), 552

We report the discovery by the WASP transit survey of a highly-irradiated, massive (2.242 +/- 0.080 MJup) planet which transits a bright (V = 10.6), evolved F8 star every 2.9 days. The planet, WASP-71b ... [more ▼]

We report the discovery by the WASP transit survey of a highly-irradiated, massive (2.242 +/- 0.080 MJup) planet which transits a bright (V = 10.6), evolved F8 star every 2.9 days. The planet, WASP-71b, is larger than Jupiter (1.46 +/- 0.13 RJup), but less dense (0.71 +/- 0.16 {\rho}Jup). We also report spectroscopic observations made during transit with the CORALIE spectrograph, which allow us to make a highly-significant detection of the Rossiter-McLaughlin effect. We determine the sky-projected angle between the stellar-spin and planetary-orbit axes to be {\lambda} = 20.1 +/- 9.7 degrees, i.e. the system is 'aligned', according to the widely-used alignment criteria that systems are regarded as misaligned only when {\lambda} is measured to be greater than 10 degrees with 3-{\sigma} confidence. WASP-71, with an effective temperature of 6059 +/- 98 K, therefore fits the previously observed pattern that only stars hotter than 6250 K are host to planets in misaligned orbits. We emphasise, however, that {\lambda} is merely the sky-projected obliquity angle; we are unable to determine whether the stellar-spin and planetary-orbit axes are misaligned along the line-of-sight. With a mass of 1.56 +/- 0.07 Msun, WASP-71 was previously hotter than 6250 K, and therefore might have been significantly misaligned in the past. If so, the planetary orbit has been realigned, presumably through tidal interactions with the cooling star's growing convective zone. [less ▲]

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See detailThree irradiated and bloated hot Jupiters: WASP-76b, WASP-82b & WASP-90b
West, R. G.; Almenara, J.-M.; Anderson, D. R. et al

E-print/Working paper (2013)

We report three new transiting hot-Jupiter planets discovered from the WASP surveys combined with radial velocities from OHP/SOPHIE and Euler/CORALIE and photometry from Euler and TRAPPIST. All three ... [more ▼]

We report three new transiting hot-Jupiter planets discovered from the WASP surveys combined with radial velocities from OHP/SOPHIE and Euler/CORALIE and photometry from Euler and TRAPPIST. All three planets are inflated, with radii 1.7-1.8 Rjup. All orbit hot stars, F5-F7, and all three stars have evolved, post-MS radii (1.7-2.2 Rsun). Thus the three planets, with orbits of 1.8-3.9 d, are among the most irradiated planets known. This reinforces the correlation between inflated planets and stellar irradiation. [less ▲]

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See detailThree sub-Jupiter-mass planets: WASP-69b & WASP-84b transit active K dwarfs and WASP-70Ab transits the evolved primary of a G4+K3 binary
Anderson, D. R.; Collier Cameron, A.; Delrez, Laetitia ULg et al

E-print/Working paper (2013)

We report the discovery of the transiting exoplanets WASP-69b, WASP-70Ab and WASP-84b, each of which orbits a bright star (V~10). WASP-69b is a bloated Saturn-mass planet (0.26 M$_{\rm Jup}$, 1.06 R$_{\rm ... [more ▼]

We report the discovery of the transiting exoplanets WASP-69b, WASP-70Ab and WASP-84b, each of which orbits a bright star (V~10). WASP-69b is a bloated Saturn-mass planet (0.26 M$_{\rm Jup}$, 1.06 R$_{\rm Jup}$) in a 3.868-d period around an active mid-K dwarf. We estimate a stellar age of 1 Gyr from both gyrochronological and age-activity relations, though an alternative gyrochronological relation suggests an age of 3 Gyr. ROSAT detected X-rays at a distance of 60$\pm$27 arcsec from WASP-69. If the star is the source then the planet could be undergoing mass-loss at a rate of ~10$^{12}$ g s$^{-1}$. This is 1-2 orders of magnitude higher than the evaporation rate estimated for HD 209458b and HD 189733b, both of which have exhibited anomalously-large Lyman-{\alpha} absorption during transit. WASP-70Ab is a sub-Jupiter-mass planet (0.59 M$_{\rm Jup}$, 1.16R$_{\rm Jup}$) in a 3.713-d orbit around the primary of a spatially-resolved G4+K3 binary, with a separation of 3.3 arcsec ($\geq$800 AU). We exploit the binary nature of the system to construct a H-R diagram, from which we estimate its age to be 9-10 Gyr. WASP-84b is a sub-Jupiter-mass planet (0.69 M$_{\rm Jup}$, 0.94 R$_{\rm Jup}$) in an 8.523-d orbit around an active early-K dwarf. Of the transiting planets discovered from the ground to date, WASP-84b has the third-longest period. From a combination of gyrochronological and age-activity relations we estimate the age of WASP-84 to be ~1 Gyr. For both the active stars WASP-69 and WASP-84 we find a modulation of the radial velocities with a period similar to the photometrically-determined stellar rotation period. We fit the residuals with a low-order harmonic series and subtract the best fit from the RVs prior to deriving the system parameters. In each case the solution is essentially unchanged, with much less than a 1-{\sigma} change to the planetary mass. We found... [less ▲]

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See detailTowards the first transmission spectrum of a gas giant transiting an M-dwarf
Delrez, Laetitia ULg; Gillon, Michaël ULg; Lendl, M. et al

Poster (2013, July 15)

At the forefront of comparative exoplanetology, the atmospheric characterization of transiting exoplanets is revealing the intimate nature of these new worlds. In this exciting context, we are currently ... [more ▼]

At the forefront of comparative exoplanetology, the atmospheric characterization of transiting exoplanets is revealing the intimate nature of these new worlds. In this exciting context, we are currently conducting a VLT observing campaign on a rare exoplanet specimen, WASP-80b, a gas giant in close orbit around a bright nearby M-dwarf. Even if this planet belongs to the hot-Jupiter population, it is actually more ‘warm’ than ‘hot’ with an estimated equilibrium temperature of only 800K. We present here some preliminary results of this program which consists in monitoring four transits of WASP-80b with the FORS2 instrument in multi-object spectroscopic mode in ESO phase 91. Through this approach, our goal is to precisely measure the transmission spectrum of the planet between 740 and 1070 nm in order to constrain the thermal structure and scacering properties of the planetary atmosphere. Furthermore, we will use the water features located around 950 nm to constrain the water mixing ratio in the atmosphere of this peculiar hot Jupiter. [less ▲]

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See detailDiscovery of WASP-65b and WASP-75b: Two Hot Jupiters Without Highly Inflated Radii
Gómez Maqueo Chew, Y.; Faedi, F.; Pollacco, D. et al

E-print/Working paper (2013)

We report the discovery of two transiting hot Jupiters, WASP-65b (M_pl = 1.55 +/- 0.16 M_J; R_pl = 1.11 +/- 0.06 R_J), and WASP-75b (M_pl = 1.07 +/- 0.05 M_J; R_pl = 1.27 +/- 0.05 R_J). They orbit their ... [more ▼]

We report the discovery of two transiting hot Jupiters, WASP-65b (M_pl = 1.55 +/- 0.16 M_J; R_pl = 1.11 +/- 0.06 R_J), and WASP-75b (M_pl = 1.07 +/- 0.05 M_J; R_pl = 1.27 +/- 0.05 R_J). They orbit their host star every 2.311, and 2.484 days, respectively. The planet host WASP-65 is a G6 star (T_eff = 5600 K, [Fe/H] = -0.07 +/- 0.07, age > 8 Gyr); WASP-75 is an F9 star (T_eff = 6100 K, [Fe/H] = 0.07 +/- 0.09, age of 3 Gyr). WASP-65b is one of the densest known exoplanets in the mass range 0.1 and 2.0 M_J (rho_pl = 1.13 +/- 0.08 rho_J), a mass range where a large fraction of planets are found to be inflated with respect to theoretical planet models. WASP-65b is one of only a handful of planets with masses of around 1.5 M_J, a mass regime surprisingly underrepresented among the currently known hot Jupiters. The radius of Jupiter-mass WASP-75b is slightly inflated (< 10%) as compared to theoretical planet models with no core, and has a density similar to that of Saturn (rho_pl = 0.52 +/- 0.06 rho_J). [less ▲]

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See detailWarm Spitzer Occultation Photometry of WASP-26b at 3.6{\mu}m and 4.5{\mu}m
Mahtani, D. P.; Maxted, P. F. L.; Anderson, D. R. et al

in Monthly Notices of the Royal Astronomical Society (2013), 432(1), 693-701

We present new warm Spitzer occultation photometry of WASP-26 at 3.6{\mu}m and 4.5{\mu}m along with new transit photometry taken in the g,r and i bands. We report the first detection of the occultation of ... [more ▼]

We present new warm Spitzer occultation photometry of WASP-26 at 3.6{\mu}m and 4.5{\mu}m along with new transit photometry taken in the g,r and i bands. We report the first detection of the occultation of WASP-26b, with occultation depths at 3.6{\mu}m and 4.5{\mu}m of 0.00126 +/- 0.00013 and 0.00149 +/- 0.00016 corresponding to brightness temperatures of 1825+/-80K and 1725+/-89K, respectively. We find that the eccentricity of the orbit is consistent with a circular orbit at the 1{\sigma} level with a 3{\sigma} upper limit of e < 0.04. According to the activity-inversion relation of Knutson et al. (2010), WASP-26b is predicted to host a thermal inversion. The brightness temperatures deduced from the eclipse depths are consistent with an isothermal atmosphere, although it is within the uncertainties that the planet may host a weak thermal inversion. The data are equally well fit by atmospheric models with or without a thermal inversion. We find that variation in activity of solar-like stars does not change enough over the time-scales of months or years to change the interpretation of the Knutson et al. (2010) activity-inversion relation, provided that the measured activity level is averaged over several nights. Further data are required to fully constrain the thermal structure of the atmosphere because the planet lies very close to the boundary between atmospheres with and without a thermal inversion. [less ▲]

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See detailThermal emission at 3.6-8 micron from WASP-19b: a hot Jupiter without a stratosphere orbiting an active star
Anderson, D. R.; Smith, A. M. S.; Madhusudhan, N. et al

in Monthly Notices of the Royal Astronomical Society (2013), 430(4), 3422-3431

We report detection of thermal emission from the exoplanet WASP-19b at 3.6, 4.5, 5.8 and 8.0 μm. We used the InfraRed Array Camera on the Spitzer Space Telescope to observe two occultations of WASP-19b by ... [more ▼]

We report detection of thermal emission from the exoplanet WASP-19b at 3.6, 4.5, 5.8 and 8.0 μm. We used the InfraRed Array Camera on the Spitzer Space Telescope to observe two occultations of WASP-19b by its host star. We combine our new detections with previous measurements of WASP-19b's emission at 1.6 and 2.09 μm to construct a spectral energy distribution of the planet's dayside atmosphere. By comparing this with model-atmosphere spectra, we find that the dayside atmosphere of WASP-19b lacks a strong temperature inversion. As WASP-19 is an active star (log R'HK = -4.50 ± 0.03), this finding supports the hypothesis of Knutson, Howard and Isaacson that inversions are suppressed in hot Jupiters orbiting active stars. The available data are unable to differentiate between a carbon-rich and an oxygen-rich atmosphere. [less ▲]

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See detailWASP-64b and WASP-72b: two new transiting highly irradiated giant planets
Gillon, Michaël ULg; Anderson, D. R.; Collier-Cameron, A. et al

in Astronomy and Astrophysics (2013), 552

We report the discovery by the WASP transit survey of two new highly irradiated giant planets. WASP-64 b is slightly more massive (1.271 ± 0.068 MJup) and larger (1.271 ± 0.039 RJup) than Jupiter, and is ... [more ▼]

We report the discovery by the WASP transit survey of two new highly irradiated giant planets. WASP-64 b is slightly more massive (1.271 ± 0.068 MJup) and larger (1.271 ± 0.039 RJup) than Jupiter, and is in very-short (a = 0.02648 ± 0.00024 AU, P = 1.5732918 ± 0.0000015 days) circular orbit around a V = 12.3 G7-type dwarf (1.004 ± 0.028 Msun, 1.058 ± 0.025 Rsun, Teff = 5500 ± 150 K). Its size is typical of hot Jupiters with similar masses. WASP-72 b has also a mass a bit higher than Jupiter's (1.461-0.056+0.059 MJup) and orbits very close (0.03708 ± 0.00050 AU, P = 2.2167421 ± 0.0000081 days) to a bright (V = 9.6) and moderately evolved F7-type star (1.386 ± 0.055 Msun, 1.98 ± 0.24 Rsun, Teff = 6250 ± 100 K). Despite its extreme irradiation (~5.5 × 109 erg s-1 cm-2), WASP-72 b has a moderate size (1.27 ± 0.20 RJup) that could suggest a significant enrichment in heavy elements. Nevertheless, the errors on its physical parameters are still too high to draw any strong inference on its internal structure or its possible peculiarity. [less ▲]

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See detailWASP-54b, WASP-56b and WASP-57b: Three new sub-Jupiter mass planets from SuperWASP
Faedi, F.; Pollacco, D.; Barros, S. C. C. et al

in Astronomy and Astrophysics (2013), 551

We present three newly discovered sub-Jupiter mass planets from the SuperWASP survey: WASP-54b is a heavily bloated planet of mass 0.636+0.025-0.024RJ. It orbits a F9 star, evolving off the main sequence ... [more ▼]

We present three newly discovered sub-Jupiter mass planets from the SuperWASP survey: WASP-54b is a heavily bloated planet of mass 0.636+0.025-0.024RJ. It orbits a F9 star, evolving off the main sequence, every 3.69 days. Our MCMC fit of the system yields a slightly eccentric orbit (e = 0.067+0.033-0.025) for WASP-54b. We investigated further the veracity of our detection of the eccentric orbit for WASP-54b, and we find that it could be real. However, given the brightness of WASP-54 V = 10.42 mag, we encourage observations of a secondary eclipse to draw robust conclusions on both the orbital eccentricity and the thermal structure of the planet. WASP-56b and WASP-57b have masses of 0.571+0.034-0.035MJ and 0.672+0.049-0.046MJ, respectively; and radii of 1.092+0.035-0.033RJ for WASP-56b and 0.916+0.017-0.014RJ for WASP-57b. They orbit main sequence stars of spectral type G6 every 4.67 and 2.84 days, respectively. WASP-56b and WASP-57b show no radius anomaly and a high density possibly implying a large core of heavy elements; possibly as high as ~50 M⊕ in the case of WASP-57b. However,the composition of the deep interior of exoplanets remains still undetermined. Thus, more exoplanet discoveries such as the ones presented in this paper, are needed to understand and constrain giant planets' physical properties. [less ▲]

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See detailWASP-80b: a gas giant transiting a cool dwarf
Triaud, A. H. M. J.; Anderson, D. R.; Collier Cameron, A. et al

in Astronomy and Astrophysics (2013), 551

We report the discovery of a planet transiting the star <ASTROBJ>WASP-80</ASTROBJ> (<ASTROBJ>1SWASP J201240.26-020838.2</ASTROBJ>; <ASTROBJ>2MASS J20124017-0208391</ASTROBJ>; <ASTROBJ>TYC 5165-481-1 ... [more ▼]

We report the discovery of a planet transiting the star <ASTROBJ>WASP-80</ASTROBJ> (<ASTROBJ>1SWASP J201240.26-020838.2</ASTROBJ>; <ASTROBJ>2MASS J20124017-0208391</ASTROBJ>; <ASTROBJ>TYC 5165-481-1</ASTROBJ>; <ASTROBJ>BPM 80815</ASTROBJ>; V = 11.9, K = 8.4). Our analysis shows this is a 0.55 ± 0.04 M[SUB]jup[/SUB], 0.95 ± 0.03 R[SUB]jup[/SUB] gas giant on a circular 3.07 day orbit around a star with a spectral type between K7V and M0V. This system produces one of the largest transit depths so far reported, making it a worthwhile target for transmission spectroscopy. We find a large discrepancy between the vsini[SUB]⋆[/SUB] inferred from stellar line broadening and the observed amplitude of the Rossiter-McLaughlin effect. This can be understood either by an orbital plane nearly perpendicular to the stellar spin or by an additional, unaccounted for source of broadening. Using WASP-South photometric observations, from Sutherland (South Africa), confirmed with the 60 cm TRAPPIST robotic telescope, EulerCam, and the CORALIE spectrograph on the Swiss 1.2 m Euler Telescope, and HARPS on the ESO 3.6 m (Prog ID 089.C-0151), all three located at La Silla Observatory, Chile.Radial velocity and photometric data are available in electronic form at the CDS via anonymous ftp to <A href="http://cdsarc.u-strasbg.fr">cdsarc.u-strasbg.fr</A>(<A href="http://130.79.128.5">130.79.128.5</A>) or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/551/A80">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/551/A80</A> [less ▲]

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See detailAccurate spectroscopic parameters of WASP planet host stars
Doyle, Amanda P.; Smalley, B.; Maxted, P. F. L. et al

in Monthly Notices of the Royal Astronomical Society (2013), 428(4), 3164-3172

We have made a detailed spectral analysis of eleven Wide Angle Search for Planets (WASP) planet host stars using high signal-to-noise (S/N) HARPS spectra. Our line list was carefully selected from the ... [more ▼]

We have made a detailed spectral analysis of eleven Wide Angle Search for Planets (WASP) planet host stars using high signal-to-noise (S/N) HARPS spectra. Our line list was carefully selected from the spectra of the Sun and Procyon, and we made a critical evaluation of the atomic data. The spectral lines were measured using equivalent widths. The procedures were tested on the Sun and Procyon prior to be being used on the WASP stars. The effective temperature, surface gravity, microturbulent velocity and metallicity were determined for all the stars. We show that abundances derived from high S/N spectra are likely to be higher than those obtained from low S/N spectra, as noise can cause the equivalent width to be underestimated. We also show that there is a limit to the accuracy of stellar parameters that can be achieved, despite using high S/N spectra, and the average uncertainty in effective temperature, surface gravity, microturbulent velocity and metallicity is 83 K, 0.11 dex, 0.11 km/s and 0.10 dex respectively. [less ▲]

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See detailWASP-77 Ab: A Transiting Hot Jupiter Planet in a Wide Binary System
Maxted, P. F. L.; Anderson, D. R.; Collier Cameron, A. et al

in Publications of the Astronomical Society of the Pacific (2013), 125

We report the discovery of a transiting planet with an orbital period of 1.36 days orbiting the brighter component of the visual binary star BD 07 436. The host star, WASP-77 A, is a moderately bright G8 ... [more ▼]

We report the discovery of a transiting planet with an orbital period of 1.36 days orbiting the brighter component of the visual binary star BD 07 436. The host star, WASP-77 A, is a moderately bright G8 V star (V=10.3) with a metallicity close to solar ([Fe/H] = 0.0 ± 0.1). The companion star, WASP-77 B, is a K-dwarf approximately 2 mag fainter at a separation of approximately 3″. The spectrum of WASP-77 A shows emission in the cores of the Caii H and K lines, indicative of moderate chromospheric activity. The Wide Angle Search for Planets (WASP) light curves show photometric variability with a period of 15.3 days and an amplitude of about 0.3% that is probably due to the magnetic activity of the host star. We use an analysis of the combined photometric and spectroscopic data to derive the mass and radius of the planet (1.76 ± 0.06 M[SUB]Jup[/SUB], 1.21 ± 0.02 R[SUB]Jup[/SUB]). The age of WASP-77 A estimated from its rotation rate (˜1 Gyr) agrees with the age estimated in a similar way for WASP-77 B (˜0.6 Gyr) but is in poor agreement with the age inferred by comparing its effective temperature and density to stellar models (˜8 Gyr). Follow-up observations of WASP-77 Ab will make a useful contribution to our understanding of the influence of binarity and host star activity on the properties of hot Jupiters. [less ▲]

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See detailAnalysis of Spin-Orbit Alignment in the WASP-32, WASP-38, and HAT-P-27/WASP-40 Systems
Brown, D. J. A.; Collier Cameron, A.; Díaz, R. F. et al

in Astrophysical Journal (2012), 760

We present measurements of the spin-orbit alignment angle, λ, for the hot Jupiter systems WASP-32, WASP-38, and HAT-P-27/WASP-40, based on data obtained using the HARPS spectrograph. We analyze the ... [more ▼]

We present measurements of the spin-orbit alignment angle, λ, for the hot Jupiter systems WASP-32, WASP-38, and HAT-P-27/WASP-40, based on data obtained using the HARPS spectrograph. We analyze the Rossiter-McLaughlin effect for all three systems and also carry out Doppler tomography for WASP-32 and WASP-38. We find that WASP-32 (T [SUB]eff[/SUB] = 6140[SUP]+90[/SUP] [SUB]- 100[/SUB] K) is aligned, with an alignment angle of λ = 10fdg5[SUP] + 6.4[/SUP] [SUB] - 6.5[/SUB] obtained through tomography, and that WASP-38 (T [SUB]eff[/SUB] = 6180[SUP]+40[/SUP] [SUB]- 60[/SUB] K) is also aligned, with tomographic analysis yielding λ = 7fdg5[SUP] + 4.7[/SUP] [SUB] - 6.1[/SUB]. The latter result provides an order-of-magnitude improvement in the uncertainty in λ compared to the previous analysis of Simpson et al. We are only able to loosely constrain the angle for HAT-P-27/WASP-40 (T [SUB]eff[/SUB] = 5190[SUP]+160[/SUP] [SUB]- 170[/SUB] K) to λ = 24fdg2[SUP] + 76.0[/SUP] [SUB] - 44.5[/SUB], owing to the poor signal-to-noise ratio of our data. We consider this result a non-detection under a slightly updated version of the alignment test of Brown et al. We place our results in the context of the full sample of spin-orbit alignment measurements, finding that they provide further support for previously established trends. Based on observations (under proposal 087.C-0649) made using the HARPS High Resolution Échelle Spectrograph mounted on the ESO 3.6 m at the ESO La Silla observatory. [less ▲]

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See detailWASP-36b: A new transiting planet around a metal-poor G-dwarf, and an analysis of correlated noise in transit light curves
Smith, A. M. S.; Anderson, D. R.; Collier Cameron, A. et al

in Astronomical Journal (The) (2012), 143(4), 10

We report the discovery, from WASP and CORALIE, of a transiting exoplanet in a 1.54-d orbit. The host star, WASP-36, is a magnitude 12.7, metal-poor G2 dwarf (Teff = 5881 +/- 137 K), with [Fe/H] = -0.31 ... [more ▼]

We report the discovery, from WASP and CORALIE, of a transiting exoplanet in a 1.54-d orbit. The host star, WASP-36, is a magnitude 12.7, metal-poor G2 dwarf (Teff = 5881 +/- 137 K), with [Fe/H] = -0.31 +/- 0.12. We determine the planet to have mass and radius respectively 2.27 +/- 0.07 and 1.27 +/- 0.03 times that of Jupiter. We have eight partial or complete transit light curves, from four different observatories, which allows us to investigate the extent to which red noise in follow-up light curves affects the fitted system parameters. We find that the solutions obtained by analysing each of these light curves independently are consistent with our global fit to all the data, despite the apparent presence of correlated noise in at least two of the light curves. [less ▲]

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See detailWASP-42 b and WASP-49 b: two new transiting sub-Jupiters
Lendl, M; Anderson, D R; Collier-Cameron, A et al

in Astronomy and Astrophysics (2012), 544

We report the discovery of two new transiting planets from the WASP survey. WASP-42 b is a 0.500 +- 0.035 M_J planet orbiting a K1 star at a separation of 0.0548 +- 0.0017 AU with a period of 4.9816872 ... [more ▼]

We report the discovery of two new transiting planets from the WASP survey. WASP-42 b is a 0.500 +- 0.035 M_J planet orbiting a K1 star at a separation of 0.0548 +- 0.0017 AU with a period of 4.9816872 +- 0.0000073 days. The radius of WASP-42 is 1.080 +- 0.057 R_J while its equilibrium temperature is T_eq = 995 +- 34 K. We detect some evidence of a small but non-zero eccentricity of e = 0.060 +- 0.013. WASP-49 b is a 0.378 +- 0.027 M_J planet around an old G6 star. It has a period of 2.7817387 +- 5.6 x 10-6 days and a separation of 0.0379 +- 0.0011 AU. This planet is slightly bloated, having a radius of 1.115 +- 0.056 R_J and an equilibrium temperature of T_eq = 1369 +- 42 K. Both planets have been followed up intensively in photometry, in total we have obtained 5 full and one partial transit light curves of WASP-42 and 4 full and one partial light curves of WASP-49 using the Euler-Swiss, TRAPPIST and Faulkes South telescopes. [less ▲]

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See detailThe TRAPPIST survey of southern transiting planets. I. Thirty eclipses of the ultra-short period planet WASP-43 b
Gillon, Michaël ULg; Triaud, A H M J; Fortney, J. J. et al

in Astronomy and Astrophysics (2012), 542

We present twenty-three transit light curves and seven occultation light curves for the ultra-short period planet WASP-43 b, in addition to eight new measurements of the radial velocity of the star ... [more ▼]

We present twenty-three transit light curves and seven occultation light curves for the ultra-short period planet WASP-43 b, in addition to eight new measurements of the radial velocity of the star. Thanks to this extensive data set, we improve significantly the parameters of the system. Notably, the largely improved precision on the stellar density (2.41 ± 0.08 ρsun) combined with constraining the age to be younger than a Hubble time allows us to break the degeneracy of the stellar solution mentioned in the discovery paper. The resulting stellar mass and size are 0.717 ± 0.025 Msun and 0.667 ± 0.011 Rsun. Our deduced physical parameters for the planet are 2.034 ± 0.052 MJup and 1.036 ± 0.019 RJup. Taking into account its level of irradiation, the high density of the planet favors an old age and a massive core. Our deduced orbital eccentricity, 0.0035-0.0025+0.0060, is consistent with a fully circularized orbit. We detect the emission of the planet at 2.09 μm at better than 11-σ, the deduced occultation depth being 1560 ± 140 ppm. Our detection of the occultation at 1.19 μm is marginal (790 ± 320 ppm) and more observations are needed to confirm it. We place a 3-σ upper limit of 850 ppm on the depth of the occultation at ~0.9 μm. Together, these results strongly favor a poor redistribution of the heat to the night-side of the planet, and marginally favor a model with no day-side temperature inversion. [less ▲]

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