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Publications of the Astronomical Society of the Pacific | 2006

The WASP Project and the SuperWASP Cameras

Don Pollacco; I. Skillen; A. Collier Cameron; D. J. Christian; C. Hellier; J. Irwin; T. A. Lister; R. A. Street; Richard G. West; D. R. Anderson; W. I. Clarkson; H. J. Deeg; B. Enoch; A. Evans; A. Fitzsimmons; C. A. Haswell; Simon T. Hodgkin; K. Horne; Stephen R. Kane; F. P. Keenan; P. F. L. Maxted; A. J. Norton; Julian P. Osborne; N. Parley; R. Ryans; B. Smalley; P. J. Wheatley; D. M. Wilson

ABSTRACT The SuperWASP cameras are wide‐field imaging systems at the Observatorio del Roque de los Muchachos on the island of La Palma in the Canary Islands, and at the Sutherland Station of the South African Astronomical Observatory. Each instrument has a field of view of some 482 deg2 with an angular scale of 13 \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape


The Astrophysical Journal | 2009

WASP-12b: The Hottest Transiting Extrasolar Planet Yet Discovered

L. Hebb; Andrew Collier-Cameron; B. Loeillet; Don Pollacco; G. Hébrard; R. A. Street; F. Bouchy; H. C. Stempels; C. Moutou; E. K. Simpson; S. Udry; Y. C. Joshi; Richard G. West; I. Skillen; D. M. Wilson; I. McDonald; N. P. Gibson; S. Aigrain; D. R. Anderson; Chris R. Benn; D. J. Christian; B. Enoch; C. A. Haswell; C. Hellier; K. Horne; J. Irwin; T. A. Lister; P. F. L. Maxted; Michel Mayor; A. J. Norton

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Nature | 2011

A high C/O ratio and weak thermal inversion in the atmosphere of exoplanet WASP-12b

Nikku Madhusudhan; Joseph E. Harrington; Kevin B. Stevenson; Sarah Nymeyer; Christopher J. Campo; P. J. Wheatley; Drake Deming; Jasmina Blecic; Ryan A. Hardy; Nate B. Lust; D. R. Anderson; Andrew Collier-Cameron; Christopher B. T. Britt; William C. Bowman; L. Hebb; C. Hellier; P. F. L. Maxted; Don Pollacco; Richard G. West

\end{document} 7 pixel−1, and is capable of delivering photometry with accuracy better than 1% for objects having \documentclass{aastex} \usepackage{amsbsy} \usepa...


Monthly Notices of the Royal Astronomical Society | 2007

WASP-1b and WASP-2b: two new transiting exoplanets detected with SuperWASP and SOPHIE

A. Collier Cameron; F. Bouchy; G. Hébrard; P. F. L. Maxted; Don Pollacco; Frederic Pont; I. Skillen; B. Smalley; R. A. Street; Richard G. West; D. M. Wilson; Suzanne Aigrain; D. J. Christian; W. I. Clarkson; B. Enoch; A. Evans; A. Fitzsimmons; M. Fleenor; Michaël Gillon; C. A. Haswell; L. Hebb; C. Hellier; Simon T. Hodgkin; K. Horne; J. Irwin; S. R. Kane; F. P. Keenan; B. Loeillet; Tim Lister; Michel Mayor

We report on the discovery of WASP-12b, a new transiting extrasolar planet with R pl = 1.79+0.09 –0.09 RJ and M pl = 1.41+0.10 –0.10 M J. The planet and host star properties were derived from a Monte Carlo Markov Chain analysis of the transit photometry and radial velocity data. Furthermore, by comparing the stellar spectrum with theoretical spectra and stellar evolution models, we determined that the host star is a supersolar metallicity ([M/H] = 0.3+0.05 –0.15), late-F (T eff = 6300+200 –100 K) star which is evolving off the zero-age main sequence. The planet has an equilibrium temperature of T eq = 2516 K caused by its very short period orbit (P = 1.09 days) around the hot, twelfth magnitude host star. WASP-12b has the largest radius of any transiting planet yet detected. It is also the most heavily irradiated and the shortest period planet in the literature.


The Astrophysical Journal | 2010

Metals in the Exosphere of the Highly Irradiated Planet WASP-12b

L. Fossati; C. A. Haswell; Cynthia S. Froning; L. Hebb; S. Holmes; U. Kolb; Ch. Helling; A. Carter; P. J. Wheatley; Andrew Collier Cameron; B. Loeillet; Don Pollacco; R. A. Street; H. C. Stempels; E. K. Simpson; S. Udry; Y. C. Joshi; Richard G. West; I. Skillen; D. M. Wilson

The carbon-to-oxygen ratio (C/O) in a planet provides critical information about its primordial origins and subsequent evolution. A primordial C/O greater than 0.8 causes a carbide-dominated interior, as opposed to the silicate-dominated composition found on Earth; the atmosphere can also differ from those in the Solar System. The solar C/O is 0.54 (ref. 3). Here we report an analysis of dayside multi-wavelength photometry of the transiting hot-Jupiter WASP-12b (ref. 6) that reveals C/O ≥ 1 in its atmosphere. The atmosphere is abundant in CO. It is depleted in water vapour and enhanced in methane, each by more than two orders of magnitude compared to a solar-abundance chemical-equilibrium model at the expected temperatures. We also find that the extremely irradiated atmosphere (T > 2,500 K) of WASP-12b lacks a prominent thermal inversion (or stratosphere) and has very efficient day–night energy circulation. The absence of a strong thermal inversion is in stark contrast to theoretical predictions for the most highly irradiated hot-Jupiter atmospheres.


Monthly Notices of the Royal Astronomical Society | 2008

WASP-3b: a strongly irradiated transiting gas-giant planet

Don Pollacco; I. Skillen; A. Collier Cameron; B. Loeillet; H. C. Stempels; F. Bouchy; N. P. Gibson; L. Hebb; G. Hébrard; Y. C. Joshi; I. McDonald; B. Smalley; A. M. S. Smith; R. A. Street; S. Udry; Richard G. West; D. M. Wilson; P. J. Wheatley; Suzanne Aigrain; K. Alsubai; Chris R. Benn; V. A. Bruce; D. J. Christian; W. I. Clarkson; B. Enoch; A. Evans; A. Fitzsimmons; C. A. Haswell; C. Hellier; Samantha Hickey

We have detected low-amplitude radial-velocity variations in two stars, USNO-B1.0 1219‐ 0005465 (GSC 02265‐00107 = WASP‐1) and USNO-B1.0 0964‐0543604 (GSC 00522‐ 01199 = WASP‐2). Both stars were identified as being likely host stars of transiting exoplanets in the 2004 SuperWASP wide-field transit survey. Using the newly commissioned radial-velocity spectrograph SOPHIE at the Observatoire de Haute-Provence, we found that both objects exhibit reflex orbital radial-velocity variations with amplitudes characteristic of planetary-mass companions and in-phase with the photometric orbits. Line-bisector studies rule out faint blended binaries as the cause of either the radial-velocity variations or the transits. We perform preliminary spectral analyses of the host stars, which together with their radialvelocity variations and fits to the transit light curves yield estimates of the planetary masses and radii. WASP-1b and WASP-2b have orbital periods of 2.52 and 2.15 d, respectively. Given mass estimates for their F7V and K1V primaries, we derive planet masses 0.80‐0.98 and 0.81‐ 0.95 times that of Jupiter, respectively. WASP-1b appears to have an inflated radius of at least 1.33 RJup, whereas WASP-2b has a radius in the range 0.65‐1.26 RJup.


Scopus | 2009

WASP-12b: The hottest transiting extrasolar planet yet discovered

L. Hebb; Andrew Collier-Cameron; H. C. Stempels; B. Enoch; K. Horne; N. Parley; B. Loeillet; C. Moutou; Don Pollacco; E. K. Simpson; Y. C. Joshi; N. P. Gibson; D. J. Christian; G. Hébrard; Francois Bouchy; R. A. Street; T. A. Lister; S. Udry; M. Mayor; D. Queloz; Richard G. West; I. Skillen; Chris R. Benn; D. M. Wilson; I. McDonald; Anderson; C. Hellier; P. F. L. Maxted; B. Smalley; S. Aigrain

We present near-UV transmission spectroscopy of the highly irradiated transiting exoplanet WASP-12b, obtained with the Cosmic Origins Spectrograph on the Hubble Space Telescope. The spectra cover three distinct wavelength ranges: NUVA (2539-2580 angstrom), NUVB (2655-2696 angstrom), and NUVC (2770-2811 angstrom). Three independent methods all reveal enhanced transit depths attributable to absorption by resonance lines of metals in the exosphere of WASP-12b. Light curves of total counts in the NUVA and NUVC wavelength ranges show a detection at a 2.5 sigma level. We detect extra absorption in the Mg II lambda lambda 2800 resonance line cores at the 2.8 sigma level. The NUVA, NUVB, and NUVC light curves imply effective radii of 2.69 +/- 0.24 R-J, 2.18 +/- 0.18 R-J, and 2.66 +/- 0.22 R-J respectively, suggesting the planet is surrounded by an absorbing cloud which overfills the Roche lobe. We detect enhanced transit depths at the wavelengths of resonance lines of neutral sodium, tin, and manganese, and at singly ionized ytterbium, scandium, manganese, aluminum, vanadium, and magnesium. We also find the statistically expected number of anomalous transit depths at wavelengths not associated with any known resonance line. Our data are limited by photon noise, but taken as a whole the results are strong evidence for an extended absorbing exosphere surrounding the planet. The NUVA data exhibit an early ingress, contrary to model expectations; we speculate this could be due to the presence of a disk of previously stripped material.


The Astrophysical Journal | 2010

WASP-17b: AN ULTRA-LOW DENSITY PLANET IN A PROBABLE RETROGRADE ORBIT*

D. R. Anderson; C. Hellier; M. Gillon; A. H. M. J. Triaud; B. Smalley; L. Hebb; A. Collier Cameron; P. F. L. Maxted; D. Queloz; Richard G. West; S. J. Bentley; B. Enoch; K. Horne; T. A. Lister; M. Mayor; N. Parley; F. Pepe; Don Pollacco; D. Ségransan; S. Udry; D. M. Wilson

We report the discovery of WASP-3b, the third transiting exoplanet to be discovered by the WASP and SOPHIE collaboration. WASP-3b transits its host star USNO-B1.0 1256−0285133 every 1.846 834 ± 0.000 002 d. Our high-precision radial velocity measurements present a variation with amplitude characteristic of a planetary-mass companion and in phase with the light curve. Adaptive optics imaging shows no evidence for nearby stellar companions, and line-bisector analysis excludes faint, unresolved binarity and stellar activity as the cause of the radial velocity variations. We make a preliminary spectroscopic analysis of the host star and find it to have T eff = 6400 ± 100 K and log g = 4.25 ± 0.05 which suggests it is most likely an unevolved main-sequence star of spectral type F7-8V. Our simultaneous modelling of the transit photometry and reflex motion of the host leads us to derive a mass of 1.76 +0.08 −0.14 MJ and radius 1.31 +0.07 −0.14 RJ for WASP-3b. The proximity and relative temperature of the host star suggests that WASP-3b is one of the hottest exoplanets known, and thus has the potential to place stringent constraints on exoplanet atmospheric models.


Monthly Notices of the Royal Astronomical Society | 2010

Line-profile tomography of exoplanet transits – II. A gas-giant planet transiting a rapidly rotating A5 star★

A. Collier Cameron; E. W. Guenther; B. Smalley; I. McDonald; L. Hebb; Johannes Andersen; Th. Augusteijn; S. C. C. Barros; D. J. A. Brown; William D. Cochran; Michael Endl; Stephen J. Fossey; M. Hartmann; P. F. L. Maxted; Don Pollacco; I. Skillen; J. H. Telting; Ingo P. Waldmann; Richard G. West

We report on the discovery of WASP-12b, a new transiting extrasolar planet with R pl = 1.79+0.09 –0.09 RJ and M pl = 1.41+0.10 –0.10 M J. The planet and host star properties were derived from a Monte Carlo Markov Chain analysis of the transit photometry and radial velocity data. Furthermore, by comparing the stellar spectrum with theoretical spectra and stellar evolution models, we determined that the host star is a supersolar metallicity ([M/H] = 0.3+0.05 –0.15), late-F (T eff = 6300+200 –100 K) star which is evolving off the zero-age main sequence. The planet has an equilibrium temperature of T eq = 2516 K caused by its very short period orbit (P = 1.09 days) around the hot, twelfth magnitude host star. WASP-12b has the largest radius of any transiting planet yet detected. It is also the most heavily irradiated and the shortest period planet in the literature.


Scopus | 2010

Line-profile tomography of exoplanet transits - II. A gas-giant planet transiting a rapidly rotating A5 star

Ac. Cameron; D. J. A. Brown; E. W. Guenther; M. Hartmann; B. Smalley; I. McDonald; P. F. L. Maxted; L. Hebb; Johannes Andersen; T. Augusteijn; J. H. Telting; S. C. C. Barros; Don Pollacco; William D. Cochran; Michael Endl; S. J. Fossey; Ingo P. Waldmann; I. Skillen; Richard G. West

We report the discovery of the transiting giant planet WASP-17b, the least-dense planet currently known. It is 1.6 Saturn masses, but 1.5-2 Jupiter radii, giving a density of 6%-14% that of Jupiter. WASP-17b is in a 3.7 day orbit around a sub-solar metallicity, V = 11.6, F6 star. Preliminary detection of the Rossiter-McLaughlin effect suggests that WASP-17b is in a retrograde orbit (λ –150°), indicative of a violent history involving planet-planet or star-planet scattering. WASP-17bs bloated radius could be due to tidal heating resulting from recent or ongoing tidal circularization of an eccentric orbit, such as the highly eccentric orbits that typically result from scattering interactions. It will thus be important to determine more precisely the current orbital eccentricity by further high-precision radial velocity measurements or by timing the secondary eclipse, both to reduce the uncertainty on the planets radius and to test tidal-heating models. Owing to its low surface gravity, WASP-17bs atmosphere has the largest scale height of any known planet, making it a good target for transmission spectroscopy.

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S. Udry

University of Geneva

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F. Pepe

University of Geneva

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