We report on the discovery of WASP-12b, a new transiting extrasolar planet with R pl = 1.79 +0.09 −0.09 R J 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.

We present near-UV transmission spectroscopy of the highly irradiated transiting exoplanet WASP-12b, obtained with the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST). The spectra cover three distinct wavelength ranges:NUVA (2539-2580 Å); NUVB (2655-2696 Å); and NUVC (2770-2811 Å). 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 2.5σ level. We detect extra absorption in the Mg II λλ2800 resonance line cores at the 2.8σ 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 ionised 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 exhibits an early ingress, contrary to model expectations; we speculate this could be due to the presence of a disk of previously stripped material. Subject headings: stars: individual (WASP-12) 1 http://archive.stsci.edu/ 2 See the COS Data Handbook for more information on CALCOS:

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 Teff= 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+0.08−0.14MJ and radius 1.31+0.07−0.14RJ 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.

The WASP (wide angle search for planets) project is an exoplanet transit survey that has been automatically taking wide field images since 2004. Two instruments, one in La Palma and the other in South Africa, continually monitor the night sky, building up light curves of millions of unique objects. These light curves are used to search for the characteristics of exoplanetary transits. This first public data release (DR1) of the WASP archive makes available all the light curve data and images from 2004 up to 2008 in both the Northern and Southern hemispheres. A web interface (www.wasp.le.ac.uk/public/) to the data allows easy access over the Internet. The data set contains 3 631 972 raw images and 17 970 937 light curves. In total the light curves have 119 930 299 362 data points available between them.

We present nine newly observed transits of TrES-3, taken as part of a transit timing program using the RISE instrument on the Liverpool Telescope. A Markov-Chain Monte-Carlo analysis was used to determine the planet-star radius ratio and inclination of the system, which were found to be R p /R ⋆ = 0.1664 +0.0011 −0.0018 and i = 81.73 +0.13 −0.04 respectively, consistent with previous results. The central transit times and uncertainties were also calculated, using a residual-permutation algorithm as an independent check on the errors. A re-analysis of eight previously published TrES-3 light curves was conducted to determine the transit times

Some of the first results are reported from RISE -a new fast camera mounted on the Liverpool Telescope primarily designed to obtain high time-resolution light curves of transiting extrasolar planets for the purpose of transit timing. A full and partial transit of WASP-3 are presented, and a Markov-Chain Monte Carlo analysis is used to update the parameters from the discovery paper. This results in a planetary radius of 1.29−0.12 R J and therefore a density of 0.82 +0.14 −0.09 ρ J , consistent with previous results. The inclination is 85.06 +0.16−0.15 deg, in agreement (but with a significant improvement in the precision) with the previously determined value. Central transit times are found to be consistent with the ephemeris given in the discovery paper; however, a new ephemeris calculated using the longer baseline results in T c (0) = 2 454 605.55915 ± 0.00023 HJD and P = 1.846835 ± 0.000002 days.

We report the discovery of WASP-4b, a large transiting gas-giant planet with an orbital period of 1.34 days. This is the first planet to be discovered by the SuperWASP-South observatory and CORALIE collaboration and the first planet orbiting a star brighter than 16 th magnitude to be discovered in the Southern hemisphere. A simultaneous fit to high-quality lightcurves and precision radial-velocity measurements leads to a planetary mass of 1.22 +0.09 −0.08 M Jup and a planetary radius of 1.42 +0.07 −0.04 R Jup . The host star is USNO-B1.0 0479-0948995, a G7V star of visual magnitude 12.5. As a result of the short orbital period, the predicted surface temperature of the planet is 1761 K, making it an ideal candidate for detections of the secondary eclipse at infrared wavelengths.

We report the discovery of WASP‐10b, a new transiting extrasolar planet (ESP) discovered by the Wide Angle Search for Planets (WASP) Consortium and confirmed using Nordic Optical Telescope FIbre‐fed Echelle Spectrograph and SOPHIE radial velocity data. A 3.09‐d period, 29 mmag transit depth and 2.36 h duration are derived for WASP‐10b using WASP and high‐precision photometric observations. Simultaneous fitting to the photometric and radial velocity data using a Markov Chain Monte Carlo procedure leads to a planet radius of 1.28RJ, a mass of 2.96MJ and eccentricity of ≈0.06. WASP‐10b is one of the more massive transiting ESPs, and we compare its characteristics to the current sample of transiting ESP, where there is currently little information for masses greater than ≈2MJ and non‐zero eccentricities. WASP‐10's host star, GSC 2752−00114 (USNO‐B1.0 1214−0586164) is among the fainter stars in the WASP sample, with V= 12.7 and a spectral type of K5. This result shows promise for future late‐type dwarf star surveys.