The Rossiter-McLaughlin effect observed for transiting exoplanets often requires prior knowledge of the stellar projected equatorial rotational velocity (v sin i). This is usually provided by measuring the broadening of spectral lines, however this method has uncertainties as lines are also broadened by velocity fields in the stellar photosphere known as macroturbulence (v mac ). We have estimated accurate v sin i values from asteroseismic analyses of main sequence stars observed by Kepler. The rotational frequency splittings of the detected solar-like oscillations of these stars are determined largely by the near-surface rotation. These estimates have been used to infer the v mac values for 28 Kepler stars. Out of this sample, 26 stars were used along with the Sun to obtain a new calibration between v mac , effective temperature and surface gravity. The new calibration is valid for the temperature range 5200 to 6400 K and the gravity range 4.0 to 4.6 dex. A comparison is also provided with previous v mac calibrations. As a result of this work, v mac , and thus v sin i, can now be determined with confidence for stars that do not have asteroseismic data available. We present new spectroscopic v sin i values for the WASP planet host stars, using high resolution HARPS spectra.

We present the discovery of four new transiting hot Jupiters, detected mainly from SuperWASP-North and SOPHIE observations. These new planets, WASP-52b, WASP-58b, WASP-59b, and WASP-60b, have orbital periods ranging from 1.7 to 7.9 days, masses between 0.46 and 0.94 M Jup , and radii between 0.73 and 1.49 R Jup . Their G1 to K5 dwarf host stars have V magnitudes in the range 11.7−13.0. The depths of the transits are between 0.6 and 2.7%, depending on the target. With their large radii, WASP-52b and WASP-58b are new cases of low-density, inflated planets, whereas WASP-59b is likely to have a large, dense core. WASP-60 shows shallow transits. In the case of WASP-52 we also detected the Rossiter-McLaughlin anomaly via time-resolved spectroscopy of a transit. We measured the sky-projected obliquity λ = 24 • +17 −9 , indicating that WASP-52b orbits in the same direction as its host star is rotating and that this prograde orbit is slightly misaligned with the stellar equator. These four new planetary systems increase our statistics on hot Jupiters and provide new targets for follow-up studies.

We report the discovery of a planet transiting the star WASP-80 (1SWASP J201240.26-020838.2; 2MASS J20124017-0208391; TYC 5165-481-1; BPM 80815; V = 11.9, K = 8.4). Our analysis shows this is a 0.55 ± 0.04 M jup , 0.95 ± 0.03 R jup 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 v sin i 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.

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 (T eff ), surface gravity (log g), microturbulent velocity (v mic ) 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 T eff , log g, v mic and metallicity is 83 K, 0.11 dex, 0.11 km s −1 and 0.10 dex respectively.

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 ± 7.3 × 10 −6 days. The radius of WASP-42 b is 1.080 ± 0.057 R J while its equilibrium temperature is T eq = 995 ± 34 K. We detect some evidence for 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 × 10 −6 days and a separation of 0.0379 ± 0.0011 AU. This planet is slightly bloated, having a radius of 1.115 ± 0.047 R J and an equilibrium temperature of T eq = 1369 ± 39 K. Both planets have been followed up photometrically, and 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.