Orbital eccentricity of WASP-12 and WASP-14 from new radial velocity monitoring with SOPHIE★

Abstract

As part of the long‐term radial velocity monitoring of known transiting planets, we have acquired new radial velocity data for the two transiting systems WASP‐12 and WASP‐14, each harbouring a gas giant on a close orbit (orbital period of 1.09 and 2.24 d, respectively). In both cases, the initial orbital solution suggested a significant orbital eccentricity, 0.049 ± 0.015 for WASP‐12b and 0.091 ± 0.003 for WASP‐14b. Since then, measurements of the occultation of WASP‐12 in the infrared have indicated that one projection of the eccentricity (e cos ω) was close to zero, casting doubt on the eccentricity from the initial radial velocity orbit. Our measurements show that the radial velocity data are compatible with a circular orbit. A MCMC analysis taking into account the presence of correlated systematic noise in both the radial velocity and photometric data gives e= 0.017+0.015−0.010. In contrast, we confirm the orbital eccentricity of WASP‐14b, and refine its value to e= 0.0877 ± 0.0030, a 10σ detection. WASP‐14b is thus the closest presently known planet with a confirmed eccentric orbit.

Ground-based near-UV observations of 15 transiting exoplanets: constraints on their atmospheres and no evidence for asymmetrical transits

“…There have been extensive photometric and spectroscopic studies of WASP-12b (López-Morales et al 2010;Campo et al 2011;Chan et al 2011;Croll et al 2011;Husnoo et al 2011;Maciejewski et al 2011Maciejewski et al , 2013Madhusudhan et al 2011;Cowan et al 2012;Crossfield, Hansen & Barman 2012;Haswell et al 2012;Sada et al 2012;Sokov et al 2012;Southworth et al 2012b;Zhao et al 2012;Copperwheat et al 2013;Crossfield et al 2013;Föhring et al 2013;Fossati et al 2013;Mandell et al 2013;Sing et al 2013;Swain et al 2013;Bechter et al 2014 Table 14. Physical properties of WASP-12b, WASP-33b, WASP-36b, WASP-44b, WASP-48b, and WASP-77Ab derived from the light-curve modelling.…”

Multi-site campaign for transit timing variations of WASP-12 b: possible detection of a long-period signal of planetary origin

“…We used data from Hebb et al (2009), Husnoo et al (2011, and Albrecht et al (2012). The datapoints in transit phase (±1.6 h from predicted mid-transit times) were removed to avoid interference from the Rossiter-McLaughlin (RM) effect (Rossiter 1924;McLaughlin 1924), which manifests itself as a distortion of the spectral lines of the host star during transit.…”

The follow-up observations for the transit events of WASP-12b

“…Table 1 lists the part results. The period of 1.091412 days is different from above one, but is close to the value of Husnoo et al (2011).…”

“…1 shows 4 transit light curves and the model data calculated with the bestfitting parameters. Secondly, the observed light curves combined with the radial velocity data of Hebb et al (2009) and Husnoo et al (2011) are analyzed together with MCMC procedure. Table 1 lists the part results.…”

“…The apparent eccentricity is identified by some authors (Hebb et al 2009;Campo et al 2011;Lopez-Morales et al 2010;Husnoo et al 2011). Thus, WASP-12b is an important candidate to measure the apsidal precession.…”