A HIGH STELLAR OBLIQUITY IN THE WASP-7 EXOPLANETARY SYSTEM

作者：Albrecht Simon^*; Winn Joshua N; Butler R Paul; Crane Jeffrey D; Shectman Stephen A; Thompson Ian B; Hirano Teruyuki; Wittenmyer Robert A

来源：Astrophysical Journal, 2012, 744(2): 189.

DOI：10.1088/0004-637X/744/2/189

• planetary systems
• planets and satellites: formation
• planet-star interactions
• stars: individual (WASP-7)
• stars: rotation
• techniques: spectroscopic

We measure a tilt of 86 degrees +/- 6 degrees. between the sky projections of the rotation axis of the WASP-7 star and the orbital axis of its close-in giant planet. This measurement is based on observations of the Rossiter-McLaughlin (RM) effect with the Planet Finder Spectrograph on the Magellan II telescope. The result conforms with the previously noted pattern among hot-Jupiter hosts, namely, that the hosts lacking thick convective envelopes have high obliquities. Because the planet%26apos;s trajectory crosses a wide range of stellar latitudes, observations of the RM effect can in principle reveal the stellar differential rotation profile; however, with the present data the signal of differential rotation could not be detected. The host star is found to exhibit radial-velocity noise (%26quot;stellar jitter%26quot;) with an amplitude of approximate to 30 m s(-1) over a timescale of days.

• 出版日期2012-1-10