Spin-orbit alignments for Three Transiting Hot Jupiters: WASP-103b, WASP-87b, & WASP-66b

• Published in: arXiv.org
• Main Authors: Addison, B C, Tinney, C G, Wright, D J, Bayliss, D
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 23.05.2016
• Subjects: Alignment; Extrasolar planets; F stars; Gas giant planets; Orbits; Physics - Earth and Planetary Astrophysics; Retrograde orbits; Tidal effects
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1603.05754

We have measured the sky-projected spin-orbit alignments for three transiting Hot Jupiters, WASP-103b, WASP-87b, and WASP-66b, using spectroscopic measurements of the Rossiter-McLaughlin effect, with the CYCLOPS2 optical-fiber bundle system feeding the UCLES spectrograph on the Anglo-Australian Telescope. The resulting sky projected spin-orbit angles of \(\lambda = 3^{\circ}\pm33^{\circ}\), \(\lambda = -8^{\circ}\pm11^{\circ}\), and \(\lambda = -4^{\circ}\pm22^{\circ}\) for WASP-103b, WASP-87b, and WASP-66b, respectively, suggest that these three planets are likely on nearly aligned orbits with respect to their host star's spin axis. WASP-103 is a particularly interesting system as its orbital distance is only 20% larger than its host star's Roche radius and the planet likely experiences strong tidal effects. WASP-87 and WASP-66 are hot (\(T_{eff}=6450\pm120\) K and \(T_{eff}=6600\pm150\) K, respectively) mid-F stars making them similar to the majority of stars hosting planets on high obliquity orbits. Moderate spin-orbit misalignments for WASP-103b and WASP-66b are consistent with our data, but polar and retrograde orbits are not favored for these systems.