Stellar Obliquities & Planetary Alignments (SOPA) I. Spin-Orbit measurements of Three Transiting Hot Jupiters: WASP-72b, WASP-100b, & WASP-109b

• Published in: arXiv.org 2018-09
• Main Authors: Addison, B C, Wang, S, Johnson, M C, Tinney, C G, Wright, D J, Bayliss, D
• Format: Article
• Language: English
• Subjects: Extrasolar planets; F stars; Gas giant planets; Jupiter; Optical fibers; Orbits; Polar orbits; Transits
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1809.00314

We report measurements of the sky-projected spin--orbit angles for three transiting hot Jupiters: two of which are in nearly polar orbits, WASP-100b and WASP-109b, and a third in a low obliquity orbit, WASP-72b. We obtained these measurements by observing the Rossiter--McLaughlin effect over the course of the transits from high resolution spectroscopic observations made with the CYCLOPS2 optical fiber bundle system feeding the UCLES spectrograph on the Anglo-Australian Telescope. The resulting sky-projected spin--orbit angles are \(\lambda = {-7^{\circ}}^{+11^{\circ}}_{-12^{\circ}}\), \(\lambda = {79^{\circ}}^{+19^{\circ}}_{-10^{\circ}}\), and \(\lambda = {99^{\circ}}^{+10^{\circ}}_{-9^{\circ}}\) for WASP-72b, WASP-100b, and WASP-109b, respectively. These results suggests that WASP-100b and WASP-109b are on highly inclined orbits tilted nearly \(90^{\circ}\) from their host star's equator while the orbit of WASP-72b appears to be well-aligned. WASP-72b is a typical hot Jupiter orbiting a mid-late F star (F7 with \(T_\mathrm{{eff}}=6250\pm120\)K). WASP-100b and WASP-109b are highly irradiated bloated hot Jupiters orbiting hot early-mid F stars (F2 with \(T_\mathrm{{eff}}=6900\pm120\)K and F4 with \(T_\mathrm{{eff}}=6520\pm140\)K), making them consistent with the trends observed for the majority of stars hosting planets on high-obliquity orbits.