Stellar obliquities and planetary alignments (SOPA). I. Spin-orbit measurements of three transiting hot Jupiters: WASP-72b, WASP-100b, and WASP-109b

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 degrees(+11)(-12 degrees)degrees, lambda = 79 degrees(+19)(-10 degrees)degrees, and lambda = 99 degrees(+10)(-9 degrees)degrees 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 degrees 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-eff = 6250 +/- 120 K). WASP-100b and WASP-109b are highly irradiated bloated hot Jupiters orbiting hot early-mid F stars (F2 with T-eff = 6900 +/- 120 K and F4 with T-eff = 6520 +/- 140 K), making them consistent with the trends observed for the majority of stars hosting planets on high-obliquity orbits