Anderson, DR, Collier Cameron, A, Delrez, L, Doyle, AP, Gillon, M, Hellier, C, Jehin, E, Lendl, M, Maxted, PFL, Madhusudhan, N, Pepe, F, Pollacco, D, Queloz, D, Ségransan, D, Smalley, B, Smith, AMS, Triaud, AHMJ, Turner, OD, Udry, S and West, RG (2017) The discoveries of WASP-91b, WASP-105b and WASP-107b: Two warm Jupiters and a planet in the transition region between ice giants and gas giants. Astronomy and Astrophysics, 604. A110 - A110. ISSN 1432-0746

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We report the discoveries of three transiting exoplanets. WASP-91b is a warm Jupiter (1.34 MJup, 1.03 RJup) in a 2.8-day orbit around a metal-rich K3 star. WASP-105b is a warm Jupiter (1.8 MJup, 0.96 RJup) in a 7.9-day orbit around a metal-rich K2 star. WASP-107b is a warm super-Neptune/sub-Saturn (0.12 MJup, 0.94 RJup) in a 5.7-day orbit around a solar-metallicity K6 star. Considering that giant planets seem to be more common around stars of higher metallicity and stars of higher mass, it is notable that the hosts are all metal-rich, late-type stars. With orbital separations that place both WASP-105b and WASP-107b in the weak-tide regime, measurements of the alignment between the planets’ orbital axes and their stars’ spin axes may help us to understand the inward migration of short-period, giant planets. The mass of WASP-107b (2.2 MNep, 0.40 MSat) places it in the transition region between the ice giants and gas giants of the Solar System. Its radius of 0.94 RJup suggests that it is a low-mass gas giant with a H/He-dominated composition. The planet thus sets a lower limit of 2.2 MNep on the planetary mass above which large gaseous envelopes can be accreted and retained by proto-planets on their way to becoming gas giants. We may discover whether WASP-107b more closely resembles an ice giant or a gas giant by measuring its atmospheric metallicity via transmission spectroscopy, for which WASP-107b is a very good target.

Item Type: Article
Uncontrolled Keywords: planets and satellites: formation / planets and satellites: individual: WASP-91b / planetary systems / planets and satellites: individual: WASP-105b / planets and satellites: individual: WASP-107b
Subjects: Q Science > QB Astronomy > QB460 Astrophysics
Divisions: Faculty of Natural Sciences > School of Chemical and Physical Sciences
Depositing User: Symplectic
Date Deposited: 31 Aug 2017 10:42
Last Modified: 19 Mar 2019 11:31

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