Hodžić, V, Triaud, AHMJ, Anderson, DR, Bouchy, F, Cameron, AC, Delrez, L, Gillon, M, Hellier, C, Jehin, E, Lendl, M, Maxted, PFL, Pepe, F, Pollacco, D, Queloz, D, Ségransan, D, Smalley, B, Udry, S and West, R (2018) WASP-128b: a transiting brown dwarf in the dynamical-tide regime. Monthly Notices of the Royal Astronomical Society, 481 (4). pp. 5091-5097. ISSN 1365-2966

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Massive companions in close orbits around G dwarfs are thought to undergo rapid orbital decay due to runaway tidal dissipation. We report here the discovery of WASP-128b, a brown dwarf discovered by the WASP survey transiting a G0V host on a 2.2 d orbit, where the measured stellar rotation rate places the companion in a regime where tidal interaction is dominated by dynamical tides. Under the assumption of dynamical equilibrium, we derive a value of the stellar tidal quality factor logQ′⋆=6.96±0.19. A combined analysis of ground-based photometry and high-resolution spectroscopy reveals a mass and radius of the host, M⋆ = 1.16 ± 0.04M⊙, R⋆ = 1.16 ± 0.02R⊙, and for the companion, Mb = 37.5 ± 0.8Mj, Rb = 0.94 ± 0.02Rj, placing WASP-128b in the driest parts of the brown dwarf desert, and suggesting a mild inflation for its age. We estimate a remaining lifetime for WASP-128b similar to that of some ultra-short period massive hot Jupiters, and note it may be a propitious candidate for measuring orbital decay and testing tidal theories.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2018 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords: methods, data analysis, brown dwarfs, binaries, eclipsing, planets and satellites, dynamical evolution and stability
Subjects: Q Science > QB Astronomy > QB460 Astrophysics
Divisions: Faculty of Natural Sciences > School of Chemical and Physical Sciences
Depositing User: Symplectic
Date Deposited: 27 Sep 2018 10:12
Last Modified: 18 Jan 2019 09:32
URI: https://eprints.keele.ac.uk/id/eprint/5373

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