Faedi, F, Gómez Maqueo Chew, Y, Pollacco, D, Brown, DJA, Hebrard, G, Smalley, B, Lam, KWF, Veras, D, Anderson, D, Doyle, AP, Gillon, M, Goad, MR, Lendl, M, Mancini, L, McCormac, J, Plauchu-Frayn, I, Prieto-Arranz, J, Scholz, A, Street, R, Triaud, AHM, West, R, Wheatley, PJ, Armstrong, DJ, Barros, SCC, Boisse, I, Bouchy, F, Boumis, P, Collier Cameron, A, Haswell, CA, Hay, KL, Hellier, C ORCID: https://orcid.org/0000-0002-3439-1439, Kolb, U, Maxted, PFL, Norton, AJ, Osborn, HP, Palle, E, Pepe, F, Queloz, D, Segransan, D, Udry, S and Wilson, PA (2016) WASP-86b and WASP-102b: super-dense versus bloated planets. arXiv.

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Abstract

We report the discovery of two transiting planetary systems: a super dense, sub-Jupiter mass planet WASP-86b (Mpl = 0.82 ± 0.06 MJ; Rpl = 0.63 ± 0.01 RJ), and a bloated, Saturn-like planet WASP-102b (Mpl = 0.62 ± 0.04 MJ; Rpl = 1.27 ± 0.03 RJ). They orbit their host star every ∼5.03, and ∼2.71 days, respectively. The planet hosting WASP-86 is a F7 star (Teff = 6330±110 K, [Fe/H] = +0.23 ± 0.14 dex, and age ∼0.8–1 Gyr); WASP-102 is a G0 star (Teff = 5940±140 K, [Fe/H] = −0.09± 0.19 dex, and age ∼1 Gyr). These two systems highlight the diversity of planetary radii over similar masses for giant planets with masses between Saturn and Jupiter. WASP-102b shows a larger than model-predicted radius, indicating that the planet is receiving a strong incident flux which contributes to the inflation of its radius. On the other hand, with a density of ρpl = 3.24± 0.3 ρJ, WASP-86b is the densest gas giant planet among planets with masses in the range 0.05 < Mpl < 2.0 MJ. With a stellar mass of 1.34 M⊙ and [Fe/H]= +0.23 dex, WASP-86 could host additional massive and dense planets given that its protoplanetary disc is expected to also have been enriched with heavy elements. In order to match WASP-86b’s density, an extrapolation of theoretical models predicts a planet composition of more than 80% in heavy elements (whether confined in a core or mixed in the envelope). This fraction corresponds to a core mass of approximately 210M⊕ for WASP-86b’s mass of Mpl∼260 M⊕. Only planets with masses larger than about 2 MJ have larger densities than that of WASP-86b, making it exceptional in its mass range.

Item Type: Article
Additional Information: First published in arXiv repository, August 2016.
Uncontrolled Keywords: planetary systems, stars, individual. (WASP-86, WASP-102), techniques, radial velocity, photometry
Subjects: Q Science > QB Astronomy > QB460 Astrophysics
Divisions: Faculty of Natural Sciences > School of Chemical and Physical Sciences
Depositing User: Symplectic
Date Deposited: 28 Mar 2018 09:08
Last Modified: 21 Feb 2019 14:30
URI: https://eprints.keele.ac.uk/id/eprint/4650

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