Transiting planets from WASP-South, Euler, and TRAPPIST : WASP-68 b, WASP-73 b, and WASP-88 b, three hot Jupiters transiting evolved solar-type stars
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Using the WASP transit survey, we report the discovery of three new hot Jupiters, WASP-68 b, WASP-73 b and WASP-88 b. The planet WASP-68 b has a mass of 0.95 ± 0.03 MJup, a radius of 1.24-0.06+0.10 RJup, and orbits a V = 10.7 G0-type star (1.24 ± 0.03 M⊙ 1.69-0.06+0.11 R⊙, Teff = 5911 ± 60 K) with a period of 5.084298 ± 0.000015 days. Its size is typical of hot Jupiters with similar masses. The planet WASP-73 bis significantly more massive (1.88-0.06+0.07 MJup) and slightly larger (1.16-0.08+0.12 RJup) than Jupiter. It orbits a V = 10.5 F9-type star (1.34-0.04+0.05 M⊙, 2.07-0.08+0.19 R⊙, Teff = 6036 ± 120 K) every 4.08722 ± 0.00022 days. Despite its high irradiation (~2.3 × 109 erg s-1 cm-2), WASP-73 b has a high mean density (1.20-0.30+0.26 ρJup) that suggests an enrichment of the planet in heavy elements. The planet WASP-88 bis a 0.56 ± 0.08 MJuphot Jupiter orbiting a V = 11.4 F6-type star (1.45 ± 0.05 M⊙, 2.08-0.06+0.12 R⊙, Teff = 6431 ± 130 K) with a period of 4.954000 ± 0.000019 days. With a radius of 1.70-0.07+0.13 RJup, it joins the handful of planets with super-inflated radii. The ranges of ages we determine through stellar evolution modeling are 4.5–7.0 Gyr for WASP-68, 2.8-5.7 Gyr for WASP-73 and 1.8–4.3 Gyr for WASP-88. The star WASP-73 appears to be significantly evolved, close to or already in the subgiant phase. The stars WASP-68 and WASP-88 are less evolved, although in an advanced stage of core H-burning.
Delrez , L , Van Grootel , V , Anderson , D R , Collier-Cameron , A , Doyle , A P , Fumel , A , Gillon , M , Hellier , C , Jehin , E , Lendl , M , Neveu-VanMalle , M , Maxted , P F L , Pepe , F , Pollacco , D , Queloz , D , Ségransan , D , Smalley , B , Smith , A M S , Southworth , J , Triaud , A H M J , Udry , S & West , R G 2014 , ' Transiting planets from WASP-South, Euler, and TRAPPIST : WASP-68 b, WASP-73 b, and WASP-88 b, three hot Jupiters transiting evolved solar-type stars ' Astronomy & Astrophysics , vol 563 , A143 . DOI: 10.1051/0004-6361/201323204
Astronomy & Astrophysics
© ESO, 2014