From Dense Hot Jupiter to Low Density Neptune: The Discovery of WASP-127b, WASP-136b and WASP-138b

Lam, K.W.F.; Faedi, F.; Brown, D.J.A.; Anderson, D.R.; Delrez, L.; Gillon, M.; Hébrard, G.; Lendl, M.; Mancini, L.; Southworth, J.; Smalley, B.; Triaud, A.H.M.; Turner, O.D.; Hay, K.L.; Armstrong, D.J.; Barros, S.C.C.; Bonomo, A.S.; Bouchy, F.; Boumis, P.; Collier Cameron, A.; Doyle, A.P.; Hellier, C.; Henning, T.; Jehin, E.; King, G.; Kirk, J.; Louden, T.; Maxted, P.F.L.; McCormac, J.J.; Osborn, H.P.; Palle, E.; Pepe, F.; Pollacco, D.; Prieto-Arranz, J.; Queloz, D.; Rey, J.; Ségransan, D.; Udry, S.; Walker, S.; West, R.G.; Wheatley, P.J.

Abstract

We report three newly discovered exoplanets from the SuperWASP survey. WASP-127b is a heavily inflated super-Neptune of mass 0.18±0.02 MJ and radius 1.37±0.04 RJ. This is one of the least massive planets discovered by the WASP project. It orbits a bright host star (Vmag = 10.16) of spectral type G5 with a period of 4.17 days. WASP-127b is a low-density planet that has an extended atmosphere with a scale height of 2500 ± 400 km, making it an ideal candidate for transmission spectroscopy. WASP-136b and WASP-138b are both hot Jupiters with mass and radii of 1.51 ± 0.08 MJ and 1.38 ± 0.16 RJ, and 1.22 ± 0.08 MJ and 1.09 ± 0.05 RJ, respectively. WASP-136b is in a 5.22-day orbit around an F9 subgiant star with a mass of 1.41 ± 0.07 M? and a radius of 2.21 ± 0.22 R?. The discovery of WASP-136b could help constrain the characteristics of the giant planet population around evolved stars. WASP-138b orbits an F7 star with a period of 3.63 days. Its radius agrees with theoretical values from standard models, suggesting the presence of a heavy element core with a mass of ~ 10 M?. The discovery of these new planets helps in exploring the diverse compositional range of short-period planets, and will aid our understanding of the physical characteristics of both gas giants and low-density planets.

Citation

Lam, K., Faedi, F., Brown, D., Anderson, D., Delrez, L., Gillon, M., …Wheatley, P. (2017). From Dense Hot Jupiter to Low Density Neptune: The Discovery of WASP-127b, WASP-136b and WASP-138b. Astronomy and Astrophysics, 599, Article A3. https://doi.org/10.1051/0004-6361/201629403

• Journal Article Type: Article
• Acceptance Date: Oct 20, 2016
• Online Publication Date: Feb 20, 2017
• Publication Date: 2017-03
• Publicly Available Date: May 26, 2023
• Journal: Astronomy and Astrophysics
• Print ISSN: 2329-1273
• Publisher: Hans Publishers
• Peer Reviewed: Peer Reviewed
• Volume: 599
• Article Number: A3
• DOI: https://doi.org/10.1051/0004-6361/201629403
• Keywords: Planetary systems, Stars, individual, WASP-127, WASP-136, WASP-138, Techniques, radial velocities, photometric
• Publisher URL: http://dx.doi.org/10.1051/0004-6361/201629403