From dense hot Jupiter to low-density Neptune: the discovery of WASP-127b, WASP-136b, and WASP-138b

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

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


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.

Original languageEnglish
Article numberA3
Number of pages10
JournalAstronomy & Astrophysics
Early online date20 Feb 2017
Publication statusPublished - 1 Mar 2017


  • Planetary systems
  • Stars: individual: WASP-127
  • Stars: individual: WASP-136
  • Stars: individual: WASP-138
  • Techniques: photometric
  • Techniques: radial velocities


Dive into the research topics of 'From dense hot Jupiter to low-density Neptune: the discovery of WASP-127b, WASP-136b, and WASP-138b'. Together they form a unique fingerprint.

Cite this