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

20 Citations (Scopus)


We report three newly discovered exoplanets from the SuperWASP survey. WASP-127b is a heavily inflated super-Neptune of mass 0.18plusmn0.02 M$_J$ and radius 1.37plusmn0.04 R$_J$. This is one of the least massive planets discovered by the WASP project. It orbits a bright host star (V$_mag$ = 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 plusmn 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 plusmn 0.08 M$_J$ and 1.38 plusmn 0.16 R$_J$, and 1.22 plusmn 0.08 M$_J$ and 1.09 plusmn 0.05 R$_J$, respectively. WASP-136b is in a 5.22-day orbit around an F9 subgiant star with a mass of 1.41 plusmn 0.07 M$_⊙$ and a radius of 2.21 plusmn 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. Radial velocity and photometry tables are only available at the CDS via anonymous ftp to ( or via
Original languageEnglish
Pages (from-to)A3
JournalAstronomy and Astrophysics
Early online date20 Feb 2017
Publication statusPublished - 1 Mar 2017


  • stars: individual: WASP-138
  • planetary systems
  • stars: individual: WASP-127
  • techniques: radial velocities
  • techniques: photometric
  • stars: individual: WASP-136


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