WASP-34b: a near-grazing transiting sub-Jupiter-mass exoplanet in a hierarchical triple system

B. Smalley*, D. R. Anderson, A. Collier Cameron, C. Hellier, M. Lendl, P. F L Maxted, D. Queloz, A. H M J Triaud, R. G. West, S. J. Bentley, B. Enoch, M. Gillon, T. A. Lister, F. Pepe, D. Pollacco, D. Segransan, A. M S Smith, J. Southworth, S. Udry, P. J. WheatleyP. L. Wood, J. Bento

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)


We report the discovery of WASP-34b, a sub-Jupiter-mass exoplanet transiting its 10.4-magnitude solar-type host star (1SWASP J110135.89-235138.4; TYC 6636-540-1) every 4.3177 days in a slightly eccentric orbit (e = 0.038±0.012). We find a planetary mass of 0.59±0.01 M Jup and radius of 1.22-0.08 +0.11 R Jup. There is a linear trend in the radial velocities of 55±4 m s-1 y-1 indicating the presence of a long-period third body in the system with a mass ≥0.45 MJup at a distance of ≥1.2 AU from the host star. This third-body is either a low-mass star, a white dwarf, or another planet. The transit depth ((RP/R*) 2 = 0.0126) and high impact parameter (b = 0.90) suggest that this could be the first known transiting exoplanet expected to undergo grazing transits, but with a confidence of only ~80%.

Original languageEnglish
Article numberA130
Pages (from-to)1-5
Number of pages5
JournalAstronomy and Astrophysics
Issue number16
Publication statusPublished - Feb 2011
Externally publishedYes


  • planets and satellites: general
  • stars: individual: WASP-34
  • techniques: photometric
  • techniques: radial velocities
  • techniques: spectroscopic


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