Orbital and evolutionary constraints on the planet hosting binary GJ 86 from the Hubble space telescope

J. Farihi, Howard E. Bond, P. Dufour, N. Haghighipour, G. H. Schaefer, J. B. Holberg, M. A. Barstow, M. R. Burleigh

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24 Scopus citations


This paper presents newobservations of the planet-hosting, visual binary GJ 86 (HR637) using the Hubble Space Telescope. Ultraviolet and optical imaging with WFC3 confirms the stellar companion is a degenerate star and indicates the binary semimajor axis is larger than previous estimates, with a ≥ 28 au. Optical STIS spectroscopy of the secondary reveals a helium-rich white dwarf with C2 absorption bands and Teff = 8180 K, thus making the binary system rather similar to Procyon. Based on the 10.8 pc distance, the companion has 0.59M and descended from a main-sequence A star of 1.9M with an original orbital separation a ≥ 14 au. If the giant planet is coplanar with the binary, the mass of GJ 86Ab is between 4.4 and 4.7MJup. The similarity of GJ 86 and Procyon prompted a re-analysis of the white dwarf in the latter system, with the tentative conclusion that Procyon hosts a planetesimal population. The periastron distance in Procyon is 20 per cent smaller than in α Cen AB, but the metal-enriched atmosphere of Procyon B indicates that the planet formation process minimally attained 25 km bodies, if not small planets as in α Cen.

Original languageEnglish (US)
Pages (from-to)652-660
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - Mar 21 2013

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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