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Orbital and evolutionary constraints on the planet hosting binary GJ 86 from the Hubble Space Telescope

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posted on 2014-04-24, 10:38 authored by Jay Farihi, H. E. Bond, P. Dufour, N. Haghighipour, G. H. Schaefer, J. B. Holberg, Martin A. Barstow, Matthew R. Burleigh
This paper presents new observations of the planet-hosting, visual binary GJ 86 (HR 637) 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 0.59 M⊙ and descended from a main-sequence A star of 1.9 M⊙ 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 4.7 MJup. 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.

Funding

STFC

History

Citation

Monthly Notices of the Royal Astronomical Society, 2013, 430 (1), pp. 652-660

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

  • VoR (Version of Record)

Published in

Monthly Notices of the Royal Astronomical Society

Publisher

Oxford University Press

issn

0035-8711

eissn

1365-2966

Copyright date

2013

Available date

2014-04-24

Publisher version

http://mnras.oxfordjournals.org/content/430/1/652

Language

en