Gl 86B: a white dwarf orbits an exoplanet host star

  1. M. Mugrauer*,
  2. R. Neuhäuser*

Article first published online: 1 JUN 2005

DOI: 10.1111/j.1745-3933.2005.00055.x

Issue

Monthly Notices of the Royal Astronomical Society: Letters

Monthly Notices of the Royal Astronomical Society: Letters

Volume 361, Issue 1, pages L15–L19, July 2005

Additional Information

How to Cite

Mugrauer, M. and Neuhäuser, R. (2005), Gl 86B: a white dwarf orbits an exoplanet host star. Monthly Notices of the Royal Astronomical Society: Letters, 361: L15–L19. doi: 10.1111/j.1745-3933.2005.00055.x

Author Information

  1. Astrophysikalisches Institut, Universität Jena, Schillergäßchen 2-3, 07745 Jena, Germany

*★ E-mail: markus@astro.uni-jena.de (MUG); rne@astro.uni-jena.de (NEU)
†Based on observations obtained at the European Southern Observatory on Paranal in ESO programmes 074.C-0262(A) and 070.C-0179(A), the latter taken from the public archive.

Publication History

  1. Issue published online: 1 JUN 2005
  2. Article first published online: 1 JUN 2005
  3. Accepted 2005 April 20. Received 2005 April 20; in original form 2005 March 22

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Keywords:

  • binaries: visual;
  • stars: individual: Gl 86;
  • planetary systems;
  • white dwarfs

ABSTRACT

In this Letter we present our first high-contrast observations of the exoplanet host star Gl 86 using NAOS-CONICA (NACO) and its new Simultaneous Differential Imager (SDI) as well as results from NACO spectroscopy. Els et al. found a faint comoving companion located only ∼2 arcsec east of the exoplanet host star Gl 86A. Our high-contrast SDI observations rule out additional stellar companions from 1 au up to 23 au, and are sensitive for faint T-dwarf companions down to 35 MJup. We present evidence for orbital motion of Gl 86B around the exoplanet host star Gl 86A, which finally confirms that this is a bound binary system. With the given photometry from Els et al. and the NACO spectroscopy obtained, we prove that the companion Gl 86B is a cool white dwarf with an effective temperature of 5000 ± 500 K. This is the first confirmed white dwarf companion to an exoplanet host star and the first observational confirmation that planets survive the post-main-sequence evolution (giant phase and planetary nebula) of a star from which they are separated by only one to two dozen astronomical units, as expected from theory.

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