Open AccessGl 86B: a white dwarf orbits an exoplanet host star
Author(s) -
Mugrauer M.,
Neuhäuser R.
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society: letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.067
H-Index - 122
eISSN - 1745-3933
pISSN - 1745-3925
DOI - 10.1111/j.1745-3933.2005.00055.x
Subject(s) - physics , exoplanet , white dwarf , astrophysics , astronomy , photometry (optics) , planet , proper motion , stars
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 M Jup . 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.