Hellenica World

HD 203857

HD 203857 is a late type K giant star in the constellation Cygnus, located nearly 920 light years away from Sun. The star is thought to form a visual binary system with the F-type bright giant BDS 10966 A, though it's likely they are actually not gravitationally bound. The star likely hosts an extrasolar planet, though yet unconfirmed.

Substellar companion

Okayama Planet Search team has published a paper in late 2008 reporting investigations on radial velocity variations observed for a set of evolved stars, announcing possible detection of a substellar companion orbiting the giant star HD 203857.[1] Orbital period is estimated 2.3 years, but planet has still to be confirmed.

The HD 203857 system
(in order from star)
Mass Semimajor axis
Orbital period
b (unconfirmed) ≥8.1 MJ 2.1 836.8 0.3


1. ^ a b c d e Toyota et al. (2008). "Radial Velocity Search for Extrasolar Planets in Visual Binary Systems". Publications of the Astronomical Society of Japan 61 (1): 19–28. Bibcode: 2009PASJ...61...19T. http://adsabs.harvard.edu/abs/2009PASJ...61...19T.

External links

* http://exoplanet.eu/star.php?st=HD%20203857

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