HD 203857

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HD 203857
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cygnus
Right ascension 21h 21m 46.81s
Declination +37° 08′ 10.2″
Apparent magnitude (V) 6.45
Characteristics
Spectral type K5III
Astrometry
Distance ≈919.32 ly
(282±50 pc)
Details
Mass 1.7 [1] M
Radius 46-50[1] R
Luminosity 513[1] L
Temperature 3980[1] K
Other designations
HIP 105637, CSI+36 4543 1, HIC 105637, SAO 71280, AG+37 2110, GC 29966, HR 8193, SKY# 40762, BD+36 4543, GCRV 13462, IDS 21197+3655 A, TYC 2715-3976-1, BDS 10966 A, GSC 02715-03976, 2MASS J21234838+3721052, CCDM J21237+3722A, HD 203857, PPM 86485

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[edit]

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 planetary system
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b (unconfirmed) ≥8.1 MJ 2.1 836.8 0.3

References[edit]

  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. doi:10.1093/pasj/61.1.19. 

External links[edit]