| 词条 | HD 203857 |
| 释义 |
| name = HD 203857 }}{{Starbox observe | epoch = J2000.0 | constell = Cygnus | ra={{RA|21|21|46.81}} | dec={{DEC|+37|08|10.2}} | appmag_v = 6.45 }}{{Starbox character | class = K5III }}{{Starbox astrometry | dist_ly = ≈919.32 | dist_pc = 282±50 }}{{Starbox detail | mass = 1.7 [1] | radius = 46-50[1] | luminosity = 513[1] | temperature = 3980[1] }}{{Starbox catalog | names = HD 203857, HIP 105637, SAO 71280, HR 8193, BD+36° 4543, CCDM J21237+3722A }}{{Starbox reference | Simbad = HD+203857 }}{{Starbox end}} HD 203857 is a late type K giant star in the constellation Cygnus, located nearly 920 light years away from the 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 companionOkayama 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. {{OrbitboxPlanet begin}}{{OrbitboxPlanet hypothetical| exoplanet = b | mass = ≥8.1 | period = 836.8 | semimajor = 2.1 | eccentricity = 0.3 }}{{Orbitbox end}} References1. ^1 2 3 4 {{cite journal| author=Toyota | display-authors=etal | title=Radial Velocity Search for Extrasolar Planets in Visual Binary Systems| journal=Publications of the Astronomical Society of Japan | volume=61| issue=1 | pages=19–28| year=2008 | bibcode=2009PASJ...61...19T|doi = 10.1093/pasj/61.1.19 }} External links
7 : Cygnus (constellation)|K-type giants|Henry Draper Catalogue objects|Hipparcos objects|HR objects|Hypothetical planetary systems|Durchmusterung objects |
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