HD 210277 b

HD 210277 b[1]
Discovery
Discovered byMarcy et al.
Discovery siteCalifornia and
Carnegie Planet Search
 USA
Discovery date9 Sept 1998
Radial velocity
Orbital characteristics
1.138 ± 0.066 AU (170,200,000 ± 9,900,000 km)
Eccentricity0.476 ± 0.017
442.19 ± 0.50 d
2,450,104.3 ± 2.6
119.1 ± 2.8
Semi-amplitude38.94 ± 0.75
StarHD 210277

HD 210277 b is an extrasolar planet orbiting the star HD 210277. It was discovered in September 1998 by the California and Carnegie Planet Search team using the highly successful radial velocity method. The planet is at least 24% more massive than Jupiter. The mean distance of the planet from the star is slightly more than Earth's distance from the Sun. However, the orbit is very eccentric, so at periastron this distance is almost halved, and at apastron it is as distant as Mars is from the Sun.[2]

In 2000, a group of scientists proposed, based on preliminary data from the Hipparcos astrometrical satellite, that the planet would have an inclination of 175.8° and a true mass of 18 times Jupiter making it a brown dwarf instead of a planet.[3] However these measurements were later proved useful only for upper limits of inclination.[4] If the planet orbits in the same plane as the claimed circumstellar disk, which seems a plausible assumption, it would have an inclination of 40° and an absolute mass of 2.2 times Jupiter,[5] however later observations failed to confirm the disk's existence.[6][7]

  1. ^ Cite error: The named reference Butler2006 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Marcy1999 was invoked but never defined (see the help page).
  3. ^ Han; Black, David C.; Gatewood, George (2001). "Preliminary Astrometric Masses for Proposed Extrasolar Planetary Companions". The Astrophysical Journal Letters. 548 (1): L57–L60. Bibcode:2001ApJ...548L..57H. doi:10.1086/318927. S2CID 120952927.
  4. ^ Pourbaix, D.; Arenou, F. (2001). "Screening the Hipparcos-based astrometric orbits of sub-stellar objects". Astronomy and Astrophysics. 372 (3): 935–944. arXiv:astro-ph/0104412. Bibcode:2001A&A...372..935P. doi:10.1051/0004-6361:20010597. S2CID 378792.
  5. ^ Cite error: The named reference trilling2000 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Beichman2005 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Bryden2009 was invoked but never defined (see the help page).