HD 210277 b [1]
Extrasolar planet List of extrasolar planets
Parent star

<tr> <td colspan="2">Star</td> <td>HD 210277</td></tr><tr> <td colspan="2">Constellation</td> <td>Aquarius</td></tr><tr> <td>Right ascension</td> <td style="text-align: center">(α)</td> <td>22h 09m 29.8657s</td></tr><tr> <td>Declination</td> <td style="text-align: center">(δ)</td> <td>−07° 32′ 55.155″</td></tr><tr> <td>Apparent magnitude</td> <td style="text-align: center">(mV)</td> <td>6.63</td></tr><tr><td colspan="2">Distance</td><td>69.44 ly
(21.29 pc)</td></tr><tr><td colspan="2">Spectral type</td> <td>G0V</td></tr>

Orbital elements

<tr><td>Semimajor axis</td><td style="text-align: center">(a)</td> <td>1.138 ± 0.066 AU
(170.2 Gm)</td></tr><tr><td> </td> <td style="text-align: center"> </td> <td>53.45 mas</td></tr><tr> <td>Periastron</td> <td style="text-align: center">(q)</td> <td>0.596 AU
(89.2 Gm)</td></tr><tr> <td>Apastron</td> <td style="text-align: center">(Q)</td> <td>1.680 AU
(251.3 Gm)</td></tr><tr> <td>Eccentricity</td> <td style="text-align: center">(e)</td> <td>0.476 ± 0.017</td></tr><tr><td>Orbital period</td><td style="text-align: center">(P)</td> <td>442.19 ± 0.50 d
(1.2106 y)</td></tr><tr> <td>Orbital speed</td> <td style="text-align: center">(υ)</td> <td>28.09 km/s</td></tr><tr> <td>Argument of
</td> <td style="text-align: center">(ω)</td> <td>119.1 ± 2.8°</td></tr><tr> <td>Time of periastron</td> <td style="text-align: center">(T0)</td> <td>2,450,104.3 ± 2.6 JD</td></tr><tr> <td>Semi-amplitude</td> <td style="text-align: center">(K)</td> <td>38.94 ± 0.75 m/s</td></tr>

Physical characteristics

<tr><td>Minimum mass</td><td style="text-align: center">(m sin i)</td><td>1.29 ± 0.11 MJ</td></tr>

Discovery information

<tr> <td colspan="2">Discovery date</td> <td>9 Sept 1998</td></tr><tr> <td colspan="2">Discoverer(s)</td> <td>Marcy et al.</td></tr><tr> <td colspan="2">Discovery method</td> <td>Radial velocity</td></tr><tr> <td colspan="2">Discovery site</td> <td>California and
Carnegie Planet Search

Template:Country data USA</td></tr><tr> <td colspan="2">Discovery status</td> <td>Published</td></tr> <tr style="background-color: #A0B0FF;"><td align=center colspan=3>Database references</td></tr><tr valign=baseline><td colspan=2>Extrasolar Planets
</td><td>data</td></tr><tr><td colspan=2>SIMBAD</td><td>data</td></tr>

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][8]


  1. (2006). Catalog of Nearby Exoplanets. The Astrophysical Journal 646 (1): 505–522.
  2. Marcy et al. (1999). Two New Candidate Planets in Eccentric Orbits. The Astrophysical Journal 520 (1): 239–247.
  3. Han et al. (2001). Preliminary Astrometric Masses for Proposed Extrasolar Planetary Companions. The Astrophysical Journal Letters 548 (1): L57–L60.
  4. Pourbaix, D. and Arenou, F. (2001). Screening the Hipparcos-based astrometric orbits of sub-stellar objects. Astronomy and Astrophysics 372 (3): 935–944.
  5. Trilling et al. (2000). Circumstellar Dust Disks around Stars with Known Planetary Companions. The Astrophysical Journal 529 (1): 499–505.
  6. Beichman, C. A.; Bryden, G.; Rieke, G. H.; Stansberry, J. A.; Trilling, D. E.; Stapelfeldt, K. R.; Werner, M. W.; Engelbracht, C. W.; Blaylock, M.; Gordon, K. D.; Chen, C. H.; Su, K. Y. L.; Hines, D. C. (2005). Planets and Infrared Excesses: Preliminary Results from a Spitzer MIPS Survey of Solar-Type Stars. The Astrophysical Journal 622 (2): 1160–1170.
  7. Bryden, G.; Beichman, C. A.; Carpenter, J. M.; Rieke, G. H.; Stapelfeldt, K. R.; Werner, M. W.; Tanner, A. M.; Lawler, S. M.; Wyatt, M. C.; Trilling, D. E.; Su, K. Y. L.; Blaylock, M.; Stansberry, J. A. (2009). Planets and Debris Disks: Results from a Spitzer/MIPS Search for Infrared Excess. The Astrophysical Journal 705 (2): 1226–1236.
  8. Caer McCabe & Carlotta Pham. Catalog of withdrawn or refuted resolved Disks. Catalog of Resolved Circumstellar Disks. Retrieved 2010-04-03.

External links Edit

Coordinates: Sky map 22h 09m 29.8657s, −07° 32′ 55.155″ Template:Nearest bright star systems

de:HD 210277 b

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