HD 210277
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| Observation data Epoch 2000 |
|
|---|---|
| Constellation | Aquarius |
| Right ascension | 22h 9m 29.87s |
| Declination | -7° 32' 55.16" |
| Apparent magnitude (V) | 6.63 |
| Distance | 69.41 ly (21.29 pc) |
| Spectral type | G0V |
| Other designations | |
|
GJ 848.4, BD-08°5818,
HIP 109378 |
|
HD 210277 is a 7th magnitude star in the constellation Aquarius. It is a yellow dwarf star (spectral type G0V) like our Sun. It has a mass around 0.92 times that of our Sun and is estimated to be around 12 billion years old[1]. Since its distance is about 69 light years, it is not visible to the unaided eye. With binoculars it is easily visible.
The star has a massive extrasolar planet orbiting it. Also, in 1999 the discovery of a circumstellar disk was announced by T. E. Trilling et al. based on observations in infrared wavelengths. The disk is probably similar to the Kuiper belt in our Solar system.
Contents |
[edit] HD 210277 b
| Extrasolar planet | Lists of extrasolar planets | |
|---|---|---|
| Orbital elements | ||
| Semimajor axis | (a) | 1.138 ± 0.066 AU |
| Eccentricity | (e) | 0.476 ± 0.017 |
| Orbital period | (P) | 442.19 ± 0.50 d |
| Inclination | (i) | ?° |
| Longitude of periastron |
(ω) | 119.1 ± 2.8° |
| Time of periastron | (τ) | 2,450,104.3 ± 2.6 JD |
| Physical characteristics | ||
| Mass | (m) | >1.29 ± 0.11 MJ |
| Radius | (r) | ? RJ |
| Density | (ρ) | ? kg/m3 |
| Temperature | (T) | ? K |
| Discovery information | ||
| Discovery date | 1998 | |
| Discoverer(s) | Marcy et al. | |
| Detection method | Radial velocity | |
| Discovery status | Confirmed | |
HD 210277 was discovered in 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[3].
In 2000 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[4]. However, it is statistically very improbable, and the claim has not been confirmed. If the planet orbits in the same plane as the circumstellar disk, which seems a plausible assumption, it would have an inclination of 40° and an absolute mass of 2.2 times Jupiter[5].
[edit] HD 210277 dust disk
A dust disk around the star HD 210277, similar to that produced by the Kuiper Belt in our solar system was imaged in 1999. It lies between 30 and 62 AU from the star and is estimated to be between 50 and 80 times as massive as our solar system's Kuiper Belt[5].
[edit] References
- ^ G. Gonzalez, G. Wallerstein, S.H. Saar (1999). "Parent Stars of Extrasolar Planets. IV. 14 Herculis, HD 187123, and HD 210277". Astrophysical Journal 511: L111 – L114.
- ^ Butler, R. et al. (2006). "Catalog of Nearby Exoplanets". The Astrophysical Journal 646: 505 – 522. (web version)
- ^ G.W. Marcy, R.P. Butler, S.S. Vogt, D. Fischer, M.C. Liu (1999). "Two New Candidate Planets in Eccentric Orbits". Astrophysical Journal 520: 239 – 247.
- ^ I. Han, D.C. Black, G. Gatewood (2001). "Preliminary Astrometric Masses for Proposed Extrasolar Planetary Companions". Astrophysical Journal 548: L57 – L60.
- ^ a b D.E. Trilling, R.H. Brown, A.S. Rivkin (2000). "Circumstellar Dust Disks around Stars with Known Planetary Companions". Astrophysical Journal 529: 499 – 505.
