HD 202206
| Observation data Epoch J2000.0 Equinox J2000.0 |
|
|---|---|
| Constellation | Capricornus |
| Right ascension | 21h 14m 57.769s |
| Declination | −20° 47′ 21.15″ |
| Apparent magnitude (V) | +8.08 |
| Characteristics | |
| Spectral type | G6V |
| U−B color index | ? |
| B−V color index | 0.714 |
| Variable type | none |
| Astrometry | |
| Radial velocity (Rv) | ? km/s |
| Proper motion (μ) |
RA: -38.40 ± 0.94 mas/yr Dec.: -119.81 ± 0.37 mas/yr |
| Parallax (π) | 22.06 ± 0.82mas |
| Distance | 148 ± 5 ly (45 ± 2 pc) |
| Absolute magnitude (MV) | +4.75 |
| Details | |
| Mass | 1.15 M☉ |
| Radius | 1.02 R☉ |
| Luminosity | 1.07 L☉ |
| Temperature | 5765 ± 40 K |
| Metallicity | 234% |
| Rotation | ? |
| Age | (5.6 ± 1.2) × 109 years |
| Other designations | |
|
HIP 104903
|
|
| Database references | |
| SIMBAD | data |
HD 202206 is a yellow dwarf star approximately 148 light-years away in the constellation Capricornus. The star is orbited by a brown dwarf and a planetary companion in a 5:1 resonant configuration.
Measurements by the Hipparcos astrometric satellite give a parallax of 22.06 milliarcseconds, which corresponds to a distance of 45 parsecs. It is similar in mass, radius, and luminosity to the Sun, though estimated to be older at around 5.6 Gyr old. It is also more metal-rich than our Sun based on the amount of iron relative to hydrogen.
In 2000, analysis of radial velocity measurements of the star revealed the existence of a brown dwarf companion (designated HD 202206 b) with at least 17 times the mass of Jupiter around the star in an eccentric orbit with a period of around 256 days. This mass exceeds the 13 Jupiter mass limit above which an object can undergo deuterium fusion in its core, which some take to be the dividing line between planets and brown dwarfs, a definition which is supported by the IAU. However, some authors have suggested that the core accretion process (the traditional model for planet formation) can form objects above this limit, up to around 25–30 Jupiter masses. The classification of HD 202206 b as a brown dwarf or "superplanet" is currently unclear.
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