HD 190228
|
Stern HD 190228 |
|||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| AladinLite | |||||||||||||
|
Observation dates equinox : J2000.0 , epoch : J2000.0 |
|||||||||||||
| Constellation | Fox | ||||||||||||
| Right ascension | 20 h 03 m 0.8 s | ||||||||||||
| declination | + 28 ° 18 ′ 25 ″ | ||||||||||||
| Apparent brightness | 7.3 likes | ||||||||||||
| Typing | |||||||||||||
| Spectral class | G5 IV | ||||||||||||
| Astrometry | |||||||||||||
| Radial velocity | (−50.3 ± 0.2) km / s | ||||||||||||
| parallax | (16.23 ± 0.64) mas | ||||||||||||
| distance | (201 ± 8) ly (61.6 ± 2.4) pc |
||||||||||||
| Visual absolute brightness M vis | +3.4 mag | ||||||||||||
| Proper movement | |||||||||||||
| Rec. Share: | (+105.20 ± 0.33) mas / a | ||||||||||||
| Dec. portion: | (−69.82 ± 0.48) mas / a | ||||||||||||
| Physical Properties | |||||||||||||
| Dimensions | 0.8 M ☉ | ||||||||||||
| Effective temperature | (5360 ± 40) K. | ||||||||||||
| Metallicity [Fe / H] | −0.24 ± 0.06 | ||||||||||||
| Age | > 10 billion a | ||||||||||||
|
Other names and catalog entries |
|||||||||||||
|
|||||||||||||
HD 190228 is a star around 200 light years (approx. 62 parsecs ) away from the Sun with an apparent visual magnitude of 7.3 mag in the constellation Vulpecula . The star is a sub-giant of the spectral class G and is over 10 billion years old. It is circled by a substellar companion called HD 190228 b (or HD 190228 B ), which is likely to be a brown dwarf (or possibly a low-mass star).
companion
The discovery of the companion of HD 190228 was made using the radial velocity method and was published in 2000. Its determined low minimum mass of 5 Jupiter made it an exoplanet candidate. With the determination of the orbit inclination of about 4 °, however, it was shown that the mass of the companion is significantly higher and is around (49 ± 15) Jupiter's masses. The orbital period of the companion is a little over 1100 days, its orbit has an eccentricity of 0.5.
swell
- Chen et al .: The companion of HD 190228: Planet or brown dwarf? . In: Astron. Astrophys . 374, 2001, pp. L1-L4. bibcode : 2001A & A ... 374L ... 1C .
- Sivan et al .: A planetary companion to HD 190228 . In: Planetary Systems in the Universe . 2004, p. 124. bibcode : 2004IAUS..202..124S .
Web links
- Notes for star HD 190228 . In: The Extrasolar Planets Encyclopaedia . Retrieved December 16, 2007.
- Notes for planet HD 190228 b . In: The Extrasolar Planets Encyclopaedia . Retrieved December 16, 2007.
- HD 190228 - Yellow Subgiant Star . In: Extrasolar Visions . Retrieved December 16, 2007.
- HD 190228 B - Water Cloud Jovian, Eccentric . In: Extrasolar Visions . Retrieved December 16, 2007.
- HD 190228 - Star . In: SIMBAD . Retrieved December 16, 2007.
- HD 190228 - Extra-solar Planet Candidate . In: SIMBAD . Retrieved December 16, 2007.
Individual evidence
- ↑ a b c Hipparcos catalog (ESA 1997)
- ↑ Pulkovo radial velocities for 35493 HIP stars
- ↑ a b c Hipparcos, the New Reduction (van Leeuwen, 2007)
- ↑ estimated from apparent brightness and distance