HD 21389
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Camelopardalis |
| Right ascension | 03h 29m 54.7438s |
| Declination | +58° 52′ 43.499″ |
| Apparent magnitude (V) | 4.6 |
| Characteristics | |
| Spectral type | A0Iab: |
| U−B color index | -0.11 |
| B−V color index | 0.56 |
| R−I color index | 0.5 |
| Variable type | Alpha Cygni variable |
| Astrometry | |
| Radial velocity (Rv) | -6 km/s |
| Proper motion (μ) | RA: 1.94 mas/yr Dec.: -1.14 mas/yr |
| Parallax (π) | 1.32 ± 0.72 mas |
| Distance | approx. 2,000 ly (approx. 800 pc) |
| Absolute magnitude (MV) | -4.85 |
| Details | |
| Mass | 15.5 ± 0.8[1] M☉ |
| Luminosity | 62679[2] L☉ |
| Temperature | 9730[2] K |
| Age | 11.6 ± 0.5 million[1] years |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Data sources: | |
| Hipparcos Catalogue, CCDM (2002), Bright Star Catalogue (5th rev. ed.) | |
HD 21389 is a variable star in reflection nebula VDB 15, in the constellation Camelopardalis. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[3] It is some 15 times as massive as the Sun. Only around 11 to 12 million years old, it has exhausted its core hydrogen fuel and swollen into a white supergiant.[1] Hohle and colleagues, using the parallax, extinction and analysis of spectrum, came up with a mass 14.95 ± 0.41 times that and luminosity 62,679 times that of the Sun.[2]
References
- 1 2 3 Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x.
- 1 2 3 Hohle, M. M.; Neuhäuser, R.; Schutz, B. F. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten 331 (4): 349, arXiv:1003.2335, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355
- ↑ Garrison, R. F. (December 1993), "Anchor Points for the MK System of Spectral Classification", Bulletin of the American Astronomical Society 25: 1319, Bibcode:1993AAS...183.1710G, retrieved 2012-02-04
External links
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