HD 21389
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Camelopardalis |
| Right ascension | 03h 29m 54.74413s[1] |
| Declination | +58° 52′ 43.4995″[1] |
| Apparent magnitude (V) | 4.54[2] |
| Characteristics | |
| Spectral type | A0 Iae[2] |
| U−B color index | −0.11[3] |
| B−V color index | +0.56[3] |
| Variable type | α Cyg[4] |
| Astrometry | |
| Radial velocity (Rv) | −6.20[5] km/s |
| Proper motion (μ) | RA: 1.79[1] mas/yr Dec.: −1.09[1] mas/yr |
| Parallax (π) | 1.30 ± 0.56 mas[1] |
| Distance | 975[3] pc |
| Absolute magnitude (MV) | −7.20[3] |
| Details[2] | |
| Mass | 19.3 M☉ |
| Radius | 97 R☉ |
| Luminosity | 55,000 L☉ |
| Surface gravity (log g) | 1.75 cgs |
| Temperature | 9,730 K |
| Rotation | 25 |
| Age | 11[3] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Data sources: | |
| Hipparcos Catalogue, CCDM (2002), Bright Star Catalogue (5th rev. ed.) | |
HD 21389 is a supergiant variable star in reflection nebula VdB 15, in the constellation Camelopardalis. It is part of the Camelopardalis OB1 association. The near-identical member CS Camelopardalis lies half a degree to the north.
Since 1943, the spectrum of CE Cam has served as one of the stable anchor points by which other stars are classified.[6]
CE Camelopardalis is some 19 times as massive as the Sun and 55,000 timers as luminous. 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.[7]
CE Cam is embedded in a large dusty molecular cloud, part of which it illuminates as a reflection nebula (vdB15 or BFS 29). This is a region of ongoing star formation with stars aged from one to a hundred million years old. CE Cam itself is thought to be around 11 million years old, long enough to have exhausted its core hydrogen and evolved away from the main sequence into a supergiant.[3]
References
- ^ a b c d e Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
- ^ a b c Shultz, M.; Wade, G. A.; Petit, V.; Grunhut, J.; Neiner, C.; Hanes, D.; MiMeS Collaboration (2014). "An observational evaluation of magnetic confinement in the winds of BA supergiants". Monthly Notices of the Royal Astronomical Society. 438 (2): 1114. arXiv:1311.5116. Bibcode:2014MNRAS.438.1114S. doi:10.1093/mnras/stt2260.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ a b c d e f Lyder, David A. (2001). "The Stars in Camelopardalis OB1: Their Distance and Evolutionary History". The Astronomical Journal. 122 (5): 2634. Bibcode:2001AJ....122.2634L. doi:10.1086/323705.
- ^ Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
- ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065.
- ^ 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
- ^ 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
