Zeta Cassiopeiae
 ζ Cas is found just below α Cas |
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| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Cassiopeia |
| Right ascension | 00h 36m 58.28419s[1] |
| Declination | +53° 53′ 48.8673″[1] |
| Apparent magnitude (V) | 3.666[2] |
| Characteristics | |
| Spectral type | B2IV[3] |
| U−B color index | –0.89[4] |
| B−V color index | –0.19[4] |
| Variable type | SPB[5] |
| Astrometry | |
| Radial velocity (Rv) | 2.0[2] km/s |
| Proper motion (μ) | RA: 17.38[1] mas/yr Dec.: –9.86[1] mas/yr |
| Parallax (π) | 5.50 ± 0.16[1] mas |
| Distance | 590 ± 20 ly (182 ± 5 pc) |
| Absolute magnitude (MV) | –2.63 |
| Details | |
| Mass | 8.4[6] M☉ |
| Radius | 5.8[7] R☉ |
| Luminosity | 6,400[5] L☉ |
| Surface gravity (log g) | 3.92[8] |
| Temperature | 22,180[8] K |
| Metallicity [Fe/H] | –0.23[8] dex |
| Rotational velocity (v sin i) | 2.0[9] km/s |
| Age | 2.0×107[5] years |
| Other designations | |
| Database references | |
| SIMBAD | data |
Zeta Cassiopeiae (ζ Cas, ζ Cassiopeiae) is a star in the constellation Cassiopeia. It has a blue-white hue and is classified as a B-type subgiant with an apparent magnitude of +3.67. It is approximately 590 light years from Earth.[1]
ζ Cas is a member of an unusual group of variable stars known as "Slowing Pulsating B" (SPB) stars.[10] It shows a pulsation frequency of 0.64 per day (or once every 1.56 days) and displays a weak magnetic field with a strength of roughly 3.35 × 10–2 T, which varies with a period of 5.37 days.[11] This likely matches the rotation rate of the star, which, when combined with the low projected rotational velocity, indicates the star may be seen nearly pole-on. Zeta Cassiopeiae is a candidate magnetic Bp star that shows an overabundance of helium. The star contains a randomly oriented fossil magnetic field, which impacts the outflow of the stellar wind. Collisions between streams from this stellar wind creates a shock front, with cooling particles settling toward a co-rotating disk.[12]
[edit] Chinese name
In Chinese astronomy, Zeta Cassiopeiae is called 附路, Pinyin: Fùlù, meaning Auxiliary Road, because this star is marking itself and stand alone in Auxiliary Road asterism, Legs (mansion) (see : Chinese constellation).[13] 附路 (Fùlù) is westernized into Foo Loo, but the name Foo Loo was designated not only for Zeta Cassiopeiae, but also for η Cassiopeiae (Achird) by R.H. Allen, with the meaning is "a by-path" [14]
[edit] See also
- Lists of stars in the constellation Cassiopeiae
- Class B Stars
- Pulsating Variable Stars
[edit] References
- ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, Bibcode 2007A&A...474..653V, doi:10.1051/0004-6361:20078357
- ^ a b c "NSV 225 -- Pulsating variable Star", SIMBAD (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HR153, retrieved 2010-02-22
- ^ Morgan, W. W.; Keenan, P. C. (1973), "Spectral Classification", Annual Review of Astronomy and Astrophysics 11: 29, Bibcode 1973ARA&A..11...29M, doi:10.1146/annurev.aa.11.090173.000333
- ^ a b Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99), Bibcode 1966CoLPL...4...99J
- ^ a b c Kaler, James B. (Jim), ZETA CAS (Zeta Cassiopeiae), University of Illinois, http://stars.astro.illinois.edu/sow/zetacas.html, retrieved 2010-02-22
- ^ Venn, K. A.; Lambert, D. L.; Lemke, M. (March 1996), "The abundance of boron in evolved A- and B-type stars.", Astronomy and Astrophysics 307: 849–859, Bibcode 1996A&A...307..849V
- ^ Underhill, A. B. et al. (November 1979), "Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars", Monthly Notices of the Royal Astronomical Society 189: 601–605, Bibcode 1979MNRAS.189..601U
- ^ a b c Gies, Douglas R.; Lambert, David L. (March 1992), "Carbon, nitrogen, and oxygen abundances in early B-type stars", Astrophysical Journal, Part 1 387: 673–700, Bibcode 1992ApJ...387..673G, doi:10.1086/171116
- ^ Wielen, R. et al. (1999), Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions, Astronomisches Rechen-Institut Heidelberg, Bibcode 1999VeARI..35....1W
- ^ Neiner, C. et al. (2003), "Discovery of a magnetic field in the Slowly Pulsating B star zeta Cassiopeiae", Astronomy and Astrophysics 406 (3): 1019–1031, Bibcode 2003A&A...406.1019N, doi:10.1051/0004-6361:2003074
- ^ De Cat, P. (June 2007), "Observational Asteroseismology of slowly pulsating B stars", Communications in Astroseismology 150: 167–174, Bibcode 2007CoAst.150..167D, doi:10.1553/cia150s167
- ^ Smith, M. A.; Bohlender, D. A. (May 2007), "Variations of the ultraviolet resonance lines of the B2 IV-V star ζ Cassiopeiae", Astronomy and Astrophysics 466 (2): 675–682, Bibcode 2007A&A...466..675S, doi:10.1051/0004-6361:20066639
- ^ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 9 日
- ^ Richard Hinckley Allen: Star Names — Their Lore and Meaning: Cassiopeia
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