Eta Canis Majoris
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Canis Major |
Right ascension | 07h 24m 05.70228s[1] |
Declination | –29° 18′ 11.1798″[1] |
Apparent magnitude (V) | 2.450[2] |
Characteristics | |
Spectral type | B5 Ia[3] |
U−B color index | −0.708[2] |
B−V color index | −0.087[2] |
Variable type | |
Astrometry | |
Radial velocity (Rv) | 41.1[5] km/s |
Proper motion ( | RA: −4.14[1] mas/yr Dec.: 5.81[1] mas/yr |
Parallax ( | 1.64 ± 0.40 mas[1] |
Distance | approx. 2,000 ly (approx. 600 pc) |
Absolute magnitude (MV) | −7.0[6] |
Details | |
Mass | 18.19[7] M☉ |
Radius | 54[8] R☉ |
Luminosity | 135,000 - 174,000[8] L☉ |
Surface gravity (log g) | 2.00[8] cgs |
Temperature | 15,000 - 16,000[8] K |
Rotational velocity (v sin i) | 40[8] km/s |
Age | 8.3[9] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Eta Canis Majoris (
Nomenclature[edit]
The traditional name Aludra originates from the Arabic: العذراء al-adhraa, 'the virgin'. This star, along with Epsilon Canis Majoris (Adhara), Delta Canis Majoris (Wezen) and Omicron2 Canis Majoris (Thanih al Adzari), were Al 'Adhārā (العذاري), 'the Virgins'.[12] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[13] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[14] included a table of the first two batches of names approved by the WGSN; which included Aludra for this star.
In Chinese,
Properties[edit]
A blue-white supergiant, Eta CMa has been used as a standard for the spectral type of B5Ia.[18]
Eta CMa shines brightly in the skies in spite of a large distance from Earth due to being intrinsically many times brighter than the Sun. It has a luminosity over 100,000 times and a radius around 54 times that of the Sun. It has only been around a fraction of the time the Sun has, less than 10 million years, yet is already in the last stages of its life. It is still expanding and may become a red supergiant, or perhaps has already passed that phase, but in either case it will become a supernova within the next few million years.[citation needed]
Eta CMa is classified as an Alpha Cygni-type variable star and its brightness varies from magnitude +2.38 to +2.48 over a period of 4.7 days.[4][19]
Namesakes[edit]
Both USS Aludra (AF-55), an Alstede-class stores ship, and USS Aludra (AK-72), a Crater-class cargo ship, were U.S. Navy vessels named after the star.
References[edit]
- ^ a b c d e van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
- ^ a b c Alcaino, Gonzalo (June 1969), "The Globular Clusters NGC 2808 and NGC 1851", Astrophysical Journal, 156: 853, Bibcode:1969ApJ...156..853A, doi:10.1086/150019
- ^ Prinja, R. K.; Massa, D. L. (October 2010), "Signature of wide-spread clumping in B supergiant winds", Astronomy and Astrophysics, 521: L55, arXiv:1007.2744, Bibcode:2010A&A...521L..55P, doi:10.1051/0004-6361/201015252, S2CID 59151633
- ^ a b Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V.; Frolov, M. S.; Antipin, S. V.; Kireeva, N. N.; Pastukhova, E. N. (1999). "The 74th Special Name-list of Variable Stars". Information Bulletin on Variable Stars. 4659: 1. Bibcode:1999IBVS.4659....1K.
- ^ Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veröff. Astron. Rechen-Inst. Heidelb, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode:1999VeARI..35....1W
- ^ 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 (3): 601–605, Bibcode:1979MNRAS.189..601U, doi:10.1093/mnras/189.3.601
- ^ Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (2022). "Stellar and substellar companions from Gaia EDR3. Proper-motion anomaly and resolved common proper-motion pairs". Astronomy and Astrophysics. 657: 657. arXiv:2109.10912. Bibcode:2022A&A...657A...7K. doi:10.1051/0004-6361/202142146. S2CID 237605138.
- ^ a b c d e Haucke, M.; Cidale, L. S.; Venero, R. O. J.; Curé, M.; Kraus, M.; Kanaan, S.; Arcos, C. (2018). "Wind properties of variable B supergiants. Evidence of pulsations connected with mass-loss episodes". Astronomy and Astrophysics. 614. arXiv:1902.01341. Bibcode:2018A&A...614A..91H. doi:10.1051/0004-6361/201731678. S2CID 126150688.
- ^ Tetzlaff, N.; et al. (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. S2CID 118629873.
- ^ "I
AU Catalog of Star Names". Retrieved 28 July 2016. - ^ 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, archived from the original on 2019-06-25, retrieved 2012-02-04
- ^ Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York, NY: Dover Publications Inc, p. 130, ISBN 0-486-21079-0, retrieved 2010-12-12
- ^ "I
AU Working Group on Star Names (WGSN)". Retrieved 22 May 2016. - ^ "Bulletin of the I
AU Working Group on Star Names, No. 1" (PDF). Retrieved 28 July 2016. - ^
弧 矢 (Hú Shǐ) is westernized into Koo She. R.H. Allen had opinion that Koo She refers to the asterism including Delta Velorum and Omega Velorum. AEEA opinion is, Delta Velorum is member of天 社 (Tiān Shè), meaning Celestial Earth God's Temple asterism, and Omega Velorum is not member of any asterisms.天 社 (Tiān Shè) is westernized into Tseen She and R.H. Allen used the term Tseen She for Chinese name of Eta Carinae. See Richard Hinckley Allen: Star Names — Their Lore and Meaning: Argo Navis and (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy)天文 教育 資 訊網 2006年 7月 17日 Archived 2012-02-04 at the Wayback Machine. - ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy)
天文 教育 資 訊網 2006年 7月 17日 Archived 2012-02-04 at the Wayback Machine - ^ "Light Curve". Hipparcos ESA. ESA. Retrieved 12 August 2022.
- ^ Morgan, W. W.; Abt, Helmut A.; Tapscott, J. W. (1978). Revised MK Spectral Atlas for stars earlier than the sun. Yerkes Observatory, University of Chicago. Bibcode:1978rmsa.book.....M.
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: CS1 maint: location missing publisher (link) - ^ Watson, Christopher (3 May 2013). "Eta Canis Majoris". AAVSO Website. American Association of Variable Star Observers. Retrieved 5 February 2014.