Sigma Hydrae
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Hydra |
Right ascension | 08h 38m 45.43747s[1] |
Declination | +03° 20′ 29.1701″[1] |
Apparent magnitude (V) | 4.48[2] |
Characteristics | |
Spectral type | K2 III[3] |
U−B color index | +1.23[2] |
B−V color index | +1.21[2] |
Astrometry | |
Radial velocity (Rv) | 27.28±0.19[4] km/s |
Proper motion ( | RA: −19.48[1] mas/yr Dec.: −15.92[1] mas/yr |
Parallax ( | 8.75 ± 0.25 mas[1] |
Distance | 370 ± 10 ly (114 ± 3 pc) |
Absolute magnitude (MV) | −0.84[5] |
Details[6] | |
Mass | 3.07 M☉ |
Radius | 27.6[7] R☉ |
Luminosity | 295 L☉ |
Surface gravity (log g) | 2.21±0.13[8] cgs |
Temperature | 4,491±51 K |
Metallicity [Fe/H] | 0.13±0.06[8] dex |
Age | 430 Myr |
Other designations | |
Database references | |
SIMBAD | data |
Sigma Hydrae (
Nomenclature
[edit]It bore the traditional name Minchir, appearing as Minchir es-schudscha in Bode's large star atlas, Uranographia. The name which derived from the Arabic appelationمنخر الشجاع minkhar ash-shujāʽ "the nostril brave one" (the hydra) for this star. The name is erroneously[citation needed] spelt as Al Minliar al Shuja in the Yale Bright Star Catalogue.[12] In 2016, the I
This star, along with Delta Hydrae (Lisan al Shudja), Epsilon Hydrae, Zeta Hydrae, Eta Hydrae and Rho Hydrae, were Ulug Beg's Min al Azʽal, "Belonging to the Uninhabited Spot".[14] (According to a 1971 NASA memorandum, Min al Azʽal or Minazal were the title for five stars : Delta Hydrae as Minazal I, Eta Hydrae as Minazal II, Epsilon Hydrae as Minazal III, Rho Hydrae as Minazal IV and Zeta Hydrae as Minazal V.[15])
In Chinese,
The people of Groote Eylandt, used the name Unwala ("The Crab") for the star cluster including this star, Delta Hydrae (Lisan al Shudja), Epsilon Hydrae, Zeta Hydrae, Eta Hydrae and Rho Hydrae.[18]
Properties
[edit]This is an evolved K-type giant star with a stellar classification of K2 III.[3] The measured angular diameter of this star, after correction for limb darkening, is 2.25±0.03 mas.[19] At its estimated distance, this yields a physical size of about 27.6 times the radius of the Sun.[7] It has about three times the mass of the Sun and radiates 295 times the solar luminosity from its outer atmosphere at an effective temperature of 4,491 K. Sigma Hydrae is around 430 million years old.[6]
References
[edit]- ^ a b c d e f van Leeuwen, F. (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 d Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.
- ^ a b Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey, 5, Bibcode:1999MSS...C05....0H.
- ^ a b Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430 (1): 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272, S2CID 17804304
- ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ a b Luck, R. Earle (September 2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 23, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114, 88.
- ^ a b Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, vol. 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
- ^ a b Prugniel, Ph.; et al. (July 2011), "The atmospheric parameters and spectral interpolator for the MILES stars", Astronomy & Astrophysics, 531: A165, arXiv:1104.4952, Bibcode:2011A&A...531A.165P, doi:10.1051/0004-6361/201116769, S2CID 54940439.
- ^ "* sig Hya". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-01-08.
{{cite web}}
: CS1 maint: postscript (link) - ^ a b "Naming Stars". IAU.org. Retrieved 16 December 2017.
- ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ^ "VizieR Service".
- ^ "I
AU Working Group on Star Names (WGSN)". Retrieved 22 May 2016. - ^ Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York, NY: Dover Publications Inc. p. 249. ISBN 0-486-21079-0. Retrieved 2010-12-12.
- ^ Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars (PDF), Jet Propulsion Laboratory, California Institute of Technology, retrieved 2017-01-09.
- ^ (in Chinese)
中國 星座 神話 , written by陳 久金 . Published by台灣 書房 出版 有限 公司 , 2005, ISBN 978-986-7332-25-7. - ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy)
天文 教育 資 訊網 2006年 5月 28日 - ^ Selin, Helaine, ed. (1997), Encyclopaedia of the history of science, technology, and medicine in non-western cultures, Dordrecht: Kluwer Academic Publishers, p. 105, ISBN 9780792340669.
- ^ Richichi, A.; et al. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039.