Sirius

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Sirius A / B
Canis Major constellation map.svg
Cercle rouge 100%.svg

The poseetion o Sirius (circled).
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Canis Major
Pronunciation /ˈsɪriəs/[1]
Richt ascension 06h 45m 08.9173s[2][note 1]
Declination −16° 42′ 58.017″[2][note 1]
Apparent magnitude (V) −1.47 (A)[2] / 8.30 (B)[3]
Characteristics
Spectral teep A1V (A)[2] / DA2 (B)[3]
U−B colour index −0.05 (A)[4] / −1.04 (B)[3]
B−V colour index 0.01 (A)[2] / −0.03 (B)[3]
Astrometry
Radial velocity (Rv) −7.6[2] km/s
Proper motion (μ) RA: −546.05[2][note 1] mas/yr
Dec.: −1223.14[2][note 1] mas/yr
Parallax (π) 379.21 ± 1.58[2][5] mas
Distance 8.60 ± 0.04 ly
(2.64 ± 0.01 pc)
Absolute magnitude (MV) 1.42 (A)[note 2] / 11.18 (B)[3]
Orbit[6]
Companion α CMa B
Period (P) 50.090 ± 0.055 yr
Semimajor axis (a) 7.50 ± 0.04"
Eccentricity (e) 0.5923 ± 0.0019
Inclination (i) 136.53 ± 0.43°
Longitude o the node (Ω) 44.57 ± 0.44°
Periastron epoch (T) 1894.130 ± 0.015
Argument o periastron (ω)
(secondary)
147.27 ± 0.54°
Details
α CMa A
Mass 2.02[7] M
Radius 1.711[7] R
Luminosity 25.4[7] L
Surface gravity (log g) 4.33[8] cgs
Temperatur 9,940[8] K
Metallicity [Fe/H] 0.50[9] dex
Rotation 16 km/s[10]
Age 2–3 × 108[7] years
α CMa B
Mass 0.978[7] M
Radius 0.0084 ± 3%[11] R
Luminosity 0.026[note 3] L
Surface gravity (log g) 8.57[11] cgs
Temperatur 25,200[7] K
Ither designations
Seestem: Dug Starn, Aschere, Canicula, Al Shira, Sothis,[12] Alhabor,[13] Mrgavyadha, Lubdhaka,[14] Tenrōsei,[15] α Canis Majoris (α CMa), 9 Canis Majoris (9 CMa), HD 48915, HR 2491, BD −16°1591, GCTP 1577.00 A/B, GJ 244 A/B, LHS 219, ADS 5423, LTT 2638, HIP 32349.
B: EGGR 49, WD 0642-166.[2][16][17]

Sirius (/ˈsɪriəs/) is the brichtest starn (in fact, a starn seestem) in the Yird's nicht sky.

Notes[eedit | eedit soorce]

  1. 1.0 1.1 1.2 1.3 Astrometric data, mirrored bi SIMBAD frae the Hipparcos catalogue, pertains tae the center o mass o the Sirius seestem. See § 2.3.4, Volume 1, The Hipparcos and Tycho Catalogues, European Space Agency, 1997, and the entry for Sirius in the Hipparcos catalogue (CDS ID I/239.)
  2. For apparent magnitude m an parallax π, the absolute magnitude Mv o Sirius A is gien bi:
    See: Tayler, Roger John (1994). The Stars: Their Structure and Evolution. Cambridge University Press. p. 16. ISBN 0-521-45885-4. 
  3. Bolometric luminosity o Sirius B calculatit frae L=4πR2σTeff4. (This simplifies tae Ls=(Rs)^2*(Ts)^4, whaur Ls, Rs an Ts are Luminosity, Radius an Temperatur aw relative tae solar values) See: Tayler, Roger John (1994). The Stars: Their Structure and Evolution. Cambridge University Press. p. 16. ISBN 0-521-45885-4. 

References[eedit | eedit soorce]

  1. "Sirius". Dictionary.com Unabridged (v 1.1). Random House, Inc. Retrieved 6 Aprile 2008. 
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 "Sirius A". SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg. Retrieved 20 October 2007. 
  3. 3.0 3.1 3.2 3.3 3.4 McCook, G. P.; Sion, E. M. "Entry for WD 0642-166". A Catalogue of Spectroscopically Identified White Dwarfs (August 2006 version). CDS.  ID III/235A.)
  4. Hoffleit, D.; Warren, Jr., W. H. (1991). "Entry for HR 2491". Bright Star Catalogue, 5th Revised Ed. (Preliminary Version). CDS.  ID V/50.
  5. van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357 
  6. van den Bos, W. H. (1960). "The Orbit of Sirius". Journal des Observateurs. 43: 145–151. Bibcode:1960JO.....43..145V. 
  7. 7.0 7.1 7.2 7.3 7.4 7.5 Liebert, J.; Young, P. A.; Arnett, D.; Holberg, J. B.; Williams, K. A. (2005). "The Age and Progenitor Mass of Sirius B". The Astrophysical Journal. 630 (1): L69–L72. arXiv:astro-ph/0507523Freely accessible. Bibcode:2005ApJ...630L..69L. doi:10.1086/462419. 
  8. 8.0 8.1 Adelman, Saul J. (Julie 8–13, 2004). "The Physical Properties of normal A stars". Proceedings of the International Astronomical Union. Poprad, Slovakia: Cambridge University Press. pp. 1–11. Bibcode:2004IAUS..224....1A. 
  9. Qiu, H. M.; Zhao, G.; Chen, Y. Q.; Li, Z. W. (2001). "The Abundance Patterns of Sirius and Vega". The Astrophysical Journal. 548 (2): 953–965. Bibcode:2001ApJ...548..953Q. doi:10.1086/319000. 
  10. Royer, F.; Gerbaldi, M.; Faraggiana, R.; Gómez, A. E. (2002). "Rotational velocities of A-type stars. I. Measurement of v sin i in the southern hemisphere". Astronomy and Astrophysics. 381 (1): 105–121. arXiv:astro-ph/0110490Freely accessible. Bibcode:2002A&A...381..105R. doi:10.1051/0004-6361:20011422. 
  11. 11.0 11.1 Holberg, J. B.; Barstow, M. A.; Bruhweiler, F. C.; Cruise, A. M.; Penny, A. J. (1998). "Sirius B: A New, More Accurate View". The Astrophysical Journal. 497 (2): 935–942. Bibcode:1998ApJ...497..935H. doi:10.1086/305489. 
  12. Hinckley, Richard Allen (1899). Star-names and Their Meanings. New York: G. E. Stechert. pp. 117–25. 
  13. doi:10.1111/j.1749-6632.1987.tb37197.x
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  14. Singh, Nagendra Kumar (2002). Encyclopaedia of Hinduism, A Continuing Series. Anmol Publications PVT. LTD. p. 794. ISBN 81-7488-168-9. 
  15. Spahn, Mark; Hadamitzky, Wolfgang; Fujie-Winter, Kimiko (1996). The Kanji dictionary. Tuttle language library. Tuttle Publishing. p. 724. ISBN 0-8048-2058-9. 
  16. "Sirius B". SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg. Retrieved 23 October 2007. 
  17. van Altena, W. F.; Lee, J. T.; Hoffleit, E. D. (1995). The general catalogue of trigonometric parallaxes (4th ed.). Yale University Observatory.  (CDS) ID I/238A.

Coordinates: Sky map 06h 45m 08.9173s, −16° 42′ 58.017″