World Library  
Flag as Inappropriate
Email this Article

Eta Centauri

Article Id: WHEBN0003117288
Reproduction Date:

Title: Eta Centauri  
Author: World Heritage Encyclopedia
Language: English
Subject: Zeta Centauri, Centaurus, Be stars, Nova Centauri 2013, GJ 3737
Publisher: World Heritage Encyclopedia

Eta Centauri

Eta Centauri
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Centaurus
Right ascension 14h 35m 30.42416s[1]
Declination −42° 09′ 28.1708″[1]
Apparent magnitude (V) +2.35[2] (2.30 - 2.41[3])
Spectral type B1.5 Vne[4]
U−B color index −0.862[2]
B−V color index −0.215[2]
Variable type γ Cassiopeiae[3]
Radial velocity (Rv) –0.2[5] km/s
Proper motion (μ) RA: −34.73[1] mas/yr
Dec.: −32.72[1] mas/yr
Parallax (π) 10.67 ± 0.21[1] mas
Distance 306 ± 6 ly
(94 ± 2 pc)
Mass 12.0 ± 0.3[6] M
Radius 5-6 R
Luminosity 8,700[4] L
Surface gravity (log g) 3.20[7] cgs
Temperature 25,700[4] K
Rotational velocity (v sin i) 330[4] km/s
Age 5.6 ± 1.0[6] Myr
Other designations
CD−41°8917, CP−41°6839, FK5 537, HD 127972, HIP 71352, HR 5440, SAO 225044.[8]
Database references

Eta Centauri (η Cen, η Centauri) is a star in the southern constellation of Centaurus. It has an apparent visual magnitude of +2.35[2] and is located at a distance of around 306 light-years (94 parsecs).[1] In traditional Chinese astronomy, Eta Centauri was known as 庫樓二[9] (meaning: the Second (Star) of Koo Low).[10]

The stellar classification of this star is B1.5 Vne,[4] indicating that it is a B-type main sequence star. The 'n' suffix means that the absorption lines are broadened from rapid rotation. It has a projected rotational velocity of 330 km s−1[4] and completes a full rotation in less than a day. This is a Be star as shown by the 'e' suffix,[11] which means it has variable emissions in its hydrogen spectral lines. This emission can be modeled by a decretion disk of gas that has been ejected from the star and now follows a near Keplerian orbit around the central body.[12] Finally it is slightly variable, and classified as a Gamma Cassiopeiae variable star with multiple periods of variability.[3]

Eta Centauri has about 12[6] times the mass of the Sun, placing it above the dividing line between stars that evolve into white dwarfs and those that turn into supernovae. It is radiating 8,700[4] times as much luminosity as the Sun from its outer atmosphere at an effective temperature of 25,700 K.[4] This heat causes the star to glow with the blue-white hue common to B-type stars.[13] Eta Centauri is a proper motion member of the Upper-Centaurus Lupus sub-group in the Scorpius-Centaurus OB association, the nearest such co-moving association of massive stars to the Sun.[7]

See also


  1. ^ a b c d e f
  2. ^ a b c d
  3. ^ a b c
  4. ^ a b c d e f g h
  5. ^
  6. ^ a b c
  7. ^ a b
  8. ^
  9. ^ (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.
  10. ^
  11. ^
  12. ^
  13. ^

External links

  • Eta Centauri by Jim Kaler.
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.