Gamma Capricorni

From Wikipedia, the free encyclopedia
Jump to: navigation, search

Coordinates: Sky map 21h 40m 05.5s, −16° 39′ 44″

γ Capricorni
Capricornus constellation map.png
Gamma Capricorni is at left center.
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Capricornus
Right ascension 21h 40m 05.4563s[1]
Declination −16° 39′ 44.308″[1]
Apparent magnitude (V) +3.69
Characteristics
Spectral type A7mp[2]
U−B color index +0.22[3]
B−V color index +0.32[3]
Astrometry
Radial velocity (Rv) −31.2[4] km/s
Proper motion (μ) RA: 187.39[1] mas/yr
Dec.: −22.33[1] mas/yr
Parallax (π) 23.48 ± 1.10[1] mas
Distance 139 ± 7 ly
(43 ± 2 pc)
Details
Surface gravity (log g) 3.95[5] cgs
Temperature 7,520[5] K
Metallicity \begin{smallmatrix}\left[\frac{Fe}{H}\right]\ =\ 0.5\end{smallmatrix}[5]
Rotational velocity (v sin i) 40[6] km/s
Other designations
Nashira, 40 Capricorni, HR 8278, HD 206088, NN 4209, BD−17°6340, FK5 812, HIP 106985, SAO 164560.[2]

Gamma Capricorni (γ Cap, γ Capricorni) is a giant star in the constellation Capricornus. It has the traditional name Nashira, which comes from the Arabic سعد ناشرة - sa'd nashirah for "the lucky one" or "bearer of good news".

In Chinese, 壘壁陣 (Lěi Bì Zhèn), meaning Line of Ramparts, refers to an asterism consisting of γ Capricorni, κ Capricorni, ε Capricorni, δ Capricorni, ι Aquarii, σ Aquarii, λ Aquarii, φ Aquarii, 27 Piscium, 29 Piscium, 33 Piscium and 30 Piscium.[7] Consequently, γ Capricorni itself is known as 壘壁陣三 (Lěi Bì Zhèn sān, English: the Third Star of Line of Ramparts.)[8]

Because it is near the ecliptic, γ Capricorni can be occulted by the Moon, and (rarely) by planets.

γ Capricorni is a blue-white A-type (A7III) giant star with a mean apparent magnitude of +3.69. It is approximately 139 light years from Earth. It is classified as an Alpha2 Canum Venaticorum type variable star and its brightness varies by 0.03 magnitudes.

Nashira as the name[edit]

Nashira (AK-85) is once of United States navy ship.

References[edit]

  1. ^ a b c d e Perryman, M. A. C. et al (July 1997). "The HIPPARCOS Catalogue". Astronomy & Astrophysics 323: L49–L52. Bibcode:1997A&A...323L..49P. 
  2. ^ a b "HD 206088 -- Variable Star of alpha2 CVn type". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2009-11-12. 
  3. ^ a b Johnson, H. L.; Iriarte, B.; Mitchell, R. I.; Wisniewskj, W. Z. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory 4 (99). Bibcode:1966CoLPL...4...99J. 
  4. ^ Wilson, Ralph Elmer (1953). General catalogue of stellar radial velocities. Carnegie Institution of Washington. Retrieved 2007-05-14. 
  5. ^ a b c Burkhart, C.; Coupry, M. F. (September 1991). "The A and Am-Fm stars. I - The abundances of Li, Al, Si, and Fe". Astronomy and Astrophysics 249 (1): 205−216. Bibcode:1991A&A...249..205B. 
  6. ^ Royer, F.; Grenier, S.; Baylac, M.-O.; Gómez, A. E.; Zorec, J. (October 2002). "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i". Astronomy and Astrophysics 393: 897–911. arXiv:astro-ph/0205255. Bibcode:2002A&A...393..897R. doi:10.1051/0004-6361:20020943. 
  7. ^ (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.
  8. ^ (Chinese) 香港太空館 - 研究資源 - 亮星中英對照表, Hong Kong Space Museum. Accessed on line November 23, 2010.