Nashira

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Star
Nashira (γ Capricorni)
γ cap in the constellation "Capricorn"
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation Capricorn
Right ascension 21 h 40 m 5.46 s
declination -16 ° 39 ′ 44.3 ″
Apparent brightness 3.77 likes
Typing
B − V color index 0.31 
U − B color index 0.21 
R − I index 0.13 
Spectral class Am (kF0 hF1 V mF2)
Variable star type α 2 CVn 
Astrometry
Radial velocity (−31.2 ± 0.5) km / s
parallax (20.77 ± 0.72)  mas
distance (157 ± 6)  ly
(48.1 ± 1.7)  pc
Proper movement 
Rec. Share: (187.56 ± 0.78)  mas / a
Dec. portion: (−22.45 ± 0.47)  mas / a
Physical Properties
Dimensions 2.25  M ☉
radius 4.3  R ☉
Effective temperature 7240  K
Other names
and catalog entries
Bayer name γ Capricorni
Flamsteed name 40 capricorni
Bonn survey BD −17 ° 6340
Bright Star Catalog HR 8278 [1]
Henry Draper Catalog HD 206088 [2]
Gliese catalog FY 4209 [3]
Hipparcos catalog HIP 106985 [4]
SAO catalog SAO 164560 [5]
Tycho catalog TYC 6362-1078-1 [6]
2MASS catalog 2MASS 21400544-1639443 [7]
Other names FK5 812

Nashira is the proper name of the star Gamma Capricorni (γ Cap) in the constellation Capricorn . Nashira has an apparent magnitude of 3.8 mag and is approximately 157 light years away.

It is a white-yellow main sequence star with over 2 times the mass, over 4 times the diameter and 60 times the luminosity of the sun . Its surface temperature is around 7200 K.

Nashira belongs to a group of variable stars , the Alpha-2-Canum Venaticorum variables, whose characteristic feature is magnetic field fluctuations. Nashira also shows slight fluctuations in brightness with an amplitude of 0.03 mag.

The name Nashira is derived from the old Arabic name سعد ناشرة / saʿd nāšira  / 'spreading happiness' for the star couple Gamma and Delta Capricorni. Of the Working Group on Star Names (WGSN) of the IAU for the standardization of star names was in 2016 officially awarded the proper name Nashira in "IAU Catalog of Star Names" for Gamma Capricorni.

Scientific research

The spectrum of the star shows peculiarities according to which it was classified as an abnormal metal line star (Am star). It shows metal lines like an F2 star, Balmer series hydrogen lines like an F1 V star, and calcium lines like an F0 star. As is typical for such stars, a relatively low value of 31 km / s was found for the projected equatorial rotation speed v ∙ sin i .

Individual evidence

  1. ^ A b c VizieR: Hipparcos, the New Reduction (van Leeuwen, 2007) - The Astrometric Catalog
  2. ↑ a b c VizieR: Stellar Photometry in Johnson's 11-color system (Ducati, 2002)
  3. ^ VizieR: Rotation and Spectral Peculiarities (Abt + 1995)
  4. ↑ VizieR: Pulkovo radial velocities for 35493 HIP stars (Gontcharov, 2006)
  5. ↑ a b c VizieR: Fundamental parameters of stars (Allende Prieto +, 1999)
  6. ↑ VizieR: AAVSO International Variable Star Index VSX (Watson +, 2006-2014)
  7. ^ D. Adams: The Scattering Auspice. Retrieved November 29, 2016 .
  8. ↑ Bulletin of the IAU Working Group on Star Names, No. 2. IAU Division C Education, Outreach and Heritage, 2016 ( PDF; 158 kB ).
  9. ^ HA Abt, NI Morrell: The relation between rotational velocities and spectral peculiarities among A-type stars. In: The Astrophysical Journal Supplement Series. Vol. 99, 1995, doi: 10.1086 / 192182 , pp. 135-172 ( bibcode : 1995ApJS ... 99..135A ).