Theta Capricorni

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Star
θ Capricorni
θ Cap in the constellation "Capricorn"
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation Capricorn
Right ascension 21 h 5 m 56.83 s
declination -17 ° 13 ′ 58.3 ″
Apparent brightness 4.08 likes
Typing
B − V color index −0.01 
U − B color index 0.01 
R − I index −0.02 
Spectral class A1 V
Astrometry
Radial velocity (−10.9 ± 1.2) km / s
parallax (20.11 ± 0.28)  mas
distance (162 ± 2)  ly
(49.7 ± 0.7)  pc
Proper movement 
Rec. Share: (79.33 ± 0.39)  mas / a
Dec. portion: (−62.01 ± 0.24)  mas / a
Physical Properties
Dimensions 2.7  M ☉
radius 2.6  R ☉
Luminosity

65  L ☉

Effective temperature 10800  K
Metallicity [Fe / H] 0.2
Other names
and catalog entries
Bayer name θ Capricorni
Flamsteed name 23 Capricorni
Bonn survey BD −17 ° 6174
Bright Star Catalog HR 8075 [1]
Henry Draper Catalog HD 200761 [2]
Hipparcos catalog HIP 104139 [3]
SAO catalog SAO 164132 [4]
Tycho catalog TYC 6350-1499-1 [5]Template: Infobox star / maintenance / specification of the TYC catalog
2MASS catalog 2MASS 21055682-1713585 [6]
Other names FK5 1552

Theta Capricorni (θ Cap) is a star in the constellation Capricorn . It has an apparent magnitude of 4.1 mag and its distance is approximately 162 light years .

Theta Capricorni is a white main sequence star about 2.7 times the mass, 2.6 times the diameter and 65 times the luminosity of the sun . The star rotates unusually fast with a projected equatorial rotation speed v ∙ sin i of about 110 km / s.

Theta Capricorni is sometimes referred to with the proper name "Dorsum" (from Latin dorsum , "back"), as it can be found in this area of ​​the constellation of the Capricorn.

Scientific research

In a 2001 study based on Hipparcos data, no measurable variability of the star was found. This property, in conjunction with other factors, made it a candidate for further investigation in 2005-2008, in which changes in the rotational speed of a star should be derived as an indication of the presence of extrasolar planets . For Theta Capricorni, this resulted in the likely existence of a companion.

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: Michigan Catalog of HD stars, Vol.4 (Houk +, 1988)
  4. ↑ VizieR: General Catalog of Stellar Radial Velocities (Wilson, 1953)
  5. ^ VizieR: VAST Survey. A-type stars multiplicity (De Rosa +, 2014)
  6. ^ VizieR. Fundamental parameters of stars (Allende Prieto +, 1999)
  7. ↑ a b VizieR: Infrared excesses of Hipparcos stars (McDonald +, 2012)
  8. ↑ a b VizieR: PCA-based inversion of stellar parameters (Gebran +, 2016)
  9. ^ P. Moore, R. Rees: Patrick Moore's Data Book of Astronomy . Cambridge University Press, Cambridge 2011, ISBN 978-0-521-89935-2 , p. 397.
  10. ^ VizieR: Hipparcos variable stars (Adelman +, 2001)
  11. ↑ A.-M. Lagrange, M. Desort, F. Galland, S. Udry, M. Mayor: Extrasolar planets and brown dwarfs around A – F type stars - VI. High precision RV survey of early type dwarfs with HARPS. In: Astronomy & Astrophysics. Vol. 495, 2009, doi: 10.1051 / 0004-6361: 200810105 , pp. 335-352 ( PDF; 852 KB ).