Theta Capricorni

Theta Capricorni
Location of θ Capricorni (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Capricornus
Right ascension 21h 05m 56.82783s[1]
Declination −17° 13′ 58.3021″[1]
Apparent magnitude (V) +4.07[2]
Characteristics
Spectral type A1 V[3]
U−B color index +0.01[2]
B−V color index −0.01[2]
Astrometry
Radial velocity (Rv)−10.9[4] km/s
Proper motion (μ) RA: +79.33[1] mas/yr
Dec.: −62.01[1] mas/yr
Parallax (π)20.11 ± 0.28 mas[1]
Distance162 ± 2 ly
(49.7 ± 0.7 pc)
Absolute magnitude (MV)+0.60[5]
Details[6]
Mass2.24 M☉
Radius2.7[7] R☉
Luminosity65[8] L☉
Surface gravity (log g)4.19±0.14 cgs
Temperature10,001±340 K
Metallicity [Fe/H]+0.26[5] dex
Rotational velocity (v sin i)104 km/s
Age152 Myr
Other designations
θ Cap, 23 Cap, BD−17° 6174, FK5 1552, HD 200761, HIP 104139, HR 8075, SAO 164132[9]
Database references
SIMBADdata

Theta Capricorni, Latinized from θ Capricorni, is a white-hued star in the southern constellation of Capricornus,[10] positioned 0.58° south of the ecliptic.[11] Sometimes, this star is called by the name Dorsum,[12] meaning the back (of the goat) in Latin. It can be seen with the naked eye, having an apparent visual magnitude of +4.07.[2] Based upon an annual parallax shift of 20.11 mas as seen from the Earth,[1] the star is about 162 light years from the Sun. It is drifting closer with a radial velocity of −11 km/s.[4]

This is an ordinary A-type main sequence star with a stellar classification of A1 V.[3] Radial velocity variations indicate it may be a binary star system,[13] but when the system was examined in the infrared, no companion was detected.[14] Theta Capricorni has an estimated 2.24[6] times the mass of the Sun and around 2.7[7] times the Sun's radius. It is 152 million years old and is spinning fairly rapidly with a projected rotational velocity of 104 km/s.[6] The star is radiating 65[8] times the solar luminosity from its photosphere at an effective temperature of around 10,000 K.[6]

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Cowley1969 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Wilson1953 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  6. ^ a b c d Cite error: The named reference David2015 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference PasinettiFracassini2001 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Mcdonald2012 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Kaler2008 was invoked but never defined (see the help page).
  11. ^ Pratt, John P. (February 10, 2016). "Zodiac Stars". John Pratt's Web Site. Retrieved 2021-06-21.
  12. ^ Cite error: The named reference Dorsum was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Lagrange2009 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Ehrenreich2010 was invoked but never defined (see the help page).