Theta Canis Majoris

Theta Canis Majoris
Location of θ Canis Majoris (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Canis Major
Right ascension 06h 54m 11.399s[1]
Declination −12° 02′ 19.061″[1]
Apparent magnitude (V) 4.08[2]
Characteristics
Evolutionary stage Red giant
Spectral type K4 III[2]
U−B color index +1.69[3]
B−V color index +1.43[3]
Astrometry
Radial velocity (Rv)+96.2±0.1[4] km/s
Proper motion (μ) RA: −136.454 mas/yr[1]
Dec.: −14.322 mas/yr[1]
Parallax (π)12.0676 ± 0.62 mas[1]
Distance270 ± 10 ly
(83 ± 4 pc)[1]
Absolute magnitude (MV)−0.36±0.15[5]
Details[4]
Mass0.95±0.03 M☉
Radius33.01±0.75[6] R☉
Luminosity304.9±7[6] L☉
Surface gravity (log g)1.67±0.08 cgs
Temperature4196±43[6] K
Metallicity [Fe/H]−0.52±0.04 dex
Rotational velocity (v sin i)2.72±0.40 km/s
Age10.41±1.31 Gyr
Other designations
θ CMa, 14 Canis Majoris, BD−11°1681, FK5 266, GC 9051, HD 50778, HIP 33160, HR 2574, SAO 152071[7]
Database references
SIMBADdata

Theta Canis Majoris (θ Canis Majoris) is a solitary,[8] orange-hued star near the northern edge[9] of the constellation Canis Major, forming the nose of the "dog".[10] The star is visible to the naked eye with an apparent visual magnitude of 4.08.[2] Based upon an annual parallax shift of 12.07 mas as seen from Earth,[1] it is located about 270 light years from the Sun. The star is moving away from Earth with a radial velocity of +96.2 km/s.[4]

This is a evolved K-type giant star with a stellar classification of K4 III.[2] Theta Canis Majoris is 5% less massive than the Sun,[4] but has expanded to 33 times the Sun's size.[6] This old star, around ten billion years old,[4] is over two times older than the Solar System.[11] It irradiates 305 times the Sun's luminosity from its expanded photosphere at an effective temperature of 4,200 K.[6] This temperature gives it the cool orange hue of a K-type star.[12]

  1. ^ a b c d e f Cite error: The named reference DR3 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Setaiwan2004 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  4. ^ a b c d e Cite error: The named reference Jofre2015 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference daSilva2006 was invoked but never defined (see the help page).
  6. ^ a b c d e Cite error: The named reference npoi was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Kaler2013 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Crossen2012 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SolarSystem was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference csiro was invoked but never defined (see the help page).