Theta Cancri

Theta Cancri
Location of θ Cancri (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cancer
Right ascension 08h 31m 35.73082s[1]
Declination +18° 05′ 39.9166″[1]
Apparent magnitude (V) +5.323[2]
Characteristics
Spectral type K5 III[3]
U−B color index +1.949[2]
B−V color index +1.565[2]
Astrometry
Radial velocity (Rv)+44.47±0.19[4] km/s
Proper motion (μ) RA: −60.438[1] mas/yr
Dec.: −57.331[1] mas/yr
Parallax (π)7.3204 ± 0.1826 mas[1]
Distance450 ± 10 ly
(137 ± 3 pc)
Absolute magnitude (MV)−0.19[5]
Details
Radius40.02+2.22
−2.35[1] R☉
Luminosity353.1±10.1[1] L☉
Temperature3,955+121
−105[1] K
Other designations
θ Cnc, 31 Cancri, BD+18° 1963, FK5 2667, HD 72094, HIP 41822, HR 3357, SAO 97881[6]
Database references
SIMBADdata

Theta Cancri, Latinised from θ Cancri, is a multiple star[7][3] system in the zodiac constellation of Cancer. It is visible to the naked eye as a dim point of light with an apparent visual magnitude of +5.32.[2] The system is located at a distance of approximately 450 light-years away from the Sun, based on parallax,[1] and is drifting further away with a radial velocity of +44 km/s.[4] Since it is near the ecliptic, it can be occulted by the Moon[8] and, very rarely, by planets.

The primary, designated component A, is K-type giant star with a stellar classification of K5 III,[3] having exhausted the supply of hydrogen at its core, then cooled and expanded. At present it has 40[1] times the girth of the Sun. It is radiating 353[1] times the luminosity of the Sun at an effective temperature of 3,955 K.[1]

In Chinese astronomy, Ghost (Chinese: 鬼宿; pinyin: Guǐ Xiù) refers to an asterism consisting of Theta Cancri, Eta Cancri, Gamma Cancri and Delta Cancri.[9] Theta Cancri is the first star of Ghost (Chinese: 鬼宿一; pinyin: Guǐ Xiù yī), as it is also the determinative star for that asterism.[10]

  1. ^ a b c d e f g h i j k l Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference sps1966 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Hartkopf1984 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference White1987 was invoked but never defined (see the help page).
  9. ^ 陳久金 (2005). Zhōngguó Xīngzuò Shénhuà 中國星座神話 [Chinese Constellation Mythology]. 台灣古籍出版有限公司. p. 394. ISBN 978-986-7332-25-7.
  10. ^ 陳久金 (2005). Zhōngguó Xīngzuò Shénhuà 中國星座神話 [Chinese Constellation Mythology]. 台灣古籍出版有限公司. p. 193. ISBN 978-986-7332-25-7.