Sigma Ceti

Sigma Ceti
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cetus
Right ascension 02h 32m 05.22884s[1]
Declination −15° 14′ 40.8278″[1]
Apparent magnitude (V) 4.78[2]
Characteristics
Spectral type F5 V[3] or F4 IV[4]
U−B color index −0.03[2]
B−V color index +0.45[2]
Astrometry
Radial velocity (Rv)−27.5±0.9[5] km/s
Proper motion (μ) RA: −80.21[1] mas/yr
Dec.: −146.29[1] mas/yr
Parallax (π)37.46 ± 0.25 mas[1]
Distance87.1 ± 0.6 ly
(26.7 ± 0.2 pc)
Absolute magnitude (MV)+2.68[3]
Details
σ Cet A
Mass1.21[6] M☉
Radius1.5[7] R☉
Luminosity7.6[8] L☉
Surface gravity (log g)4.07±0.07[9] cgs
Temperature6,527±59[9] K
Metallicity [Fe/H]−0.12±0.04[9] dex
Rotational velocity (v sin i)20[3] km/s
Age2.135[6] Gyr
Other designations
σ Cet, 76 Cet, BD−15° 449, FK5 1071, HD 15798, HIP 11783, HR 740, SAO 148445.[10]
Database references
SIMBADdata

Sigma Ceti (σ Ceti) is the Bayer designation for a star in the equatorial constellation of Cetus. With an apparent visual magnitude of 4.78,[2] it can be seen with the naked eye on a dark night. Based upon an annual parallax shift of 37.46 mas,[1] it lies at an estimated distance of 87.1 light years from the Sun. It is a probable astrometric binary star system.[11]

The primary, component A, appears to be a normal F-type main sequence star with a stellar classification of F5 V.[3] However, Malaroda (1975) assigned it a classification of F4 IV,[4] which would suggest it is a more evolved subgiant star. It is estimated to have 121%[6] of the Sun's mass and around 150% of the radius of the Sun.[7] With an age of about 2.1[6] billion years, it is radiating 7.6[8] times the solar luminosity from its outer atmosphere at an effective temperature of 6,527 K.[9]

  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 Mermilliod1986 was invoked but never defined (see the help page).
  3. ^ a b c d Cite error: The named reference Takeda2005 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Malaroda1975 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference deBruijne2012 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 aaa367_521 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. ^ a b c d Cite error: The named reference Prugniel2011 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).