Zeta Circini

ζ Circini
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Circinus
Right ascension 14h 54m 42.58159s[1]
Declination −65° 59′ 27.9460″[1]
Apparent magnitude (V) 6.08[2]
Characteristics
Spectral type B2/3 Vn[3]
U−B color index −0.617[2]
B−V color index −0.073[2]
Variable type SPB[4]
Astrometry
Radial velocity (Rv)−18.0±4.3[5] km/s
Proper motion (μ) RA: −6.40[1] mas/yr
Dec.: −12.56[1] mas/yr
Parallax (π)2.56 ± 0.36 mas[1]
Distanceapprox. 1,300 ly
(approx. 390 pc)
Absolute magnitude (MV)−1.82[6]
Details[4]
Mass5.5±1.0 M☉
Radius3.8±1.3 R☉
Luminosity602[7] L☉
Surface gravity (log g)4.03±0.20 cgs
Temperature16,788 K
Rotational velocity (v sin i)264±8 km/s
Age31.6±5.7[8] Myr
Other designations
ζ Cir, CD−65° 1813, HD 131058, HIP 72965, HR 5539, SAO 252951.[9]
Database references
SIMBADdata

Zeta Circini, Latinized from ζ Circini, is the Bayer designation for a star located in the southern constellation of Circinus. With an apparent visual magnitude of 6.08,[2] it is barely visible to the naked eye on a dark night. (According to the Bortle scale, it requires the lighting level of suburban skies or darker to be seen.) The distance to this star, as estimated using an annual parallax shift of 2.56 mas,[1] is around 1,300 light years.

This is a B-type main sequence star with a stellar classification of B2/3 Vn,[3] where the 'n' suffix indicates broad ("nebulous") absorption lines due to rotation. It is a slowly pulsating B star[4] with a frequency of 0.26877 d−1 and an amplitude of 0.0046 magnitude.[10] The averaged quadratic field strength of the star's longitudinal magnetic field is (1.06±0.46)×10−2 T.[11]

The star is around 32[8] million years old and is spinning rapidly with a projected rotational velocity of 264 km/s.[4] It has an estimated 5.5 times the mass of the Sun and 3.8 times the Sun's radius.[4] Zeta Circini radiates around 602[7] times the solar luminosity from its outer atmosphere at an effective temperature of 16,788 K.[4]

  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 GutierrezMoreno1968 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference houk1979 was invoked but never defined (see the help page).
  4. ^ a b c d e f Cite error: The named reference Hubrig2006 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. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Mcdonald2012 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Tetzlaff2011 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 Koen2002 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Bychkov2009 was invoked but never defined (see the help page).