Theta Antliae

θ Antliae
Location of θ Antliae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Antlia
Right ascension 09h 44m 12.09512s[1]
Declination –27° 46′ 10.1011″[1]
Apparent magnitude (V) 4.79[2]
Characteristics
Spectral type A8 Vm + G7 III[3]
U−B color index +0.35[2]
B−V color index +0.50[2]
Astrometry
Radial velocity (Rv)+24.0[4] km/s
Proper motion (μ) RA: –53.23[1] mas/yr
Dec.: +37.24[1] mas/yr
Parallax (π)7.5602 ± 0.8169 mas[5]
Distanceapprox. 430 ly
(approx. 130 pc)
Orbit[6]
Companionθ Ant B
Period (P)18.32 yr
Semi-major axis (a)0.134″
Eccentricity (e)0.445
Inclination (i)124°
Longitude of the node (Ω)176.8°
Periastron epoch (T)1965.75
Details[7]
θ Ant A
Mass1.8 ± 0.1 M☉
θ Ant B
Mass2.1 ± 0.5 M☉
Other designations
CD–27 6881, HIP 47758, FK5 366, HD 84367, HR 3871, SAO 177908, PPM 256646[8]
Database references
SIMBADdata

Theta Antliae (θ Ant, θ Antliae) is the Bayer designation for a binary star in the southern constellation of Antlia. The pair have a combined apparent visual magnitude of +4.78;[2] the brighter component is magnitude +5.30 while the secondary is +6.18.[9] Based upon parallax measurements, it is located at a distance of around 430 light-years (130 parsecs) from Earth.

The primary component of this system, θ Antliae A, has a stellar classification of A8 Vm,[3] indicating that it is an A-type main sequence star with enhanced metallic lines in its spectrum. The companion, θ Antliae B, is a giant star with a classification of G7 III.[3] The pair have an orbital period of 18.3 years, a significant eccentricity of 0.445, and they have an angular separation of 0.1 arcseconds.[6]

  1. ^ a b c d Cite error: The named reference aaa474_2_653 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference clpl4_99 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference apjss143_2_513 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference gcrv1953 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Gaia-DR2 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference aass47_569 was invoked but never defined (see the help page).
  7. ^ Docobo, J. A.; Andrade, M. (2012). "Dynamical and physical properties of 22 binaries discovered by W. S. Finsen". Monthly Notices of the Royal Astronomical Society. 428 (1): 321–339. Bibcode:2013MNRAS.428..321D. doi:10.1093/mnras/sts045.
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference mnras389_2_869 was invoked but never defined (see the help page).