Xi2 Centauri

For other star systems with this Bayer designation, see Xi Centauri.
ξ2 Centauri
Location of ξ2 Centauri (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Centaurus
Right ascension 13h 06m 54.63940s[1]
Declination −49° 54′ 22.4823″[1]
Apparent magnitude (V) 4.30[2] + 9.38[3]
Characteristics
Spectral type B1.5 V[4] or B2 IV[5] + F7 V[3]
U−B color index −0.810[2]
B−V color index −0.197[2]
Astrometry
Radial velocity (Rv)+14.3±4.1[6] km/s
Proper motion (μ) RA: −26.15[1] mas/yr
Dec.: −12.03[1] mas/yr
Parallax (π)6.98 ± 0.24 mas[1]
Distance470 ± 20 ly
(143 ± 5 pc)
Absolute magnitude (MV)−1.51[7]
Orbit[8]
Period (P)7.6497 d
Eccentricity (e)0.35
Periastron epoch (T)2418077.493 JD
Argument of periastron (ω)
(secondary)		308.6°
Semi-amplitude (K1)
(primary)		38.8 km/s
Details
ξ2 Cen A
Mass8.1±0.1[4] M☉
Luminosity (bolometric)1,702[9] L☉
Surface gravity (log g)4.11±0.03[9] cgs
Temperature20,790±335[9] K
Rotational velocity (v sin i)25[10] km/s
Age11.5±3.7[4] Myr
ξ2 Cen B
Mass1.25[9] M☉
Luminosity2.4[9] L☉
Temperature6,194[9] K
Other designations
ξ2 Cen, CD−49° 7644, FK5 489, HD 113791, HIP 64004, HR 4942, SAO 223909.[11]
Database references
SIMBADdata

Xi2 Centauri, Latinized from ξ2 Centauri, is a triple star[12] system in the southern constellation of Centaurus. It is visible to the naked eye with an apparent visual magnitude of 4.30,[2] and forms a wide optical double with the slightly dimmer ξ1 Centauri.[13] Based upon an annual parallax shift of 6.98 mas, Xi2 Centauri lies roughly 470 light years from the Sun. At that distance, the visual magnitude is diminished by an interstellar extinction factor of 0.32 due to intervening dust.[14]

This system was discovered to be a single-lined spectroscopic binary in 1910 by American astronomer Joseph Haines Moore.[15][16] The pair, component A, orbit each other with a period of 7.6497 days and an eccentricity of 0.35.[8] The primary is a B-type star with a stellar classification of B1.5 V[4] or B2 IV,[5] depending on the source. This indicates it may be a main sequence star or a more evolved subgiant star. It has about 8.1[4] times the mass of the Sun and radiates 1,702 times the solar luminosity from its outer atmosphere at an effective temperature of 20,790 K.[9] It is a hybrid pulsator and shows spacings in both g and p modes.[17]

A third star, component B, is a magnitude 9.38 F-type main sequence star with a classification of F7 V. It has 1.25[9] times the mass of the Sun and radiates 2.4[9] times the solar luminosity at an effective temperature of 6,194[9] K. It lies at an angular separation of 25.1 arc seconds from the inner pair.[3] They share a common proper motion, indicating they may be gravitationally bound with an orbital period of around 41,000 years.[18]

The system has a peculiar velocity of 16.2±4.2 km/s.[6] It belongs to the Scorpius–Centaurus association and appears to be a member of the Gould's Belt.[19]

  1. ^ a b c d e 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 apjs15_459 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference Gahm1983 was invoked but never defined (see the help page).
  4. ^ a b c d e Cite error: The named reference Tetzlaff2011 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Hohle2010 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Bobylev2013 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Pourbaix2004 was invoked but never defined (see the help page).
  9. ^ a b c d e f g h i j Cite error: The named reference Gerbaldi2001 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Wolff2007 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference FogCity2003 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Gontcharov2012 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Moore1910 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Meubauer1931 was invoked but never defined (see the help page).
  17. ^ Sharma, Awshesh N.; Bedding, Timothy R.; Saio, Hideyuki; White, Timothy R. (2022). "Pulsating B stars in the Scorpius–Centaurus Association with TESS". Monthly Notices of the Royal Astronomical Society. 515 (1): 828–840. arXiv:2203.02582. Bibcode:2022MNRAS.515..828S. doi:10.1093/mnras/stac1816.
  18. ^ Cite error: The named reference Tokovinin2008 was invoked but never defined (see the help page).
  19. ^ Cite error: The named reference Bobylev2007 was invoked but never defined (see the help page).