Astronomy:Rho Centauri

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Short description: Binary star system in the constellation Centaurus
Rho Centauri
Location of ρ Centauri (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Centaurus[1]
Right ascension  12h 11m 39.12805s[2]
Declination −52° 22′ 06.4067″[2]
Apparent magnitude (V) +3.97[1]
Characteristics
Evolutionary stage main sequence
Spectral type B3 V[3]
U−B color index −0.650[4]
B−V color index −0.156±0.008[1]
Astrometry
Radial velocity (Rv)+15.0±4.1[5] km/s
Proper motion (μ) RA: −43.741[2] mas/yr
Dec.: −11.771[2] mas/yr
Parallax (π)11.8348 ± 0.3746[2] mas
Distance276 ± 9 ly
(84 ± 3 pc)
Absolute magnitude (MV)−1.33[1]
Orbit[6]
PrimaryA
CompanionB
Period (P)3.626 yr
Semi-major axis (a)0.0440″
Eccentricity (e)0.619
Inclination (i)164°
Longitude of the node (Ω)225°
Periastron epoch (T)2019.237
Argument of periastron (ω)
(secondary)
54°
Details
A
Mass5.413[7] M☉
Radius3.8[8] R☉
Luminosity810.42[1] L☉
Surface gravity (log g)3.95[9] cgs
Temperature19,500[9] K
Rotational velocity (v sin i)147[10] km/s
Age23.7±1.4[11] Myr
B
Mass3.583[7] M☉
Other designations
Rho Cen, ρ Cen, CD−51°6455, HD 105937, HIP 59449, HR 4638, SAO 239737[12]
Database references
SIMBADdata

Rho Centauri is a binary star[13] system in the southern constellation of Centaurus. Its name is a Bayer designation that is Latinized from ρ Centauri, and abbreviated Rho Cen or ρ Cen. This star is visible to the naked eye as a blue-white hued point of light with a combined apparent visual magnitude of +3.97.[1] The system is located approximately 276 light years from the Sun based on parallax, and is drifting further away with a radial velocity of around +15 km/s.[5] It is a proper motion member of the Lower Centaurus–Crux sub-group in the Scorpius–Centaurus OB association, the nearest such association of co-moving massive stars to the Sun.[3]

The primary component of this system is a B-type main-sequence star with a stellar classification of B3 V.[3] It is about 24[11] million years old with a high rate of spin, showing a projected rotational velocity of 147 km/s.[10] It has 5.4[7] times the mass of the Sun and 3.8[8] times the Sun's radius. The star is radiating 810[1] times the luminosity of the Sun from its photosphere at an effective temperature of 19,500 K.[9]

The secondary companion is 1.1 magnitudes fainter than the primary, with a projected separation of 5.68 astronomical unit|AU along a position angle of 19.72°, as of 2013.[13] It revolves around the primary star in 3.6 years, on an ecccentric orbit.[6] The mass is estimated at 3.6 times that of the Sun, or 66% that of the primary.[7]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.  XHIP record for this object at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940.  Gaia DR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 3.2 de Geus, E. J. et al. (June 1989), "Physical parameters of stars in the Scorpio-Centaurus OB association", Astronomy and Astrophysics 216 (1–2): 44–61, Bibcode: 1989A&A...216...44D 
  4. ↑ Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A photometric investigation of the Scorpio-Centaurus association", Astrophysical Journal Supplement 15: 459, doi:10.1086/190168, Bibcode: 1968ApJS...15..459G. 
  5. ↑ 5.0 5.1 Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters 32 (11): 759–771, doi:10.1134/S1063773706110065, Bibcode: 2006AstL...32..759G. 
  6. ↑ 6.0 6.1 Mason, Brian D. et al. (October 2023), "Speckle Interferometry at SOAR in 2022", The Astronomical Journal 166 (4): 139, doi:10.3847/1538-3881/acedaf, Bibcode: 2023AJ....166..139M. 
  7. ↑ 7.0 7.1 7.2 7.3 Gratton, R. et al. (October 2023), "Multiples among B stars in the Scorpius-Centaurus association", Astronomy & Astrophysics 678: A93, doi:10.1051/0004-6361/202346806, Bibcode: 2023A&A...678A..93G.  Vizier catalog entry
  8. ↑ 8.0 8.1 Pasinetti Fracassini, L. E. et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics 367 (2): 521–524, doi:10.1051/0004-6361:20000451, Bibcode: 2001A&A...367..521P. 
  9. ↑ 9.0 9.1 9.2 Levenhagen, R. S.; Leister, N. V. (2006), "Spectroscopic analysis of southern B and Be stars", Monthly Notices of the Royal Astronomical Society 371 (1): 252–262, doi:10.1111/j.1365-2966.2006.10655.x, Bibcode: 2006MNRAS.371..252L. 
  10. ↑ 10.0 10.1 Uesugi, Akira; Fukuda, Ichiro (1970), "Catalogue of rotational velocities of the stars", Contributions from the Institute of Astrophysics and Kwasan Observatory (University of Kyoto), Bibcode: 1970crvs.book.....U. 
  11. ↑ 11.0 11.1 Tetzlaff, N. et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode: 2011MNRAS.410..190T 
  12. ↑ "rho Cen". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=rho+Cen. 
  13. ↑ 13.0 13.1 Rizzuto, A. C. et al. (December 2013), "Long-baseline interferometric multiplicity survey of the Sco-Cen OB association", Monthly Notices of the Royal Astronomical Society 436 (2): 1694–1707, doi:10.1093/mnras/stt1690, Bibcode: 2013MNRAS.436.1694R.