β Circini
Location of β Circini (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Circinus
Right ascension 15h 17m 30.8488s[1]
Declination −58° 48 04.3384[1]
Apparent magnitude (V) 4.069[2]
Characteristics
Spectral type A3 Va[2]
U−B color index +0.09[3]
B−V color index +0.09[3]
Astrometry
Radial velocity (Rv)9.6 ± 2[2] km/s
Proper motion (μ) RA: −96.742±0.491[1] mas/yr
Dec.: −136.541±0.621[1] mas/yr
Parallax (π)35.1736 ± 0.4253 mas[1]
Distance93 ± 1 ly
(28.4 ± 0.3 pc)
Absolute magnitude (MV)+1.64[4]
Details
Radius1.3[5] R
Luminosity19[4] L
Surface gravity (log g)4.281[6] cgs
Temperature8676±33[7] K
Metallicity [Fe/H]0.16[4] dex
Rotational velocity (v sin i)59[3] km/s
Age370–500[7] Myr
Other designations
β Cir, Beta Circini, Beta Cir, CPD−58 5875, FK5 561, GC 20526, GJ 580.1, GJ 9516, HD 135379, HIP 74824, HR 5670, PPM 343590, SAO 242384.[2]
Database references
SIMBADdata

Beta Circini, Latinized from β Circini, is an A-type main sequence star and is the second-brightest star in the constellation of Circinus.[2] It has an apparent visual magnitude of approximately 4.069,[2] which is bright enough to be viewed with the naked eye. Based upon an annual parallax shift of 35.17 mas as seen from the Earth,[2] it is located about 93 light years from the Sun.

With a stellar classification of A3 Va,[2] this is an A-type main-sequence star. It is between 370 and 500 million years old[7] with around 1.3[5] times the Sun's radius. The star is radiating 19[4] times the Sun's luminosity from its photosphere at an effective temperature of 8,676 K.[7] It has one known sub-stellar companion.

Planetary System

Beta Circini b is a distant brown dwarf companion orbiting the host star at a distance of 6,656 AU.[8][7] It has a surface temperature of 2,084.0 K. Its mass was estimated using the Spectrum method which concluded that the object has a mass of 56.0±7.0 MJ.[8]

The β Circini planetary system[8]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b 56.0 (± 7.0) MJ 6656.0

References

  1. 1 2 3 4 5 Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. 1 2 3 4 5 6 7 8 "* bet Cir". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved September 5, 2008.
  3. 1 2 3 HR 5670, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line September 5, 2008.
  4. 1 2 3 4 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  5. 1 2 HD 135379, database entry, Catalog of Apparent Diameters and Absolute Radii of Stars (CADARS), 3rd edition, L. E. Pasinetti-Fracassini, L. Pastori, S. Covino, and A. Pozzi, CDS ID II/224. Accessed on line September 5, 2008.
  6. Song, Inseok; et al. (February 2001), "Ages of A-Type Vega-like Stars from uvbyβ Photometry", The Astrophysical Journal, 546 (1): 352–357, arXiv:astro-ph/0010102, Bibcode:2001ApJ...546..352S, doi:10.1086/318269, S2CID 18154947
  7. 1 2 3 4 5 Smith, L. C.; et al. (2015). "Discovery of a brown dwarf companion to the A3V star β Circini". Monthly Notices of the Royal Astronomical Society. 454 (4): 4476–4483. arXiv:1509.09226. Bibcode:2015MNRAS.454.4476S. doi:10.1093/mnras/stv2290. hdl:2299/16835. S2CID 18570256.
  8. 1 2 3 "β Circini b". Extrasolar Planets Encyclopaedia. Retrieved October 30, 2015.
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