Beta Circini

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
Mass1.96+0.03
−0.01[5] M☉
Radius1.92[6] R☉
Luminosity19[4] L☉
Surface gravity (log g)4.281[7] cgs
Temperature8676±33[5] K
Metallicity [Fe/H]0.16[4] dex
Rotational velocity (v sin i)59[3] km/s
Age370–500[5] 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 main-sequence star fusing atoms of hydrogen into helium at its core. It is between 370 and 500 million years old[5] with around 1.9[6] 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.[5] It has one known sub-stellar companion.

Substellar companion

Beta Circini b is a distant brown dwarf companion orbiting the host star at a distance of 6,656 AU. It was detected as a proper motion companion to Beta Circini in 2015 by L.C. Smith and collaborators. Using BHAC15 isochrones, its mass is estimated at 0.056 M☉, or 59 MJ. It has a stellar classification of L1 and a temperature of 2,084 K (1,811 °C).[5]

The β Circini planetary system[5]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b 58.7±7.3 MJ 6,656 — — — —

References

  1. ^ a b c d e 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. ^ a b c d e f g h "* bet Cir". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved September 5, 2008.
  3. ^ a b c 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. ^ a b c d 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. ^ a b c d e f g 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.
  6. ^ a b Cotten, Tara H.; Song, Inseok (2016-07-01). "A Comprehensive Census of Nearby Infrared Excess Stars". The Astrophysical Journal Supplement Series. 225 (1): 15. arXiv:1606.01134. Bibcode:2016ApJS..225...15C. doi:10.3847/0067-0049/225/1/15. ISSN 0067-0049. Beta Circini's database entry at VizieR.
  7. ^ 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