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.
  | |
| 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] |
| Distance | 93 ± 1 ly (28.4 ± 0.3 pc) |
| Absolute magnitude (MV) | +1.64[4] |
| Details | |
| Mass | 1.96+0.03 −0.01[5] M☉ |
| Radius | 1.92[6] R☉ |
| Luminosity | 19[4] L☉ |
| Surface gravity (log g) | 4.281[7] cgs |
| Temperature | 8676±33[5] K |
| Metallicity [Fe/H] | 0.16[4] dex |
| Rotational velocity (v sin i) | 59[3] km/s |
| Age | 370–500[5] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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
editBeta 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]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 58.7±7.3 MJ | 6,656 | — | — | — | — |
References
edit- ^ 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.
- ^ a b c d e f g h "* bet Cir". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved September 5, 2008.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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