Astronomy:Beta Circini
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Circinus[1] |
| Right ascension | 15h 17m 30.84945s[2] |
| Declination | −58° 48′ 04.3453″[2] |
| Apparent magnitude (V) | 4.07[1] |
| Characteristics | |
| Spectral type | A3 Va[3] |
| U−B color index | +0.09[4] |
| B−V color index | +0.088±0.007[1] |
| Astrometry | |
| Radial velocity (Rv) | 9.6±2[5] km/s |
| Proper motion (μ) | RA: −97.182[2] mas/yr Dec.: −136.055[2] mas/yr |
| Parallax (π) | 35.8205 ± 0.2515[2] mas |
| Distance | 91.1 ± 0.6 ly (27.9 ± 0.2 pc) |
| Absolute magnitude (MV) | +1.64[1] |
| Details | |
| Mass | 1.96+0.03 −0.01[6] M☉ |
| Radius | 1.92[7] R☉ |
| Luminosity | 19[1] L☉ |
| Surface gravity (log g) | 4.281[8] cgs |
| Temperature | 8676±33[6] K |
| Metallicity [Fe/H] | 0.16[1] dex |
| Rotational velocity (v sin i) | 59[4] km/s |
| Age | 370–500[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Beta Circini is the second-brightest star in the constellation of Circinus. Its name is a Bayer designation that is Latinized from β Circini, and abbreviated Beta Cir or β Cir. The star has an apparent visual magnitude of approximately 4.07,[1] which is bright enough to be viewed with the naked eye. Based upon an annual parallax shift of 35.8 mas as seen from the Earth, it is located at a distance of 91.1 light-years (27.9 pc) from the Sun.
With a stellar classification of A3 Va,[3] this is an A-type main-sequence star fusing atoms of hydrogen into helium at its core. It is between 370 and 500 million years old[6] and is spinning with a projected rotational velocity of 59 km/s.[4] The star has 1.96[6] times the mass of the Sun and around 1.9[7] times the Sun's radius. The star is radiating 19[1] times the Sun's luminosity from its photosphere at an effective temperature of 8,676 K.[6] 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).[6]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 58.7±7.3 MJ | 6,656 | — | — | — | — |
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 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.
- ↑ 2.0 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.
- ↑ 3.0 3.1 Gray, R. O. (2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal 132 (1): 161–170. doi:10.1086/504637. Bibcode: 2006AJ....132..161G.
- ↑ 4.0 4.1 4.2 Hoffleit, D.; Warren, Jr., W. H.. "HR 5670, database entry". The Bright Star Catalogue. CDS. ID V/50. http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=V/50/catalog&recno=5670.
- ↑ Evans, D. S (1967). "The Revision of the General Catalogue of Radial Velocities". Determination of Radial Velocities and Their Applications 30: 57. Bibcode: 1967IAUS...30...57E.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 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. doi:10.1093/mnras/stv2290. Bibcode: 2015MNRAS.454.4476S. https://academic.oup.com/mnras/article/454/4/4476/1003701.
- ↑ 7.0 7.1 Cotten, Tara H.; Song, Inseok (2016-07-01). "A Comprehensive Census of Nearby Infrared Excess Stars". The Astrophysical Journal Supplement Series 225 (1): 15. doi:10.3847/0067-0049/225/1/15. ISSN 0067-0049. Bibcode: 2016ApJS..225...15C. 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. doi:10.1086/318269. Bibcode: 2001ApJ...546..352S.
- ↑ "* bet Cir". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+bet+Cir.
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