Alpha2 Capricorni
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Capricornus |
Right ascension | 20h 18m 03.25595s[1] |
Declination | −12° 32′ 41.4684″[1] |
Apparent magnitude (V) | +3.57[2] |
Characteristics | |
Spectral type | G8.5III-IV[3] |
U−B color index | +0.69[2] |
B−V color index | +0.94[2] |
Astrometry | |
Radial velocity (Rv) | −0.47±0.47[4] km/s |
Proper motion ( | RA: +62.63[1] mas/yr Dec.: +2.66[1] mas/yr |
Parallax ( | 31.9795 ± 0.3485 mas[5] |
Distance | 102 ± 1 ly (31.3 ± 0.3 pc) |
Absolute magnitude (MV) | +0.98+0.07 −0.06[6] |
Details[7] | |
Mass | 2.05±0.29 M☉ |
Radius | 8.38±0.58 R☉ |
Luminosity | 40.4±2.2 L☉ |
Surface gravity (log g) | 3.0[4] cgs |
Temperature | 5,030±160 K |
Metallicity [Fe/H] | −0.15±0.10 dex |
Rotational velocity (v sin i) | 2.7[4] km/s |
Age | 1.30±1.04 Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Alpha2 Capricorni (
Properties
The primary, component A, is an evolved G-type star with a stellar classification of G8.5III-IV,[3] indicating that the spectrum displays mixed traits of a giant and subgiant star. At the age of 1.3 billion years, is currently on the red giant branch[7] and is generating energy through hydrogen fusion along a shell surrounding an inert helium core. The star has around double the mass of the Sun and has expanded to more than eight times the Sun's radius. The star is radiating 40 times the solar luminosity from its photosphere at an effective temperature of 5,030 K.[7]
The secondary components B and C form a binary system that orbit each other with a period of about 244 years. Both stars have masses about half that of the Sun. They orbit the primary with an estimated period of around 1,500 years.[12] As of 2010, the pair lies at an angular separation of 6.6 arc seconds from the primary along a position angle of 196°.[13]
Nomenclature
In Chinese,
See also
References
- ^ a b c d van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
- ^ a b c d Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series, 34: 1–49, Bibcode:1978A&AS...34....1N.
- ^ a b Gray, R. O.; et al. (July 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, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637, S2CID 119476992.
- ^ a b c Massarotti, Alessandro; et al. (January 2008), "Rotational and radial velocities for a sample of 761 HIPPARCOS giants and the role of binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209.
- ^ 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.
- ^ Carney, Bruce W.; et al. (March 2008), "Rotation and Macroturbulence in Metal-Poor Field Red Giant and Red Horizontal Branch Stars", The Astronomical Journal, 135 (3): 892–906, arXiv:0711.4984, Bibcode:2008AJ....135..892C, doi:10.1088/0004-6256/135/3/892, S2CID 2756572.
- ^ a b c Reffert, Sabine; et al. (2015), "Precise radial velocities of giant stars. VII. Occurrence rate of giant extrasolar planets as a function of mass and metallicity", Astronomy and Astrophysics, 574A (2): 116–129, arXiv:1412.4634, Bibcode:2015A&A...574A.116R, doi:10.1051/0004-6361/201322360, hdl:10722/215277, S2CID 59334290.
- ^ "alf02 Cap -- Double or multiple star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-05-15.
- ^ Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.
- ^ a b Mamajek, Eric (February 1, 2017), IAU Catalog of Star Names, IAU Division C Working Group on Star Names (WGSN), retrieved 2017-05-17.
- ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ^ Tokovinin, A. (September 2008), "Comparative statistics and origin of triple and quadruple stars", Monthly Notices of the Royal Astronomical Society, 389 (2): 925–938, arXiv:0806.3263, Bibcode:2008MNRAS.389..925T, doi:10.1111/j.1365-2966.2008.13613.x, S2CID 16452670.
- ^ Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22
- ^ IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 22 May 2016.
- ^ (in Chinese)
中國 星座 神話 , written by陳 久金 . Published by台灣 書房 出版 有限 公司 , 2005, ISBN 978-986-7332-25-7. - ^ (in Chinese)
香港 太 空 館 -研究 資源 -亮 星 中 英 對照 表 Archived 2008-10-25 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
External links
- Kaler, James B., "Algedi", Stars, University of Illinois, retrieved 2017-05-17.
- Articles with Chinese-language sources (zh)
- Webarchive template wayback links
- Articles with short description
- Short description matches Wikidata
- Articles containing Chinese-language text
- Bayer objects
- G-type giants
- Capricornus
- Durchmusterung objects
- Flamsteed objects
- Henry Draper Catalogue objects
- Hipparcos objects
- Bright Star Catalogue objects
- Triple star systems
- Stars with proper names