47 Capricorni
47 Capricorni is a variable star located around 1,170[1] light years from the Sun in the southern constellation Capricornus,[6] near the northern border with Aquarius. It has the variable star designation of AG Capricorni and a Bayer designation of c2 Capricorni;[7] 47 Capricorni is the Flamsteed designation. This object is visible to the naked eye as a dim, red-hued point of light with an apparent visual magnitude that varies between 5.90 and 6.14. The star is receding from the Earth with a heliocentric radial velocity of +20 km/s.[5]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Capricornus |
Right ascension | 21h 46m 16.26887s[1] |
Declination | −09° 16′ 33.3799″[1] |
Apparent magnitude (V) | 6.00[2] (5.90 - 6.14)[3] |
Characteristics | |
Evolutionary stage | giant |
Spectral type | M2III[4] |
B−V color index | 1.629±0.010[2] |
Variable type | SRb[3] |
Astrometry | |
Radial velocity (Rv) | +19.80±0.89[5] km/s |
Proper motion (μ) | RA: +18.731[1] mas/yr Dec.: +8.387[1] mas/yr |
Parallax (π) | 2.7933 ± 0.2052[1] mas |
Distance | 1,170 ± 90 ly (360 ± 30 pc) |
Absolute magnitude (MV) | −1.76[2] |
Details | |
Radius | 102+11 −10[1] R☉ |
Luminosity | 1,940±162[1] L☉ |
Temperature | 3,784+188 −186[1] K |
Other designations | |
Database references | |
SIMBAD | data |
This is an aging red giant star with a stellar classification of M2III.[4] It is a semiregular variable star of subtype SRb with a period of 30.592 days and a maximum brightness of 5.9 magnitude.[3] With the supply of hydrogen at its core exhausted, the star has expanded to around 102[1] times the Sun's radius. It is radiating 1,940[1] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 3,784 K.[1]
References
- 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.
- 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.
- Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. 1. Bibcode:2009yCat....102025S.
- Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
- Famaey, B.; et al. (2009). "Spectroscopic binaries among Hipparcos M giants,. I. Data, orbits, and intrinsic variations". Astronomy and Astrophysics. 498 (2): 627. arXiv:0901.0934. Bibcode:2009A&A...498..627F. doi:10.1051/0004-6361/200810698. S2CID 18739721.
- "47 Cap". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2014-05-12.
- Kostjuk, N. D. (2002). "HD 207005". HD-DM-GC-HR-HIP-Bayer-Flamsteed Cross Index. Institute of Astronomy of Russian Academy of Sciences; CDS. IV/27A