Astronomy:Upsilon Capricorni
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Capricornus[1] |
| Right ascension | 20h 40m 02.944s[2] |
| Declination | −18° 08′ 19.17″[3] |
| Apparent magnitude (V) | 5.17[4] |
| Characteristics | |
| Evolutionary stage | asymptotic giant branch[5] |
| Spectral type | M1 III[6] |
| B−V color index | +1.65[4] |
| Astrometry | |
| Radial velocity (Rv) | −12.3±1.6[7] km/s |
| Proper motion (μ) | RA: −22.764[2] mas/yr Dec.: −22.170[2] mas/yr |
| Parallax (π) | 5.1719 ± 0.1354[2] mas |
| Distance | 630 ± 20 ly (193 ± 5 pc) |
| Absolute magnitude (MV) | −1.09[1] |
| Details | |
| Radius | 92±4[8] R☉ |
| Luminosity | 1,283.0±76.5[3] L☉ |
| Temperature | 3,953+427 −193[3] K |
| Metallicity [Fe/H] | −0.08[1] dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
Upsilon Capricorni is a solitary,[10] reddish hued star in the southern constellation of Capricornus. Its name is a Bayer designation that is Latinized from υ Capricorni, and abbreviated Upsilon Cap or υ Cap. This star is dimly visible to the naked eye with an apparent visual magnitude of 5.17.[4] The star is about 630 light years away based on parallax,[2] but is drifting closer with a radial velocity of −12 km/s.[7] It is 0.22 degree north of the ecliptic, so is subject to lunar occultations.[11][12]
This is an aging red giant star on the asymptotic giant branch[5] with a stellar classification of M1 III,[6] a star that has exhausted the supply of hydrogen at its core then cooled and expanded. It has 92 times the radius of the Sun[8] and is radiating 1,283 times the luminosity of the Sun[3] from its swollen photosphere at an effective temperature of 3,953 K.[3]
It is a suspected variable star of unknown type with a brightness that has been measured ranging from a peak of 5.19 down to 5.24.[13]
References
- ↑ 1.0 1.1 1.2 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 3.2 3.3 3.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 4.0 4.1 4.2 Barnes, T. G. et al. (May 1978), "Stellar angular diameters and visual surface brightness. III - an improved definition of the relationship", Monthly Notices of the Royal Astronomical Society 183 (3): 285–304, doi:10.1093/mnras/183.3.285, Bibcode: 1978MNRAS.183..285B.
- ↑ 5.0 5.1 Eggen, Olin J. (July 1992), "Asymptotic giant branch stars near the sun", Astronomical Journal 104 (1): 275–313, doi:10.1086/116239, Bibcode: 1992AJ....104..275E.
- ↑ 6.0 6.1 Houk, N.; Smith-Moore, M. (1988), Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars, 4, Bibcode: 1988mcts.book.....H.
- ↑ 7.0 7.1 Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters 32 (11): 759–771, doi:10.1134/S1063773706110065, Bibcode: 2006AstL...32..759G.
- ↑ 8.0 8.1 Baines, Ellyn K. et al. (May 7, 2025), "Vintage NPOI: New and Updated Angular Diameters for 145 Stars" (in en), The Astronomical Journal 169 (6): 293, doi:10.3847/1538-3881/adc930, ISSN 1538-3881, Bibcode: 2025AJ....169..293B
- ↑ "* ups Cap". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+ups+Cap.
- ↑ 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ White, Nathaniel M.; Feierman, Barry H. (September 1987), "A Catalog of Stellar Angular Diameters Measured by Lunar Occultation", Astronomical Journal 94: 751, doi:10.1086/114513, Bibcode: 1987AJ.....94..751W.
- ↑ Dunham, D. W. et al. (March 1973), "The angular diameter of Upsilon Capricorni and an occultation of SAO 118655.", Astronomical Journal 78: 199–201, doi:10.1086/111398, Bibcode: 1973AJ.....78..199D.
- ↑ Samus, N. N. et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1 61 (1): 80–88, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S.
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