Star in the constellation Capricornus
Upsilon Capricorni
Location of υ Capricorni (circled)
Observation dataEpoch J2000.0 Equinox J2000.0 (ICRS )
Constellation
Capricornus
Right ascension
20h 40m 02.94518s [ 1]
Declination
−18° 08′ 19.1664″[ 1]
Apparent magnitude (V)
5.17[ 2]
Characteristics
Spectral type
M1 III[ 3]
B−V color index
+1.65[ 2]
Astrometry Radial velocity (Rv ) −12.3± 1.6[ 4] km/s Proper motion (μ) RA: −22.764 mas /yr [ 5] Dec.: −22.170 mas /yr [ 5] Parallax (π)5.1719± 0.1354 mas [ 5] Distance 630 ± 20 ly (193 ± 5 pc ) Absolute magnitude (MV )−1.09[ 6]
Details Radius 92± 4[ 7] R ☉ Luminosity 1,283.0± 76.5[ 1] L ☉ Temperature 3,953+427 −193 [ 1] K Metallicity [Fe/H] −0.08[ 6] dex
Other designations υ Cap , 15 Capricorni , NSV 25208 , BD −18°5738 , FK5 773 , HD 196777 , HIP 101984 , HR 7900 , SAO 163779[ 8]
Database references SIMBAD data
Upsilon Capricorni , Latinized from υ Capricorni, is a solitary[ 9] star in the southern constellation of Capricornus . It has a reddish hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.17.[ 2] The star is about 630 light years away based on parallax ,[ 5] but is drifting closer with a radial velocity of −12 km/s.[ 4] It is 0.22 degree north of the ecliptic , so is subject to lunar occultations .[ 10] [ 11]
This is an aging red giant star on the asymptotic giant branch [ 12] with a stellar classification of M1 III,[ 3] 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 [ 7] and is radiating 1,283 times the luminosity of the Sun [ 1] from its swollen photosphere at an effective temperature of 3,953 K.[ 1]
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]
^ a b c d e f 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 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, Bibcode :1978MNRAS.183..285B , doi :10.1093/mnras/183.3.285 .
^ a b Houk, N.; Smith-Moore, M. (1988), Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars , vol. 4, Bibcode :1988mcts.book.....H .
^ a b Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters , 32 (11): 759– 771, arXiv :1606.08053 , Bibcode :2006AstL...32..759G , doi :10.1134/S1063773706110065 , S2CID 119231169 .
^ a b c Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties" . Astronomy and Astrophysics . 674 : A1. arXiv :2208.00211 . Bibcode :2023A&A...674A...1G . doi :10.1051/0004-6361/202243940 . S2CID 244398875 .
Gaia DR3 record for this source at VizieR .
^ a b 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 Baines, Ellyn K.; Clark, James H.; Kingsley, Bradley I.; Schmitt, Henrique R.; Stone, Jordan M. (2025-05-07), "Vintage NPOI: New and Updated Angular Diameters for 145 Stars", The Astronomical Journal , 169 (6): 293, arXiv :2506.02912 , Bibcode :2025AJ....169..293B , doi :10.3847/1538-3881/adc930 , ISSN 1538-3881
^ "* ups Cap" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2017-05-12 .
^ 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 .
^ White, Nathaniel M.; Feierman, Barry H. (September 1987), "A Catalog of Stellar Angular Diameters Measured by Lunar Occultation", Astronomical Journal , 94 : 751, Bibcode :1987AJ.....94..751W , doi :10.1086/114513 .
^ Dunham, D. W.; Evans, D. S.; Silverberg, E. C.; Wiant, J. R. (March 1973), "The angular diameter of Upsilon Capricorni and an occultation of SAO 118655.", Astronomical Journal , 78 : 199– 201, Bibcode :1973AJ.....78..199D , doi :10.1086/111398 .
^ Eggen, Olin J. (July 1992), "Asymptotic giant branch stars near the sun", Astronomical Journal , 104 (1): 275– 313, Bibcode :1992AJ....104..275E , doi :10.1086/116239 .
^ Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports , 5.1, 61 (1): 80– 88, Bibcode :2017ARep...61...80S , doi :10.1134/S1063772917010085 , S2CID 125853869 .