Upsilon Capricorni

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]

Upsilon Capricorni

Location of υ Capricorni (circled)
Observation data Epoch 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

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]