Upsilon Boötis

Upsilon Boötis is a single,^[9] orange-hued star in the northern constellation of Boötes. Its name is a Bayer designation that is Latinized from υ Boötis, and abbreviated Upsilon Boo or υ Boo. This is a fourth^[2] magnitude star that is visible to the naked eye. Based upon an annual parallax shift of 12.38 mas as seen from the Earth,^[1] it is located about 243 light-years (75 pc) distant. The star is moving closer to the Sun with a radial velocity of −6 km/s.^[4]

Upsilon Boötis

Location of υ Boötis (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Boötes
Right ascension	13h 49m 28.641s[1]
Declination	+15° 47′ 52.46″[1]
Apparent magnitude (V)	4.023[2]
Characteristics
Spectral type	K5.5 III[3]
U−B color index	+1.893[2]
B−V color index	+1.518[2]
Astrometry
Radial velocity (Rv)	−5.94±0.26[4] km/s
Proper motion (μ)	RA: −93.269 mas/yr[1] Dec.: +40.166 mas/yr[1]
Parallax (π)	13.4228±0.1380 mas[1]
Distance	243 ± 2 ly (74.5 ± 0.8 pc)
Absolute bolometric magnitude (Mbol)	−1.44±0.14[5]
Details
Mass	1.11±0.33[6] M☉
Radius	40.72+0.77 −0.79[7] R☉
Luminosity	332±54[6] L☉
Surface gravity (log g)	1.5[4] cgs
Temperature	3,920[6] K
Metallicity [Fe/H]	−0.23[4] dex
Rotational velocity (v sin i)	5.1[4] km/s
Age	10.08±1.41[7] Gyr
Other designations
υ Boo, 5 Boötis, BD+16°2564, GC 18674, HD 120477, HIP 67459, HR 5200, SAO 100725, PPM 130100[8]
Database references
SIMBAD	data

This is an evolved K-type giant star with a stellar classification of K5.5 III.^[3] Astroseismology was used to obtain a mass estimate of 1.11 times the mass of the Sun,^[6] while interferometric measurements give a size of about 38^[5] times the Sun's radius. It is radiating about 332^[6] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,920 K.^[6] The star is roughly 10^[7] billion years old and is spinning with a projected rotational velocity of 5.1 km/s.^[4]