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3 Andromedae

3 Andromedae

3 Andromedae (circled) in a close northerly run-of-stars asterism – 5, 7, 8, 11 being close by, south-westward.
Observation data Epoch J2000      Equinox J2000
Constellation	Andromeda
Right ascension	23h04m 10.98269s[1]
Declination	+50° 03′ 07.5255″[1]
Apparent magnitude (V)	4.64[2]
Characteristics
Evolutionary stage	giant[3]
Spectral type	K0 IIIb[4]
B−V color index	1.058±0.003[2]
Astrometry
Radial velocity (Rv)	−34.87±0.12[1] km/s
Proper motion (μ)	RA: 165.837[1] mas/yr[1] Dec.: 167.716 mas/yr[1]
Parallax (π)	17.2629 ± 0.0918 mas[1]
Distance	189 ± 1 ly (57.9 ± 0.3 pc)
Absolute magnitude (MV)	0.97[2]
Details
Mass	1.71[5] M☉
Radius	10[6] R☉
Luminosity	49[5] L☉
Surface gravity (log g)	2.61±0.11[7] cgs
Temperature	4,668±45[5] K
Metallicity [Fe/H]	−0.08[3] dex
Rotational velocity (v sin i)	1.0[8] km/s
Age	2.27[5] Gyr
Other designations
3 And, BD+49° 4028, HD 218031, HIP 113919, HR 8780, SAO 52649, PPM 41448, LTT 16772[9]
Database references
SIMBAD	data

3 Andromedae, abbreviated 3 And, is a single^[10] star in the northern constellationofAndromeda. 3 Andromedae is the Flamsteed designation. It is visible to the naked eye with an apparent visual magnitude of 4.64.^[2] The distance to this star, as determined from an annual parallax shiftof17.3 mas,^[1] is 181 light years. It is moving closer to the Earth with a heliocentric radial velocity of −35 km/s,^[11] and has a relatively large proper motion, traversing the celestial sphereat0.236″·yr⁻¹.^[12]

This is an evolved giant star with a stellar classification of K0 IIIb,^[4] where the 'b' suffix indicated a lower luminosity giant. It is a red clump star,^[3] which means it is generating energy through helium fusion at its core. This star has an estimated 1.7^[5] times the mass of the Sun (M_☉), and, at the age of 2.3^[5] billion years, has expanded to 10 times the Sun's radius (R_☉).^[6] It is radiating 49^[5] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,668 K.^[5]

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