Psi Scorpii

Psi Scorpii, which is Latinized from ψ Scorpii, is a star in the zodiac constellation of Scorpius. It is white in hue and has an apparent visual magnitude of 4.94,^[2] which is bright enough to be faintly visible to the naked eye. Based upon parallax measurements,^[1] it is located at a distance of around 162 light years from the Sun. Data collected during the Hipparcos mission suggests it is an astrometric binary, although nothing is known about the companion.^[11][12] The system is drifting closer to the Sun with a radial velocity of −5 km/s.^[4]

ψ Scorpii

Observation data Epoch J2000      Equinox J2000
Constellation	Scorpius
Right ascension	16h 12m 00.01043s[1]
Declination	−10° 03′ 50.8353″[1]
Apparent magnitude (V)	4.94[2]
Characteristics
Spectral type	A1 V[3]
U−B color index	+0.11[2]
B−V color index	+0.09[2]
Astrometry
Radial velocity (Rv)	−5.10[4] km/s
Proper motion (μ)	RA: −18.000[1] mas/yr Dec.: −36.188[1] mas/yr
Parallax (π)	20.1801±0.2617 mas[1]
Distance	162 ± 2 ly (49.6 ± 0.6 pc)
Absolute magnitude (MV)	+1.55[5]
Details
Mass	2.16±0.32[6] M☉
Radius	2.084±0.064[6] R☉
Luminosity	18.6[7] L☉
Surface gravity (log g)	4.134±0.071[6] cgs
Temperature	8,650±133[6] K
Rotational velocity (v sin i)	42.3±0.6[8] km/s
Age	451[9] Myr
Other designations
ψ Sco, 15 Scorpii, BD−09°4324, FK5 3280, GC 21780, HD 145570, HIP 79375, HR 6031, SAO 141022[10]
Database references
SIMBAD	data

The visible component is an A-type main sequence star with a stellar classification of A1 V;^[3] a class of star that is still fusing hydrogen at its core. It has around 2.2 the mass and 2.08 times the radius of the Sun,^[6] and is shining with 18.6 times the Sun's luminosity.^[7] The effective temperature of the star's outer atmosphere is 8,650 K.^[6] Psi Scorpii is around 451 million years old and is spinning with a projected rotational velocity of 42.3 km/s.^[9]