Alpha Scuti

Alpha Scuti, Latinized from α Scuti, is an orange-hued star in the southern constellation of Scutum. Originally part of the Aquila constellation, Alpha Scuti was a latter designation of 1 Aquilae.^[9] It is faintly visible to the naked eye with an apparent visual magnitude of 3.83.^[3] Based upon an annual parallax shift of 16.38 mas as seen from the Earth,^[2] it is located around 199 light years from the Sun. It is moving away from the Sun with a radial velocity of +36.5 km/s.^[5]

α Scuti

Location of α Scuti (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Scutum[1]
Right ascension	18h 35m 12.42776s[2]
Declination	−08° 14′ 38.6529″[2]
Apparent magnitude (V)	3.83[3]
Characteristics
Spectral type	K3III[4]
U−B color index	+1.53[3]
B−V color index	+1.34[3]
Astrometry
Radial velocity (Rv)	+36.50[5] km/s
Proper motion (μ)	RA: −17.00[2] mas/yr Dec.: −313.52[2] mas/yr
Parallax (π)	16.38±0.22 mas[2]
Distance	199 ± 3 ly (61.1 ± 0.8 pc)
Absolute magnitude (MV)	−0.08[1]
Details
Mass	1.33[6] M☉
Radius	20[6] R☉
Luminosity	186[1] L☉
Surface gravity (log g)	1.96[6] cgs
Temperature	4,315[7] K
Metallicity [Fe/H]	−0.04[1] dex
Rotational velocity (v sin i)	1.7[8] km/s
Other designations
α Sct, BD−08°4638, FK5 1482, GC 25385, HD 171443, HIP 91117, HR 6973, LTT 7377, NSV 11056, SAO 142408
Database references
SIMBAD	data

Properties

With a stellar classification of K3 III,^[4] the spectrum indicates it is an evolved giant star of type K. Alpha Scuti is a suspected variable star with magnitude range reported as 3.81 to 3.87.^[10] The star has an estimated 1.33 times the mass of the Sun, but the outer envelope has expanded to 20 times the Sun's radius.^[6] It is radiating 186^[1] times the Sun's luminosity from its inflated photosphere at an effective temperature of 4,315 K.^[7]