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Star in the constellation Scutum From Wikipedia, the free encyclopedia
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.[2] Based upon an annual parallax shift of 16.38 mas as seen from the Earth,[1] 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.[4]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Scutum |
Right ascension | 18h 35m 12.42776s[1] |
Declination | −8° 14′ 38.6529″[1] |
Apparent magnitude (V) | 3.83[2] |
Characteristics | |
Spectral type | K3III[3] |
U−B color index | +1.53[2] |
B−V color index | +1.34[2] |
Astrometry | |
Radial velocity (Rv) | +36.50[4] km/s |
Proper motion (μ) | RA: −17.00[1] mas/yr Dec.: −313.52[1] mas/yr |
Parallax (π) | 16.38 ± 0.22 mas[1] |
Distance | 199 ± 3 ly (61.1 ± 0.8 pc) |
Absolute magnitude (MV) | −0.08[5] |
Details | |
Mass | 1.33[6] M☉ |
Radius | 20[6] R☉ |
Luminosity | 186[5] L☉ |
Surface gravity (log g) | 1.96[6] cgs |
Temperature | 4,315[7] K |
Metallicity [Fe/H] | −0.04[5] dex |
Rotational velocity (v sin i) | 1.7[8] km/s |
Other designations | |
Database references | |
SIMBAD | data |
With a stellar classification of K3 III,[3] 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[5] times the Sun's luminosity from its inflated photosphere at an effective temperature of 4,315 K.[7]