Delta Trianguli Australis

Delta Trianguli Australis (Delta TrA), Latinized from δ Trianguli Australis, is a solitary,^[14] yellow-hued star in the constellation Triangulum Australe. It has an apparent magnitude of 3.84,^[2] making it readily visible to the naked eye under ideal conditions, Parallax measurements place the object at a distance of 606 light years (182 parsecs).^[1] It has a heliocentric radial velocity of −4.9 km/s,^[5] indicating that it is drifting towards the Solar System.

δ Trianguli Australis

Location of δ TrA (circled)
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Triangulum Australe
Right ascension	16h 15m 26.26978s[1]
Declination	−63° 41′ 08.4492″[1]
Apparent magnitude (V)	3.84±0.01[2]
Characteristics
Spectral type	G2 Ib-IIa[3]
U−B color index	+0.87[4]
B−V color index	+1.10[4]
Astrometry
Radial velocity (Rv)	−4.9±0.7[5] km/s
Proper motion (μ)	RA: +2.73 mas/yr[1] Dec.: −12.92 mas/yr[1]
Parallax (π)	5.37±0.17 mas[1]
Distance	610 ± 20 ly (186 ± 6 pc)
Absolute magnitude (MV)	−2.49[6]
Details
Mass	6.51[7] M☉
Radius	53.6[8] R☉
Luminosity	1,210[9] L☉
Surface gravity (log g)	1.54[10] cgs
Temperature	4,705±122[8] K
Metallicity [Fe/H]	−0.05[10] dex
Rotational velocity (v sin i)	8.2±2[11] km/s
Other designations
δ TrA, 25 G. Trianguli Australis[12], CPD−63°3854, FK5 602, GC 21819, HD 145544, HIP 79664, HR 6030, SAO 253474, WDS J16154-6341A[13]
Database references
SIMBAD	data

Delta TrA has a stellar classification of G2 Ib-IIa^[3] — an evolved G-type star with a luminosity class intermediate between a low luminosity supergiant and a bright giant. At present it has 6.5 times the mass of the Sun^[7] and has an enlarged radius of 53.6 R_☉.^[8] It radiates at 1,210 times the luminosity of the Sun^[9] from its photosphere at an effective temperature of 4,705 K.^[8] Delta TrA has an iron abundance 89% that of the Sun,^[10] placing it around solar metallicity. It spins modestly with a projected rotational velocity of 8.2 km/s, which is high for stars of this type.^[11]