Lambda Arae

Lambda Arae is a star in the southern constellation of Ara. Its name is a Bayer designation that is Latinized from λ Arae, and abbreviated Lambda Ara or λ Ara. The apparent visual magnitude of this star is 4.77,^[2] making it bright enough to be seen with the naked eye. Based on parallax measurements, it is located at a distance of 68 light-years (21 parsecs) from Earth. This star is drifting further away from the Sun with a radial velocity of +3 km/s.^[5]

Lambda Arae

Location of λ Arae (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Ara
Right ascension	17h 40m 23.826s[1]
Declination	−49° 24′ 56.10″[1]
Apparent magnitude (V)	4.77[2]
Characteristics
Spectral type	F4 V[3]
U−B color index	−0.04[2]
B−V color index	+0.40[2]
R−I color index	+0.22
Variable type	3.10[4]
Astrometry
Radial velocity (Rv)	+3.3±0.3[5] km/s
Proper motion (μ)	RA: +104.233 mas/yr[1] Dec.: −175.956 mas/yr[1]
Parallax (π)	47.7045±0.1368 mas[1]
Distance	68.4 ± 0.2 ly (20.96 ± 0.06 pc)
Absolute magnitude (MV)	+3.06[6]
Details
Mass	1.37±0.04[1] M☉
Radius	1.711±0.035[1] R☉
Luminosity	4.69+0.03 −0.05[1] L☉
Surface gravity (log g)	4.064+0.005 −0.003[1] cgs
Temperature	6,495+3 −7[1] K
Metallicity [Fe/H]	−0.24[4] dex
Rotational velocity (v sin i)	15.5[7] km/s
Age	2.44±0.39[1] Gyr
Other designations
λ Ara, λ Arae, NSV 23218, CD−49°11616, GC 23918, GJ 686.2, GJ 9597, HD 160032, HIP 86486, HR 6569, SAO 228257, PPM 323240, NLTT 45187[8]
Database references
SIMBAD	data

The spectrum of this star matches a stellar classification of F4 V,^[3] which places it among the category of F-type main sequence stars. It is an estimated 2.4 billion years old,^[1] and is spinning with a projected rotational velocity of 15.5 km/s.^[7] This star has 40% more mass than the Sun and a 70% greater radius. It shines with 4.7 times the luminosity of the Sun. The outer atmosphere is radiating this energy at an effective temperature of 6,495 K,^[1] giving it the yellow-white hue of an F-type star. There is some evidence that this may be a binary star system consisting of two stars with identical masses.^[7]

Examination of Lambda Arae with the Spitzer Space Telescope shows an excess of infrared emission at a wavelength of 70 μm. This suggests it may be orbited by a disk of dust at a radius of more than 15 astronomical units.^[9]