Epsilon2 Arae

For other star systems with this Bayer designation, see Epsilon Arae.

Epsilon² Arae is a double star in the southern constellation of Ara. Its name is a Bayer designation that is Latinized from ε² Arae, and abbreviated Epsilon² Ara or ε² Ara. Based on parallax measurements, it is 89 light-years (27 parsecs) distant from Earth. With a combined apparent visual magnitude of 5.27,^[2] this system is faintly visible to the naked eye as a point of light.

Epsilon² Arae

The location of ε2 Arae (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Ara
Right ascension	17h 03m 08.754s[1]
Declination	−53° 14′ 12.97″[1]
Apparent magnitude (V)	5.270[2] (5.44 + 8.65)[3]
Characteristics
Spectral type	F5 V Fe+0.5[4] + DA3.2[5]
U−B color index	+0.015[6]
B−V color index	+0.498±0.005[2]
Astrometry
Radial velocity (Rv)	+4.9[7] km/s
Proper motion (μ)	RA: −22.409 mas/yr[1] Dec.: −143.793 mas/yr[1]
Parallax (π)	37.3696±0.1347 mas[1]
Distance	87.3 ± 0.3 ly (26.76 ± 0.10 pc)
Absolute magnitude (MV)	3.27[8]
Orbit[9]
Primary	ε2 Ara Aa
Companion	ε2 Ara Ab
Period (P)	41.3 yr
Semi-major axis (a)	0.589″
Eccentricity (e)	0.622
Inclination (i)	133.8°
Longitude of the node (Ω)	73.6°
Details
ε2 Ara Aa
Mass	1.40+0.01 −0.02[10] M☉
Radius	1.8[2] R☉
Luminosity	4.56[2] L☉
Surface gravity (log g)	4.29[8] cgs
Temperature	6,577[8] K
Metallicity [Fe/H]	+0.02[8] dex
Rotational velocity (v sin i)	45.4[11] km/s
Age	1.77+0.29 −0.26[10] Gyr
ε2 Ara C
Mass	0.65[5] M☉
Temperature	15,570[5] K
Other designations
CPD−53°8316, GC 22956, GJ 3985, HD 153580, HIP 83431, HR 6314, SAO 244388, PPM 345633, WDS J17031-5314A[6]
Database references
SIMBAD	data

The brighter star is a magnitude 5.44 F-type main sequence star with a stellar classification of F5 V Fe+0.5.^[4] The Fe+0.5 notation indicates that it has a somewhat higher than normal abundance of iron. It has an estimated age of 1.8^[10] billion years and a relatively high rate of rotation with a projected rotational velocity of 45 km/s.^[11] This star has 1.4^[10] times the mass of the Sun and 1.8 times the Sun's radius.^[2] It is radiating 4.56^[2] times the luminosity of the Sun from its photosphere at an effective temperature of 6,577 K.^[8] The metallicity of the star, a measure of the abundance of more massive elements, is similar to the Sun.^[8] It is a candidate pulsating star.^[12]

There is a magnitude 8.65 stellar companion, component Ab, at an angular separation of 0.590 arcseconds.^[3] The pair have an estimated orbital period of 41.3 years.^[9] A common proper motion white dwarf companion, WD 1659-53, lies at an angular separation of 113.76″. Designated component C, it is magnitude 13.47 with a classification of DA3.2.^[13][5]