Epsilon2 Arae
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ara |
| Right ascension | 17h 03m 08.754s |
| Declination | −53° 14′ 12.97″ |
| Apparent magnitude (V) | 5.270 (5.44 + 8.65) |
| Characteristics | |
| Spectral type | F5 V Fe+0.5 + DA3.2 |
| U−B color index | +0.015 |
| B−V color index | +0.498±0.005 |
| Astrometry | |
| Radial velocity (Rv) | +4.9 km/s |
| Proper motion (μ) | RA: −22.409 mas/yr Dec.: −143.793 mas/yr |
| Parallax (π) | 37.3696±0.1347 mas |
| Distance | 87.3 ± 0.3 ly (26.76 ± 0.10 pc) |
| Absolute magnitude (MV) | 3.27 |
| Orbit | |
| 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 M☉ |
| Radius | 1.8 R☉ |
| Luminosity | 4.56 L☉ |
| Surface gravity (log g) | 4.29 cgs |
| Temperature | 6,577 K |
| Metallicity [Fe/H] | +0.02 dex |
| Rotational velocity (v sin i) | 45.4 km/s |
| Age | 1.77+0.29 −0.26 Gyr |
| ε2 Ara C | |
| Mass | 0.66±0.07 M☉ |
| Radius | 0.0124±0.0003 R☉ |
| Surface gravity (log g) | 8.07±0.04 cgs |
| Temperature | 15,507±230 K |
| Other designations | |
| CPD−53°8316, GC 22956, GJ 3985, HD 153580, HIP 83431, HR 6314, SAO 244388, PPM 345633, WDS J17031-5314A | |
| Database references | |
| SIMBAD | data |
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, this system is faintly visible to the naked eye as a point of light.
The brighter star is a magnitude 5.44 F-type main sequence star with a stellar classification of F5 V Fe+0.5. 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 billion years and a relatively high rate of rotation with a projected rotational velocity of 45 km/s. This star has 1.4 times the mass of the Sun and 1.8 times the Sun's radius. It is radiating 4.56 times the luminosity of the Sun from its photosphere at an effective temperature of 6,577 K. The metallicity of the star, a measure of the abundance of more massive elements, is similar to the Sun. It is a candidate pulsating star.
There is a magnitude 8.65 stellar companion, component Ab, at an angular separation of 0.590 arcseconds. The pair have an estimated orbital period of 41.3 years. 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.