Eta Arae
 The location of η Arae (circled) |
|
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Ara |
| Right ascension | 16h 49m 47.15653s[1] |
| Declination | –59° 02′ 28.9575″[1] |
| Apparent magnitude (V) | 3.76[2] |
| Characteristics | |
| Spectral type | K5 III[3] |
| U−B color index | +1.93[2] |
| B−V color index | +1.57[2] |
| Astrometry | |
| Radial velocity (Rv) | +9.0[4] km/s |
| Proper motion (μ) | RA: +39.73[1] mas/yr Dec.: –24.91[1] mas/yr |
| Parallax (π) | 10.90 ± 0.20[1] mas |
| Distance | 299 ± 5 ly (92 ± 2 pc) |
| Absolute magnitude (MV) | –1.14 ± 0.14[5] |
| Details | |
| Mass | 1.02 ± 0.12[5] M☉ |
| Radius | 55.9 ± 7.3[5] R☉ |
| Surface gravity (log g) | 0.92 ± 0.12[5] cgs |
| Temperature | 3,886[5] K |
| Metallicity [Fe/H] | –0.37[5] dex |
| Age | 7.11 ± 2.34[5] Gyr |
| Other designations | |
Eta Arae (η Ara, η Arae) is the Bayer designation for a single [7] star in the southern constellation of Ara. It is approximately 299 light-years (92 parsecs) from Earth and is visible to the naked eye with an apparent visual magnitude of 3.76.[2]
The spectrum of this star matches a stellar classification of K5 III,[3] indicating that, at an estimated age of seven billion years,[5] it has reached the giant star stage of its evolution. With a mass nearly the same as the Sun, it has an outer envelope that has expanded to nearly 56 times the Sun's radius.[5] The star is now spinning so slowly that it takes more than eleven years to complete a single rotation.[8] Eta Arae is radiating energy into space at an effective temperature of 3,886 K,[5] giving it the orange-hued glow of a K-type star.[9]
It has a 14th magnitude optical companion, located 25.7 arcseconds away.
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 2.0 2.1 2.2 2.3 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 3.0 3.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
