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 mas[1] |
Distance | 299 ± 5 ly (92 ± 2 pc) |
Absolute magnitude (MV) | −1.14±0.14[5] |
Details[6] | |
Mass | 1.12±0.16 M☉ |
Radius | 40.44±2.62 R☉ |
Luminosity | 575 L☉ |
Surface gravity (log g) | 1.06±0.06 cgs |
Temperature | 4,147±29 K |
Metallicity [Fe/H] | −0.47±0.03 dex |
Rotational velocity (v sin i) | 1.55±0.55 km/s |
Age | 4.98±1.86 Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Eta Arae, Latinized from η Arae, is the Bayer designation for a single [8] 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 star is moving away from the Sun with a radial velocity of +9 km/s.[4]
The spectrum of this star matches a stellar classification of K5 III,[3] indicating that, at an estimated age of five billion years,[6] it has reached the giant star stage of its evolution. With 1.12 times the mass of the Sun, it has an outer envelope that has expanded to 40 times the Sun's radius.[6] The star is now spinning so slowly that it takes more than eleven years to complete a single rotation.[9] Eta Arae is radiating energy into space from its photosphere with 575 times the Sun's luminosity at an effective temperature of 4,147 K,[6] giving it the orange-hued glow of a K-type star.[10]
It has a magnitude 13.5 optical companion, located 23.4 arcseconds away along a position angle of 118°, as of 2000.[11]
aaa474_2_653
was invoked but never defined (see the help page).clpl4_99
was invoked but never defined (see the help page).houk1978
was invoked but never defined (see the help page).gcrv1953
was invoked but never defined (see the help page).aaa458_2_609
was invoked but never defined (see the help page).jofre2015
was invoked but never defined (see the help page).SIMBAD
was invoked but never defined (see the help page).mnras389_2_869
was invoked but never defined (see the help page).aaa421_241
was invoked but never defined (see the help page).csiro
was invoked but never defined (see the help page).wds2006
was invoked but never defined (see the help page).