Eta1 Coronae Australis
Star in the constellation Corona Australis
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Eta1 Coronae Australis is a suspected astrometric binary[10] star system in the constellation of Corona Australis. Its name is a Bayer designation that is Latinized from η1 Coronae Australis, and abbreviated Eta1 CrA or η1 CrA. This system is visible to the naked eye as a dim, white-hued point of light with an apparent visual magnitude of 5.5.[2] Parallax measurements put it at a distance of 317 light-years (97 pc) 317 light-years away from the Sun.
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Corona Australis |
| Right ascension | 18h 48m 50.49216s[1] |
| Declination | −43° 40′ 48.1977″[1] |
| Apparent magnitude (V) | 5.456[2] |
| Characteristics | |
| Spectral type | A3V[3] |
| B−V color index | +0.13[4] |
| Astrometry | |
| Radial velocity (Rv) | −4.0±4.2[5] km/s |
| Proper motion (μ) | RA: 22.312[1] mas/yr Dec.: −14.139[1] mas/yr |
| Parallax (π) | 10.2735±0.1889 mas[1] |
| Distance | 317 ± 6 ly (97 ± 2 pc) |
| Absolute magnitude (MV) | 0.84[6] |
| Details | |
| Mass | 2.05±0.29[7] M☉ |
| Radius | 3.43±0.12[7] R☉ |
| Luminosity | 51[7] L☉ |
| Surface gravity (log g) | 3.68±0.07[7] cgs |
| Temperature | 8308±133[7] K |
| Metallicity [Fe/H] | −0.01[8] dex |
| Rotational velocity (v sin i) | 122.3[9] km/s |
| Age | 491[8] Myr |
| Other designations | |
| Eta1 CrA, CD−43°12841, FK5 1490, GC 25748, HD 173715, HIP 92308, HR 7062, SAO 229299 | |
| Database references | |
| SIMBAD | data |
The visible component is an A-type main-sequence star with a stellar classification of A3V,[3] which indicates it is generating energy through core hydrogen fusion. It has broad spectrum absorption lines associated with its rotation period, having a projected rotational velocity of 122.3 km/s.[9] At an estimated age of 491[8] million years, this star has 2.1 times the mass of the Sun and 3.4 times the Sun's radius.[7] It is radiating 51 times the luminosity of the Sun from its photosphere at an effective temperature of 8,308 K.[7]