| |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ara |
| Right ascension | 17h35m 39.58957s[1] |
| Declination | –46° 30′ 20.4618″[1] |
| Apparent magnitude (V) | +4.575[2] |
| Characteristics | |
| Spectral type | A0 V[3] |
| U−B color index | –0.064[2] |
| B−V color index | –0.027[2] |
| Astrometry | |
| Proper motion (μ) | RA: –25.78[1] mas/yr Dec.: –38.30[1] mas/yr |
| Parallax (π) | 8.62 ± 0.26 mas[1] |
| Distance | 380 ± 10 ly (116 ± 3 pc) |
| Absolute magnitude (MV) | 1.40[4] |
| Details | |
| Luminosity (bolometric) | 26.4[4] L☉ |
| Temperature | 9,790[4] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
Sigma Arae (σ Ara, σ Arae) is the Bayer designation for a star in the southern constellationofAra. It is visible to the naked eye with an apparent visual magnitude of +4.575.[2] The distance to this star, based upon an annual parallax shift of 8.62 mas,[1] is around 380 light-years (120 parsecs).
This is an A-type main sequence star with a stellar classification of A0 V.[3] Unusually for an A-type star, X-ray emissions with a luminosity of 4.6 × 1029 erg s−1 have been detected from Sigma Arae. Normally this is explained by the presence of a lower mass orbiting companion star. However, such a scenario does not appear to hold true for this star. Instead, the signature of a surface magnetic field has been detected with a strength of roughly 128 ± 73 Gauss, indicating the source of the X-rays may be surface magnetic activity.[6]
{{cite web}}: CS1 maint: postscript (link)
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