| |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ara |
| Right ascension | 18h06m 37.87129s[1] |
| Declination | –50° 05′ 29.3125″[1] |
| Apparent magnitude (V) | +3.67[2] |
| Characteristics | |
| Spectral type | B2 Ib[3] |
| U−B color index | –0.870[2] |
| B−V color index | –0.109[2] |
| Astrometry | |
| Radial velocity (Rv) | +3.4[4] km/s |
| Proper motion (μ) | RA: –8.27[1] mas/yr Dec.: –8.70[1] mas/yr |
| Parallax (π) | 4.01 ± 0.15 mas[1] |
| Distance | 810 ± 30 ly (249 ± 9 pc) |
| Absolute magnitude (MV) | −3.33[5] |
| Details | |
| Mass | 8.9 ± 0.1[6] M☉ |
| Radius | 20.1[7] R☉ |
| Luminosity | 3,450[5] L☉ |
| Surface gravity (log g) | 2.70[8] cgs |
| Temperature | 17,231 ± 231[7] K |
| Rotational velocity (v sin i) | 95[9] km/s |
| Age | 28.2 ± 4.7[6] Myr |
| Other designations | |
θ Ara, CD−50° 11720, FK5 1471, HD 165024, HIP 88714, HR 6743, SAO 245242.[10] | |
| Database references | |
| SIMBAD | data |
Theta Arae, Latinized from θ Arae, is the Bayer designation for a star in the constellation Ara. It has an apparent visual magnitude of +3.67,[2] which is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 4.01 mas,[1] Theta Arae is 810 light-years (250 parsecs) distant from the Earth.
This is a supergiant star with a stellar classification of B2 Ib.[3] It has nearly nine[6] times the mass of the Sun and is over 20[7] times the Sun's radius. The outer atmosphere of this star has an effective temperature of 17,231 K;[7] much hotter than the surface of the Sun. At this heat, the star shines with the characteristic blue-white hue of a B-type star.[11]
{{cite web}}: CS1 maint: postscript (link)
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