Rho2 Arae is the Bayer designation for a star in the southern constellation of Ara. It received this designation when the star was catalogued by Bode in his Uranographia. This is a rather dim naked-eye star with an apparent visual magnitude of 5.54.[2] Based upon an annual parallax shift of just 6.28 mas, it is around 520 light-years (160 parsecs) distant from the Sun, give or take a 30-light-year margin of error.[1]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Ara |
Right ascension | 16h 58m 17.94161s[1] |
Declination | −50° 38′ 28.2691″[1] |
Apparent magnitude (V) | 5.54[2] |
Characteristics | |
Spectral type | B9 IV[3] or B9 V[4] |
B−V color index | +0.02[2] |
Astrometry | |
Radial velocity (Rv) | −44.0[5] km/s |
Proper motion (μ) | RA: −8.05[1] mas/yr Dec.: −38.68[1] mas/yr |
Parallax (π) | 6.28 ± 0.38 mas[1] |
Distance | 520 ± 30 ly (159 ± 10 pc) |
Absolute magnitude (MV) | −0.47[6] |
Details | |
Mass | 3.42 ± 0.10[7] M☉ |
Luminosity | 238[7] L☉ |
Temperature | 10,520[7] K |
Rotational velocity (v sin i) | 302[7] km/s |
Other designations | |
Database references | |
SIMBAD | data |
The spectrum of this star matches a stellar classification of B9 IV[3] or B9 V.[4] The IV luminosity class would indicate the star is in the subgiant stage, while a V class means it is a main-sequence star like the Sun. In the latter case, it is close to entering the subgiant stage at an estimated 93% of the way through its lifespan on the main sequence.[7]
Rho2 Arae has more than three times the mass of the Sun and shines with 238 times the Sun's luminosity.[7] This energy is being radiated into space from the outer atmosphere at an effective temperature of 10,520 K,[7] giving it the blue-white hue of a B-type star.[9] It is spinning rapidly with a projected rotational velocity of 302 km/s.[7]
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