Rho2 Arae

For other stars with this Bayer designation, see ρ Arietis.
Rho2
Diagram showing star positions and boundaries of the Ara constellation and its surroundings
The location of ρ2 Arae (circled)
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]
Distance520 ± 30 ly
(159 ± 10 pc)
Absolute magnitude (MV)−0.47[6]
Details
Mass3.42 ± 0.10[7] M☉
Luminosity238[7] L☉
Temperature10,520[7] K
Rotational velocity (v sin i)302[7] km/s
Other designations
ρ2 Ara, CD–50° 10924, FK5 1444, HD 152824, HIP 83057, HR 6289, SAO 244313[8]
Database references
SIMBADdata

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]

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]

  1. ^ a b c d e f Cite error: The named reference aaa474_2_653 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference mnrassa27_11 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference apj157_313 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference houk1978 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference scfs was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b c d e f g h Cite error: The named reference aaa537_A120 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference csiro was invoked but never defined (see the help page).