Delta Arae

Delta Arae

δ Arae (lower center) in the Ara Constellation
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ara
Right ascension 17h 31m 05.91272s[1]
Declination –60° 41′ 01.8522″[1]
Apparent magnitude (V) 3.62[2]
Characteristics
Spectral type B8 Vn[3] + G8 V[4]
U−B color index –0.31[2]
B−V color index –0.10[2]
Astrometry
Radial velocity (Rv)+10[5] km/s
Proper motion (μ) RA: –54.01[1] mas/yr
Dec.: –99.25[1] mas/yr
Parallax (π)16.48 ± 0.34 mas[1]
Distance198 ± 4 ly
(61 ± 1 pc)
Absolute magnitude (MV)−0.31[6]
Details
Mass3.56[7] M☉
Radius3.12 ± 0.15[8] R☉
Luminosity214[6] L☉
Surface gravity (log g)3.81 ± 0.06[8] cgs
Temperature11,962 ± 86[8] K
Rotational velocity (v sin i)255[4] km/s
Age125[9] Myr
Other designations
δ Ara, CPD –60° 6842, FK5 648, HD 158094, HIP 85727, HR 6500, SAO 253945.[10]
Database references
SIMBADdata

Delta Arae, Latinized from δ Arae, is the Bayer designation for a double star in the southern constellation Ara. It has an apparent visual magnitude of 3.62[2] and is visible to the naked eye. Based upon an annual parallax of 16.48 mas, it is about 198 light-years (61 parsecs) distant from the Earth.[1]

Delta Arae is massive B-type main sequence star with a stellar classification of B8 Vn.[3] The 'n' suffix indicates the absorption lines are spread out broadly because the star is spinning rapidly. It has a projected rotational velocity of 255 km/s, resulting in an equatorial bulge with a radius 13% larger than the polar radius.[4] It has a magnitude 9.5 companion G-type main sequence star that may form a binary star system with Delta Arae.[7]

There is a 12th magnitude optical companion located 47.4 arcseconds away along a position angle of 313°.[9]

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  2. ^ a b c d Cite error: The named reference aass34_1 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference houk1979 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference aar20_1_51 was invoked but never defined (see the help page).
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  6. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference apjss192_1_2 was invoked but never defined (see the help page).
  8. ^ a b c Cite error: The named reference aj129_3_1642 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference aaa523_A73 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).