Beta Scorpii

β Scorpii
Location of β Scorpii (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Scorpius
HR 5984
Right ascension 16h 05m 26.23198s[1]
Declination –19° 48′ 19.6300″[1]
Apparent magnitude (V) 2.62[2]
HR 5985
Right ascension 16h 05m 26.57128s[1]
Declination –19° 48′ 06.8556″[1]
Apparent magnitude (V) 4.92[2]
Characteristics
HR 5984
Spectral type B1V[3] (B0.5IV-V + B1.5V)[4]
U−B color index –0.08[5]
B−V color index –0.08[5]
HR 5985
Spectral type B2V[3]
U−B color index –0.70[5]
B−V color index –0.02[5]
Astrometry
HR 5984
Radial velocity (Rv)–1.0[6] km/s
Proper motion (μ) RA: –5.20[1] mas/yr
Dec.: –24.04[1] mas/yr
Parallax (π)8.07 ± 0.78 mas[1]
Distance400 ± 40 ly
(120 ± 10 pc)
Absolute magnitude (MV)–3.92 / –2.60[7]
HR 5985
Radial velocity (Rv)–3.6[6] km/s
Proper motion (μ) RA: –5.07[1] mas/yr
Dec.: –25.87[1] mas/yr
Parallax (π)8.19 ± 1.17 mas[1]
Distanceapprox. 400 ly
(approx. 120 pc)
Absolute magnitude (MV)–1.83 (Ea: +0.24)[7]
Details[7]
β Sco Aa
Mass15.0 M
Radius6.3 R
Luminosity31,600 L
Temperature28,000 K
β Sco Ab
Mass10.4 M
Radius4.0 R
Luminosity7,900 L
Temperature26,400 K
β Sco C
Mass8.2 M
Radius2.9 R
Luminosity3,200 L
Surface gravity (log g)3.8 cgs
Temperature24,000 K
Rotational velocity (v sin i)55 km/s
β Sco Ea
Mass3.5 M
Radius2.4 R
Luminosity126 L
Surface gravity (log g)4.2 cgs
Temperature13,000 K
Rotational velocity (v sin i)5 km/s
Age6.3 Myr
Other designations
Acrab, Elacrab, Graffias, 8 Scorpii, ADS 9913, WDS J16054-1948
β1 Sco: BD–19 4307, HD 144217, HIP 78820, HR 5984
β2 Sco: BD–19 4308, HD 144218, HIP 78821, HR 5985
Database references
SIMBADβ Scorpii
β1 Scorpii
β2 Scorpii

Beta Scorpii (β Scorpii, abbreviated Beta Sco, β Sco) is a multiple star system in the southern zodiac constellation of Scorpius. It bore the traditional proper name of Acrab /ˈækræb/,[8] though the International Astronomical Union now regards that name as applying only to the β Scorpii Aa component.

  1. ^ a b c d e f g h i j Cite error: The named reference aaa474_2_653 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Hoffleit1991 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference mk was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference holmgren was invoked but never defined (see the help page).
  5. ^ a b c d Cite error: The named reference clpl4_99 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference rgcrv was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference catanzaro was invoked but never defined (see the help page).
  8. ^ Rumrill, H. B. (June 1936). "Star Name Pronunciation". Publications of the Astronomical Society of the Pacific. 48 (283). San Francisco, California: 139. Bibcode:1936PASP...48..139R. doi:10.1086/124681. S2CID 120743052.