Kappa Scorpii

Kappa Scorpii, Latinized from κ Scorpii, is a binary star system in the southern constellation of Scorpius. With an apparent visual magnitude of 2.4, this star system is readily visible to the naked eye. Parallax measurements place it at an estimated distance of roughly 480 light-years (150 parsecs) from the Earth.

κ Scorpii
Location of κ Sco (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Scorpius
Right ascension 17h 42m 29.27520s
Declination −39° 01 47.9391
Apparent magnitude (V) 2.41 - 2.42
Characteristics
Spectral type B1.5 III
U−B color index −0.914
B−V color index −0.228
Variable type β Cephei
Astrometry
Radial velocity (Rv)−14.0 km/s
Proper motion (μ) RA: −6.05 mas/yr
Dec.: −25.54 mas/yr
Parallax (π)6.75 ± 0.17 mas
Distance480 ± 10 ly
(148 ± 4 pc)
Absolute magnitude (MV)−3.46
Orbit
Period (P)195.65 days
Eccentricity (e)0.488±0.005
Periastron epoch (T)92.7±0.5
Semi-amplitude (K1)
(primary)
48.0±0.3 km/s
Details
κ Sco A
Mass17 M
Radius6.8 R
Luminosity6,911 L
Surface gravity (log g)4.01 cgs
Temperature23,400 K
Rotation1.90 days
Rotational velocity (v sin i)105 km/s
Age25.1±1.3 Myr
κ Sco B
Mass12 M
Radius5.8 R
Surface gravity (log g)4.00 cgs
Temperature18,800 K
Other designations
Girtab, κ Sco, CD−38°12137, CPD−38°6992, FK5 660, HD 160578, HIP 86670, HR 6580, SAO 209163
Database references
SIMBADdata
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