Pi Scorpii

Pi Scorpii
Location of π Scorpii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Scorpius
Right ascension 15h 58m 51.11324s[1]
Declination −26° 06′ 50.7886″[1]
Apparent magnitude (V) 2.890[2]
Characteristics
Spectral type B1 V + B2 V[3]
U−B color index −0.918[2]
B−V color index −0.187[2]
Variable type Eclipsing binary
Astrometry
Radial velocity (Rv)−3[4] km/s
Proper motion (μ) RA: −11.42[1] mas/yr
Dec.: −26.83[1] mas/yr
Parallax (π)5.57 ± 0.64 mas[1]
Distanceapprox. 590 ly
(approx. 180 pc)
Absolute magnitude (MV)−3.35[5]
Orbit[6]
Period (P)1.570103±0.000005 d[7]
Semi-major axis (a)~0.07 AU
Eccentricity (e)0.0
Inclination (i)~42°
Semi-amplitude (K1)
(primary)		124.1±1.5 km/s
Semi-amplitude (K2)
(secondary)		196.1±1.8 km/s
Details
π Sco A
Mass12.5±0.6[8] M☉
Radius5[6] R☉
Luminosity21,900[9] L☉
Temperature25,230[9] K
Rotation100[9]
Rotational velocity (v sin i)108[6] km/s
Age15.4±0.6[8]
12–14[9] Myr
π Sco B
Mass9 M☉
Radius4[6] R☉
Luminosity3000 L☉
Temperature21000 K
Rotational velocity (v sin i)87[6] km/s
Other designations
Fang, Pi Sco, π Sco, 6 Scorpii, CD−25° 11228, HD 143018, HIP 78265, HR 5944, SAO 183987, ADS 9862, WDS 15589-2607
Database references
SIMBADdata

Pi Scorpii or π Scorpii, is a triple star[10] system in the southern constellation of Scorpius. With a combined apparent magnitude of 2.9,[2] it can be easily seen with the naked eye. Parallax measurements yield an estimated distance of around 590 light-years (180 parsecs) from the Sun.[2]

It consists of a binary pair, designated Pi Scorpii A, with a more distant third companion, B. A's two components are themselves designated Pi Scorpii Aa (formally named Fang)[11] and Ab.

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