Pi Herculis

Pi Herculis

Historical view of the Hercules constellation showing the star π Her as one of the Keystone stars.
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Hercules
Right ascension 17h 15m 02.83424s[1]
Declination +36° 48′ 32.9816″[1]
Apparent magnitude (V) +3.15[2]
Characteristics
Spectral type K3 II[3][4]
U−B color index +1.66[2]
B−V color index +1.45[2]
Variable type suspected[5]
Astrometry
Radial velocity (Rv)−25.57±0.20[6] km/s
Proper motion (μ) RA: −27.402 mas/yr[1]
Dec.: 2.925 mas/yr[1]
Parallax (π)8.8991 ± 0.1323 mas[1]
Distance367 ± 5 ly
(112 ± 2 pc)
Absolute magnitude (MV)−2.10+0.13
−0.12[7]
Details
Mass3.77±0.2[8] M☉
Radius64.02+0.89
−0.91[8] R☉
Luminosity1,176±67[8] L☉
Surface gravity (log g)1.42[9] cgs
Temperature4,223±53[8] K
Metallicity [Fe/H]−0.07[9] dex
Rotational velocity (v sin i)6.12[10] km/s
Age220±40[8] Myr
Other designations
Pi Herculis, 67 Herculis, BD+36°2844, FK5 643, HD 156283, HIP 84380, HR 6418, SAO 65890.
Database references
SIMBADdata

Pi Herculis (π Her, π Herculis) is a third-magnitude star in the constellation Hercules. As one of the four stars in the Keystone asterism (see yellow quadrangle), it is one of the constellation's more easily recognized. It has an apparent visual magnitude of +3.2,[11] which is visible to the naked eye and makes it one of its brighter members. The Gaia spacecraft mission estimated its distance at roughly 112 parsecs from Earth, or about 367 light years away.[1] The overall reduction in the star's visual magnitude due to extinction from the intervening cosmic dust is 0.11.[6]

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  8. ^ a b c d e Cite error: The named reference Baines2018 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference mnras374_2_664 was invoked but never defined (see the help page).
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