Pi Boötis

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Pi Boötis
Observation data
Epoch J2000      Equinox J2000
Constellation Boötes
Right ascension 14h 40m 43.5668s
Declination +16° 25′ 05.967″
Apparent magnitude (V) 4.91
Spectral type B9pMnHgSi
U−B color index -0.31
B−V color index -0.03
R−I color index -0.02
Radial velocity (Rv) -0.6 km/s
Proper motion (μ) RA: 9.64 mas/yr
Dec.: 9.46 mas/yr
Parallax (π) 10.28 ± 0.91 mas
Distance 320 ± 30 ly
(97 ± 9 pc)
Absolute magnitude (MV) –0.39[1]
Mass 3.49 ± 0.14[1] M
Radius 3.2 ± 0.4[1] R
Luminosity 214[1] L
Surface gravity (log g) 3.98 ± 0.09[1] cgs
Temperature 12,417[1] K
Other designations
29 Boötis, BD+17°2768, HIP 71762
π1 Boötis: HD 129174, HR 5475, SAO 101138
π2 Boötis: HD 129175, HR 5476, SAO 101139
Database references
Data sources:
Hipparcos Catalogue,
CCDM (2002),
Bright Star Catalogue (5th rev. ed.)
Database references

Pi Boötis (π Boötis, π Boo) is a double star in the constellation Boötes. It is approximately 317 light years from Earth.

The brighter component (π1 Boötis) is a blue-white B-type main sequence dwarf with an apparent magnitude of +4.49. Its companion (π2 Boötis) is a white A-type main sequence dwarf with an apparent magnitude of +5.88. The stars are separated by 5.6 arcseconds on the sky.

Pi Boötis has the Chinese traditional star name 左攝提二 (Zuǒ shè tí èr)


  1. ^ a b c d e f North, P. (June 1998), "Do SI stars undergo any rotational braking?", Astronomy and Astrophysics, 334: 181–187, Bibcode:1998A&A...334..181N, arXiv:astro-ph/9802286Freely accessible 

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