Pi1 Orionis

For other stars with this Bayer designation, see Pi Orionis.
π1 Orionis
Location of π1 Orionis (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Orion
Right ascension 04h 54m 53.72877s[1]
Declination +10° 09′ 02.9952″[1]
Apparent magnitude (V) 4.74[2]
Characteristics
Spectral type A3 Va[3]
U−B color index +0.09[2]
B−V color index +0.08[2]
Astrometry
Proper motion (μ) RA: +41.49[1] mas/yr
Dec.: −128.73[1] mas/yr
Parallax (π)28.04 ± 0.25 mas[1]
Distance116 ± 1 ly
(35.7 ± 0.3 pc)
Absolute magnitude (MV)1.76±0.08[4]
Details
Mass1.97±0.07[4] M☉
Radius1.67[5] R☉
Luminosity16.6[5] L☉
Surface gravity (log g)4.15[3] cgs
Temperature8,611[3] K
Metallicity [Fe/H]−1.24[3] dex
Rotational velocity (v sin i)120[6] km/s
Age100[5] Myr
Other designations
π1 Ori, 7 Orionis, BD+09°683, HD 31295, HIP 22845, HR 1570, SAO 94201[7]
Database references
SIMBADdata

Pi1 Orionis (π1 Ori, π1 Orionis) is a star in the equatorial constellation of Orion. It is faintly visible to the naked eye with an apparent visual magnitude of 4.74.[2] Based upon an annual parallax shift of 28.04 mas,[1] it is located about 116 light-years from the Sun.

This is an A-type main-sequence star with a stellar classification of A3 Va.[3] It is a Lambda Boötis star,[8] which means the spectrum shows lower-than-expected abundances for heavier elements.[9] Pi1 Orionis is a relatively young star, just 100 million years old,[5] and is spinning fairly rapidly with a projected rotational velocity of 120 km/s.[6] It has nearly double[4] the mass of the Sun and 167% of the Sun's radius. The star radiates 16.6[5] times the solar luminosity from its outer atmosphere at an effective temperature of 8,611 K.[3]

An infrared excess indicates there is a debris disk with a temperature of 80 K orbiting 49 AU from the star. The dust has a combined mass 2.2% that of the Earth.[5]

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Mermilliod1986 was invoked but never defined (see the help page).
  3. ^ a b c d e f Cite error: The named reference Gray2006 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Gerbaldi1999 was invoked but never defined (see the help page).
  5. ^ a b c d e f Cite error: The named reference Rhee2007 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Royer2007 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Gray1993 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Kamp2008 was invoked but never defined (see the help page).