Theta1 Orionis A

For other stars with this Bayer designation, see θ Orionis.
θ1 Orionis A

Trapezium stars
Observation data
Epoch J2000      Equinox J2000
Constellation Orion
Right ascension 05h 35m 15.84743s[1]
Declination −05° 23′ 14.3441″[1]
Apparent magnitude (V) 6.72 - 7.65[2]
Characteristics
Spectral type B0.5V[3]
Variable type Algol[2]
Astrometry
Proper motion (μ) RA: 4.81±0.10[4] mas/yr
Dec.: −2.53±0.12[4] mas/yr
Parallax (π)2.626 ± 0.100 mas[4]
Distance1,240 ± 50 ly
(380 ± 10 pc)
Absolute magnitude (MV)−2.80[3]
Details
A1
Mass15.3[3] M☉
Radius4.5[3] R☉
Luminosity16,200[3] L☉
Surface gravity (log g)4.30[3] cgs
Temperature30,700[3] K
Age<2.5[3] Myr
A3
Mass2.5 - 2.7[5] M☉
Radius6.4[5] R☉
Details
A2
Mass4[6] M☉
Other designations
41 Ori A, V1016 Ori, BD−05 1315A, HD 37020, HIP 26220, HR 1893
Database references
SIMBADdata

Theta1 Orionis A (θ1 Ori A) is a variable trinary star in the constellation Orion. Its apparent magnitude range is 6.72 to 7.65 with a period of 65.432 days. It is one of the main stars in The Trapezium in Orion, along with B, C, and D, as well as the fainter E.

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