Psi2 Orionis

For other stars with this Bayer designation, see Psi Orionis.
ψ2 Orionis

A light curve for Psi2 Orionis plotted from TESS data[1]
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Orion
Right ascension 05h 26m 50.22932s[2]
Declination +03° 05′ 44.4222″[2]
Apparent magnitude (V) 4.55 (- 4.58) - 4.61[3]
Characteristics
Spectral type B2 IV[4] (B1 III + B2 V)[5]
U−B color index −0.94[6]
B−V color index −0.22[6]
Variable type Eclipsing[3]
Astrometry
Radial velocity (Rv)+19[7] km/s
Proper motion (μ) RA: +1.448[2] mas/yr
Dec.: −1.019[2] mas/yr
Parallax (π)2.9943 ± 0.1533 mas[2]
Distance1,090 ± 60 ly
(330 ± 20 pc)
Absolute magnitude (MV)−2.71[8]
Orbit[7]
Period (P)2.529 d
Eccentricity (e)0.053
Inclination (i)58±8°
Periastron epoch (T)2450774 JD
Argument of periastron (ω)
(secondary)		172°
Semi-amplitude (K1)
(primary)		145 km/s
Semi-amplitude (K2)
(secondary)		237 km/s
Details
primary
Mass9.6[9] M☉
Luminosity10,252[4] L☉
Surface gravity (log g)3.5[10] cgs
Temperature25,000[10] K
Rotational velocity (v sin i)95±5[10] km/s
Age11.4[7] Myr
secondary
Mass7.06[9] M☉
Surface gravity (log g)3.5[10] cgs
Temperature22,500[10] K
Rotational velocity (v sin i)75±5[10] km/s
Other designations
ψ2 Ori, 30 Orionis, BD+02°962, HD 35715, HIP 25473, HR 1811, SAO 112775.[11]
Database references
SIMBADdata

Psi2 Orionis a binary star system in the equatorial constellation of Orion. It has an apparent visual magnitude of 4.6, indicating that it is visible to the naked eye. Based upon an annual parallax shift of 2.87 mass, it is roughly 1,100 light years distant from the Sun.

This is a double-lined spectroscopic binary,[5] which means that the individual absorption lines of both components can be discerned. The pair orbit each other with a period of 2.526 days and a low eccentricity of 0.04.[10] The close orbit is causing their mutual gravitational interaction to distort the shapes of the stars, turning this system into an ellipsoidal variable.[12] The inclination of orbital plane is sufficiently low that the two stars form a grazing eclipsing binary. During the eclipse of the primary component, the visual magnitude is reduced by 0.06, whereas the secondary eclipse reduces the magnitude by 0.03.[13] The brightness variability has led to the star being classified as a pulsating Beta Cephei variable, but no evidence has been found of pulsations superimposed on the variability due to ellipsoidal rotations and eclipses.[14][7]

The combined spectrum of Psi2 Orionis matches that of a B-type subgiant star with a stellar classification of B2 IV.[4] The primary component is an evolved giant star with a class of B1 III, while the secondary is a B-type main sequence star with a classification of B2 V.[5]

  1. ^ Cite error: The named reference MAST was invoked but never defined (see the help page).
  2. ^ a b c d e Cite error: The named reference edr3 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference gcvs was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Neuhaeuser2010 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Crawford1971 was invoked but never defined (see the help page).
  7. ^ a b c d Cite error: The named reference telting2001 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference melnik2020 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference msc was invoked but never defined (see the help page).
  10. ^ a b c d e f g Cite error: The named reference wu1985 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Beech1989 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference lefevre2009 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Waelkens1983 was invoked but never defined (see the help page).