Phi Orionis
| Phi Orionis | |
|---|---|
| Observational Data | |
| Designation | φ Orionis 37 Orionis |
| Right ascension | 05h 34m 49.2380s[1][2] |
| Declination | +09° 29′ 22.4878″[1][2] |
| Constellation | Orion |
| Type of object | Main sequence star |
| Magnitude | Apparent Mag: +4.39[3] Absolute Mag: -3.01 / -3.22[3] |
| Astrometry | |
| Distance from Earth | 1087.21 ly[3] |
| Radial velocity | 33.2 ± 0.9 km/s[1][4] |
| Proper motion | RA: 0.27 mas/yr[1][2] Dec: -2.26 mas/yr[1][2] |
| Parallax | 3.00 ± 0.25 mas[1][2] |
Phi Orionis (37 Orionis, φ Orionis) is a main sequence star in the constellation of Orion.[5] The name "Phi Orion" actually refers to two unrelated stars in Orion that happen to appear near each other, designated Phi-1 Orion and Phi-2 Orion (sometimes written with superscripts as Phi1 Orionis and Phi2 Orionis.)[6] They are separated by 0.71° degrees in the night sky and along with the star Meissa, form a lesser known triangle.[7] The two stars along with Lambda Orionis are situated in a red emission nebula designated Sh2-264.[8] Here we mainly consider Phi-1 Orion.
Phi-1 Orionis is located nine times further away from Earth than Phi-2 Orionis at a distance of 1087.21 light years.[3] The star is significantly larger than the Sun with a mass of 14 solar masses and a radius 6.9 times larger than Sol's.[5] Its extraordinarily high surface temperature of 28,900 kelvin means it radiates vast quantities of radiation in the ultraviolet portion of the electromagnetic spectrum. It also contributes to Phi-1 Orionis' high luminosity of 29,650 times larger than the Sun's.[5] It's equator rotates at 28 kilometers per second, or equivalently the star rotates with a period of just under 12.3 days, fairly slow compared to most stars. The star is known from spectroscopy to have a companion star, making it a binary system.[9] They orbit each other with a period of 8.4 years and an orbital separation of 10 Astronomical units.[5]
Phi-2 Orionis
Phi-2 Orionis (Flamsteed designation 40 Orionis) is a hypergiant star and is situated much closer than Phi-1 Orionis, at around 117.48 light years.[10][11] It is slightly brighter in the night sky than its counterpart at magnitude +4.1 as it is much closer; intrinsically it is only 34.8 times brighter than the Sun.[12] It is 6.95 times the size of the Sun and has a surface temperature of 4,948 Kelvin.
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 37 Orionis. Simbad Astronomical Database. simbad.u-strasbg.fr. Retrieved on July 09, 2020.
- ↑ 2.0 2.1 2.2 2.3 2.4 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy & Astrophysics 474 (2): 653-664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V. arXiv:0708.1752
- ↑ 3.0 3.1 3.2 3.3 Phi1 Orionis (37 Orionis) Star Facts. universeguide.com. Retrieved on July 09, 2020.
- ↑ Wilson, Raplh Elmer (1953). "General Catalogue of Stellar Radial Velocities". Washington, [Carnegie Institution of Washington]. Bibcode: 1953GCRV..C......0W.
- ↑ 5.0 5.1 5.2 5.3 Jim Kaller (February 02, 2012). PHI-1 ORI. Stars. stars.astr.illinois.edu. Retrieved on July 09, 2020.
- ↑ Phi1 Orionis. glyphweb.com. Retrieved on July 09, 2020.
- ↑ Orion Constellation. constellation-guide. Retrieved on July 09, 2020.
- ↑ CCD optical image of nebula around Lambda Orionis. sciencephoto.com. Retrieved on July 09, 2020.
- ↑ Struve, O. (1926). "Preliminary orbit of the long-period spectroscopic binary 37 phi-1 Orionis.". Astrophysical Journal 63: 60-66. doi:10.1086/142950. Bibcode: 1926ApJ....63...60S.
- ↑ φ Orionis. informationaboutstars.com. Retrieved on July 09, 2020.
- ↑ φ2 Orionis (phi2 Orionis). theskylive.com. Retrieved on July 09, 2020.
- ↑ Phi2 Orionis (40 Orionis) Star Facts. universeguide.com. Retrieved on July 09, 2020.
