S Orionis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion |
| Right ascension | 05h 29m 00.8948s[1] |
| Declination | −04° 41′ 32.748″[1] |
| Apparent magnitude (V) | 7.2 - 14.0[2] |
| Characteristics | |
| Evolutionary stage | AGB[3] |
| Spectral type | M6.5e - M9.5e[2] |
| U−B color index | +0.15[4] |
| B−V color index | +1.73[4] |
| Variable type | Mira[2] |
| Astrometry | |
| Proper motion (μ) | RA: 14.77[1] mas/yr Dec.: -10.87[1] mas/yr |
| Parallax (π) | 0.89 ± 2.08[1] mas |
| Distance | 480 ± 120[3] pc |
| Details | |
| Radius | 411 - 498[3] R☉ |
| Temperature | 2,173[5] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
S Orionis is a red giant star in the constellation Orion.
Variability
Pulsations of S Orionis, showing dust production and masers (ESO)
S Orionis is a Mira variable that pulsates with a 420‑day cycle, and varies in radius from 2.0 to 2.3 astronomical units.[3]
Companion
S Orionis is listed in the Washington Double Star Catalog as a double star with a tenth magnitude companion 47" away. The companion is G0 star HD 294176.[6]
Circumstellar environment
S Orionis is surrounded by masers and dust condensed from its cool stellar wind. The size of the dust shells varies as the star pulsates and changes temperature, from around 8 AU to 10 AU across. The positions of the masers have been measured very accurately using VLBI.[3]
References
- 1 2 3 4 5 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
- 1 2 3 Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
- 1 2 3 4 5 Wittkowski, M.; Boboltz, D. A.; Ohnaka, K.; Driebe, T.; Scholz, M. (2007). "The Mira variable S Orionis: Relationships between the photosphere, molecular layer, dust shell, and SiO maser shell at 4 epochs". Astronomy and Astrophysics. 470: 191. arXiv:0705.4614
. Bibcode:2007A&A...470..191W. doi:10.1051/0004-6361:20077168. - 1 2 Celis s., L. (1982). "Red variable stars. I - UBVRI photometry and photometric properties". Astronomical Journal. 87: 1791. Bibcode:1982AJ.....87.1791C. doi:10.1086/113268.
- ↑ McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (2012). "Fundamental parameters and infrared excesses of Hipparcos stars". Monthly Notices of the Royal Astronomical Society. 427: 343. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x.
- ↑ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
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