Location of σ Arietis (circled) | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Aries |
| Right ascension | 02 51 29.58618 |
| Declination | +15° 04′ 55.4438″ |
| Apparent magnitude (V) | +5.52 |
| Characteristics | |
| Spectral type | B7 V |
| U−B color index | –0.43 |
| B−V color index | –0.09 |
| Astrometry | |
| Radial velocity (Rv) | +17.0 km/s |
| Proper motion (μ) | RA: +29.843 mas/yr Dec.: –24.661 mas/yr |
| Parallax (π) | 6.8952 ± 0.2164 mas |
| Distance | 470 ± 10 ly (145 ± 5 pc) |
| Absolute magnitude (MV) | −0.38 |
| Details | |
| A | |
| Mass | 3.84±0.08 M☉ |
| Radius | 3 R☉ |
| Luminosity | 301 L☉ |
| Surface gravity (log g) | 4.0±0.25 cgs |
| Temperature | 13,121 K |
| Rotational velocity (v sin i) | 165 km/s |
| Age | 36+57 −27 Myr |
| B | |
| Mass | 1.0–1.2 M☉ |
| Temperature | 5,524±150 K |
| Metallicity | −0.5 dex |
| Rotational velocity (v sin i) | 5 km/s |
| Other designations | |
| σ Ari, 43 Arietis, BD+14 480, FK5 1079, HD 17769, HIP 13327, HR 847, SAO 93144 | |
| Database references | |
| SIMBAD | data |
Sigma Arietis, Latinized from σ Arietis, is the Bayer designation for a star in the northern constellation of Aries. It has an apparent visual magnitude of +5.52, which is bright enough for the star to be seen with the naked eye from dark suburban skies. The star is located at a distance of approximately 470 light-years (140 parsecs) from the Sun based on parallax, and is drifting further away with a radial velocity of +17 km/s. On November 20, 1952, it was observed being occulted by the planet Jupiter.
Sigma Arietis is a B-type main sequence star with a stellar classification of B7 V. This is a large star with three times the radius of the Sun and 3.8 times the Sun's mass. It shines around 301 times as brightly as the helium and oxeygen, with this energy being radiated into space from its outer atmosphere at a scorching hot effective temperature of 13,121 K. It is this heat that gives the star the blue-white hue of a B-type star. Sigma Arietis is spinning at a rapid clip, with a projected rotational velocity of 165 km/s. It is a probable member of the Cas-Tau OB association of stars that share a common motion through space.
In 2016, a stellar companion was reported based on observations using adaptive optics with the Gemini North Telescope.
References
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ Crawford, D. L.; Barnes, J. V.; Golson, J. C. (1971), "Four-color, H-beta, and UBV photometry for bright B-type stars in the northern hemisphere", The Astronomical Journal, 76: 1058, Bibcode:1971AJ.....76.1058C, doi:10.1086/111220.
- ^ Lesh, Janet Rountree (December 1968), "The Kinematics of the Gould Belt: an Expanding Group?", Astrophysical Journal Supplement, 17: 371, Bibcode:1968ApJS...17..371L, doi:10.1086/190179.
- ^ Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode:1999VeARI..35....1W.
- Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
- ^ Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics, 367 (2): 5211–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754
- ^ Gullikson, Kevin; et al. (August 2016), "The Close Companion Mass-ratio Distribution of Intermediate-mass Stars", The Astronomical Journal, 152 (2): 13, arXiv:1604.06456, Bibcode:2016AJ....152...40G, doi:10.3847/0004-6256/152/2/40, S2CID 119179065, 40.
- "sig Ari". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-18.
{{cite web}}: CS1 maint: postscript (link) - Salanave, Leon E. (February 1953), "Occultation of Sigma ARIETIS by Jupiter", Publications of the Astronomical Society of the Pacific, 65 (382): 48, Bibcode:1953PASP...65...48S, doi:10.1086/126529, S2CID 121458925.
- de Zeeuw, P. T.; et al. (January 1999), "A HIPPARCOS Census of the Nearby OB Associations", The Astronomical Journal, 117 (1): 354–399, arXiv:astro-ph/9809227, Bibcode:1999AJ....117..354D, doi:10.1086/300682, S2CID 16098861.
External links
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