Location of ε Arietis (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aries |
| Right ascension | 02 59 12.72536 |
| Declination | +21° 20′ 25.5575″ |
| Apparent magnitude (V) | 4.63 (5.2/5.5) |
| Characteristics | |
| Spectral type | A2 Vs + A2 Vs |
| U−B color index | +0.08 |
| B−V color index | +0.04 |
| R−I color index | 0.02 |
| Astrometry | |
| Radial velocity (Rv) | +0.9 ± 0.9 km/s |
| Proper motion (μ) | RA: -13.74 mas/yr Dec.: -5.12 mas/yr |
| Parallax (π) | 9.81 ± 0.79 mas |
| Distance | 330 ± 30 ly (102 ± 8 pc) |
| Orbit | |
| Period (P) | 704.111±1.778 yr |
| Semi-major axis (a) | 2.174±0.035″ |
| Eccentricity (e) | 0.317±0.006 |
| Inclination (i) | 84.2±0.8° |
| Longitude of the node (Ω) | 25.6±0.7° |
| Periastron epoch (T) | 704.111±1.778 |
| Argument of periastron (ω) (secondary) | 162.1±1.0° |
| Details | |
| ε Ari A | |
| Mass | 2.4 M☉ |
| Rotational velocity (v sin i) | 60 km/s |
| ε Ari B | |
| Mass | 2.4 M☉ |
| Rotational velocity (v sin i) | 60 km/s |
| Other designations | |
| 48 Arietis, BD+20 484, HIP 13914, ADS 2257, WDS J02592+2120AB | |
| ε Ari A: HD 18520, HR 888, SAO 75673 | |
| ε Ari B: HD 18519, HR 887. | |
| Database references | |
| SIMBAD | ε Ari |
| ε Ari A | |
| ε Ari B | |
Epsilon Arietis (ε Ari, ε Arietis) is the Bayer designation for a visual binary star system in the northern constellation of Aries. It has a combined apparent visual magnitude of 4.63 and can be seen with the naked eye, although the two components are too close together to be resolved without a telescope. With an annual parallax shift of 9.81 mas, the distance to this system can be estimated as 330 light-years (100 parsecs), give or take a 30 light-year margin of error. It is located behind the dark cloud MBM12.
The brighter member of this pair has an apparent magnitude of 5.2. At an angular separation of 1.426 ± 0.010 arcseconds from the brighter component, along a position angle of 209.2° ± 0.3°, is the magnitude 5.5 companion. Both are A-type main sequence stars with a stellar classification of A2 Vs. (The 's' suffix indicates that the absorption lines in the spectrum are distinctly narrow.) In the 2009 Catalogue of Ap, HgMn and Am stars, the two stars have a classification of A3 Ti, indicating they are Ap stars with an anomalous abundance of titanium. Within the measurement margin of error, their projected rotational velocities are deemed identical at 60 km/s.
Name
This star system, along with δ Ari, ζ Ari, π Ari, and ρ Ari, were Al Bīrūnī's Al Buṭain (ألبطين), the dual of Al Baṭn, the Belly. According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Buṭain were the title for five stars :δ Ari as Botein, π Ari as Al Buṭain I, ρ Ari as Al Buṭain II, ε Ari as Al Buṭain III and ζ Ari as Al Buṭain IV
In Chinese astronomy, Epsilon Arietis may be or may be part of Tso Kang (from Cantonese 左更 zogang, Mandarin pronunciation zuǒgēng).
References
- ^ van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
- ^ Eggen, Olin J. (November 1963), "Luminosities, colors, and motions of the brightest A-type stars", Astronomical Journal, 68: 697, Bibcode:1963AJ.....68..697E, doi:10.1086/109198.
- ^ Renson, P.; Manfroid, J. (May 2009), "Catalogue of Ap, HgMn and Am stars", Astronomy and Astrophysics, 498 (3): 961–966, Bibcode:2009A&A...498..961R, doi:10.1051/0004-6361/200810788.
- ^ Royer, F.; et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics, 393: 897–911, arXiv:astro-ph/0205255, Bibcode:2002A&A...393..897R, doi:10.1051/0004-6361:20020943, S2CID 14070763.
- Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
- ^ Rica, Francisco (April 2012), "Orbital Elements for BU 741 AB, STF 333 AB, BU 920 and R 207", Journal of Double Star Observations, 8 (2): 127–139, Bibcode:2012JDSO....8..127R.
- "eps Ari". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-08-05.
- ^ Scardia, M.; Prieur, J.-L.; Pansecchi, L.; Argyle, R. W.; Basso, S.; Sala, M.; Ghigo, M.; Koechlin, L.; Aristidi, E. (January 2007), "Speckle observations with PISCO in Merate - III. Astrometric measurements of visual binaries in 2005 and scale calibration with a grating mask" (PDF), Monthly Notices of the Royal Astronomical Society, 374 (3): 965–978, Bibcode:2007MNRAS.374..965S, doi:10.1111/j.1365-2966.2006.11206.x.
- Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York, NY: Dover Publications Inc. p. 83. ISBN 0-486-21079-0. Retrieved 2010-12-12.
- Jack W. Rhoads - Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars, Jet Propulsion Laboratory, California Institute of Technology; November 15, 1971
- Chevalier, S., and Tsuchihashi, P., (1911): "Catalogue d'Étoiles fixes, observés a Pekin sous l'Empereur Kien Long (Qianlong (Chien-Lung)), XVIII siecle", Annales de l'Observatoire Astronomique de Zô-Sé.
- 伊世同 (Yi Shi Tong) (1981): 『中西対照恒星図表』科学出版社.(in Chinese)
External links
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