Location of ε Piscis Austrini (circled) | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Piscis Austrinus |
| Right ascension | 22 40 39.34075 |
| Declination | −27° 02′ 37.0157″ |
| Apparent magnitude (V) | +4.17 |
| Characteristics | |
| Spectral type | B8 Ve or B8 IVe |
| U−B color index | −0.31 |
| B−V color index | −0.11 |
| Astrometry | |
| Radial velocity (Rv) | +1.1±2.8 km/s |
| Proper motion (μ) | RA: +23.22 mas/yr Dec.: −0.16 mas/yr |
| Parallax (π) | 8.0981 ± 0.3582 mas |
| Distance | 400 ± 20 ly (123 ± 5 pc) |
| Absolute magnitude (MV) | −1.66 |
| Details | |
| Mass | 4.10±0.19 M☉ |
| Radius | 3.2 R☉ |
| Luminosity | 661 L☉ |
| Surface gravity (log g) | 3.93 cgs |
| Temperature | 11,066 K |
| Rotational velocity (v sin i) | 216 km/s |
| Other designations | |
| ε PsA, 18 Piscis Austrini, CPD−27° 7442, FK5 854, HD 214748, HIP 111954, HR 8628, SAO 191318 | |
| Database references | |
| SIMBAD | data |
Epsilon Piscis Austrini, Latinized from ε Piscis Austrini, is a blue-white hued star in the southern constellation of Piscis Austrinus. It is visible to the naked eye with an apparent visual magnitude of +4.17. Based upon an annual parallax shift of 8.0981 ± 0.3582 mas as seen from the Gaia satellite, the system is located roughly 400 light years from the Sun.
This is a B-type main sequence star with a stellar classification of B8 Ve. It is a Be star that is spinning rapidly with a projected rotational velocity of 216 km/s, compared to an equatorial critical velocity of 301 km/s. The star has 4.1 times the mass of the Sun and is radiating 661 times the solar luminosity from its photosphere at an effective temperature of 11,066 K.
Epsilon Piscis Austrini is moving through the Galaxy at 18.7 km/s relative to the Sun. Its projected Galactic orbit carries it between 23,917 and 28,138 light-years from the center of the Galaxy.
Naming
In Chinese, 羽林軍 (Yǔ Lín Jūn), meaning Palace Guard, refers to an asterism consisting of:
- ε Piscis Austrini
- 29 Aquarii
- 35 Aquarii
- 41 Aquarii
- 47 Aquarii
- 49 Aquarii
- λ Piscis Austrini
- HD 212448
- 21 Piscis Austrini
- 20 Piscis Austrini
- υ Aquarii
- 68 Aquarii
- 66 Aquarii
- 61 Aquarii
- 53 Aquarii
- 50 Aquarii
- 56 Aquarii
- 45 Aquarii
- 58 Aquarii
- 64 Aquarii
- 65 Aquarii
- 70 Aquarii
- 74 Aquarii
- τ Aquarii
- τ Aquarii
- δ Aquarii
- 77 Aquarii
- 88 Aquarii
- 89 Aquarii
- 86 Aquarii
- 101 Aquarii
- 100 Aquarii
- 99 Aquarii
- 98 Aquarii
- 97 Aquarii
- 94 Aquarii
- ψAquarii
- ψAquarii
- ψAquarii
- 87 Aquarii
- 85 Aquarii
- 83 Aquarii
- χ Aquarii
- ω Aquarii
- ω Aquarii
Consequently, the Chinese name for ε Piscis Austrini itself is 羽林軍八 (Yǔ Lín Jūn bā, English: the Eighth Sixth Star of Palace Guard.)
References
- ^ van Leeuwen, F. (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.
- ^ Feinstein, A.; Marraco, H. G. (November 1979), "The photometric behavior of Be Stars", Astronomical Journal, 84: 1713–1725, Bibcode:1979AJ.....84.1713F, doi:10.1086/112600.
- ^ Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590.
- ^ 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.
- Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 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.
- ^ 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.
- ^ Zorec, J.; Royer, F. (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)", Astronomy and Astrophysics, 367 (3rd ed.): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
- ^ Chauville, J.; et al. (November 2001), "High and intermediate-resolution spectroscopy of Be stars 4481 lines", Astronomy and Astrophysics, 378: 8618–82, Bibcode:2001A&A...378..861C, doi:10.1051/0004-6361:20011202, hdl:11336/36962.
- "eps PsA -- Be Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-05-18.
- 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.
- (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 7 日 Archived 2011-05-21 at the Wayback Machine
