6 Equulei is a probable (95% chance) astrometric binary[9] star system in the northern constellation of Equuleus, located 380 light years from the Sun. It is barely visible to the naked eye as a dim, white-hued star with an apparent visual magnitude of 6.07.[2] The system is moving further away from the Earth with a heliocentric radial velocity of +6.9 km/s.[5] It forms a wide optical double with γ Equulei, at an angular separation of 336 arcseconds in 2011.[10]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Equuleus |
| Right ascension | 21h 10m 31.31996s[1] |
| Declination | 10° 02′ 56.1180″[1] |
| Apparent magnitude (V) | 6.07[2] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | A2 Vs[3] (A1 Si Sr Cr)[4] |
| U−B color index | +0.04[2] |
| B−V color index | +0.02[2] |
| Astrometry | |
| Radial velocity (Rv) | +6.9[5] km/s |
| Proper motion (μ) | RA: –2.696[1] mas/yr Dec.: +15.802[1] mas/yr |
| Parallax (π) | 8.5862 ± 0.1086 mas[1] |
| Distance | 380 ± 5 ly (116 ± 1 pc) |
| Absolute magnitude (MV) | +0.236[6] |
| Details | |
| Mass | 2.59±0.14[3] M☉ |
| Radius | 1.7[7] R☉ |
| Luminosity | 70.6+19.4 −15.2[3] L☉ |
| Temperature | 9,078+169 −165[3] K |
| Rotational velocity (v sin i) | 65[3] km/s |
| Age | 970[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The visible component is an Ap star[3] with a stellar classification of A2Vs,[3] matching the evolutionary state of an A-type main sequence star while displaying "sharp" absorption lines. It is an estimated 970[6] million years old with a projected rotational velocity of 65 km/s.[3] The star has 2.6[3] times the mass of the Sun and around 1.7[7] times the Sun's radius. It is radiating 71[3] times the luminosity of the Sun from its photosphere at an effective temperature of 9,078 K.[3]
References
edit- ^ a b c d e 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.
- ^ a b c d Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J
- ^ a b c d e f g h i j k l Zorec, J.; et al. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy and Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
- ^ 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.
- ^ a b Wilson, Ralph Elmer (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication, Washington: Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.
- ^ a b c "HD 104538", WolframAlpha, retrieved 2012-08-05
- ^ a b 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): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
- ^ "6 Equ -- Star in double system", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-25.
- ^ Frankowski, A.; Jancart, S.; Jorissen, A. (March 2007), "Proper-motion binaries in the Hipparcos catalogue. Comparison with radial velocity data", Astronomy and Astrophysics, 464 (1): 377–392, arXiv:astro-ph/0612449, Bibcode:2007A&A...464..377F, doi:10.1051/0004-6361:20065526, S2CID 14010423
- ^ Mason, Brian D.; et al. (2001), "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.