Delta1 Lyrae, its name Latinized from δ1 Lyrae, is a binary star system in the northern constellation of Lyra. It is dimly visible to the naked eye at night with a combined apparent visual magnitude of 5.56.[2] The system is located at a distance of approximately 1,160 light years from the Sun based on parallax,[1] but is drifting closer with a radial velocity of −26 km/s.[5] O. J. Eggen originally included this as a candidate member of the proposed Delta Lyrae cluster.[12]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Lyra |
| Right ascension | 18h 53m 43.55924s[1] |
| Declination | +36° 58′ 18.1891″[1] |
| Apparent magnitude (V) | 5.56[2] |
| Characteristics | |
| Spectral type | B2.5V[3][4] |
| U−B color index | −0.67[2] |
| B−V color index | −0.15[2] |
| Astrometry | |
| Radial velocity (Rv) | −25.8[5] km/s |
| Proper motion (μ) | RA: +1.350[1] mas/yr Dec.: −2.985[1] mas/yr |
| Parallax (π) | 2.8072 ± 0.1334 mas[1] |
| Distance | 1,160 ± 60 ly (360 ± 20 pc) |
| Absolute magnitude (MV) | −1.55[6] |
| Orbit[7] | |
| Period (P) | 88.352 days |
| Semi-major axis (a) | ≥46.8 Gm (0.313 AU) |
| Eccentricity (e) | 0.37±0.03 |
| Periastron epoch (T) | 2428406.613±0.500 JD |
| Argument of periastron (ω) (secondary) | 191.3±0.1° |
| Semi-amplitude (K1) (primary) | 39.7±1.8 km/s |
| Details | |
| δ1 Lyr A | |
| Mass | 7.9±0.1 M☉[4] 7.75±0.50 M☉[8] 6.6+0.68 −0.61[9] M☉ |
| Luminosity | 838[6] L☉ |
| Luminosity (bolometric) | 3,620[8] L☉ |
| Surface gravity (log g) | 3.764±0.032 (3.848 polar)[10] cgs |
| Temperature | 20,350[8] K |
| Metallicity [Fe/H] | −0.05[6] dex |
| Rotational velocity (v sin i) | 86±10[10] km/s |
| Age | 21.1±2.2 Myr[4] 9+9 −4[9] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The variable radial velocity of this star was discovered from photographic plates taken at the Yerkes Observatory in 1904.[13] The first set of orbital elements was computed by Frank Craig Jordan in 1916.[14] It is a single-lined spectroscopic binary with an orbital period of 88.4 days and an eccentricity (ovalness) of 0.37.[7]
The visible component of the pair has a blue-white hue with a stellar classification of B2.5V,[3][4] indicating that it is a B-type main-sequence star undergoing core hydrogen fusion. It is a few million years old with a relatively high rotation rate and around 7–8 times the mass of the Sun. The star is radiating about 3,620[8] times the Sun's luminosity from its photosphere at an effective temperature of 20,350 K.[8]
There is a magnitude 9.93 visual companion at an angular separation of 175.30 arcseconds along a position angle of 20°, as of 2012. This component was discovered by William Herschel.[15] It is an evolved giant star with a class of K2III at a distance of around 1,760 light years.[16]
References
edit- ^ a b c d e f 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 Guetter, H. H. (October 1974), "UBV photometry of 180 early-type stars", Publications of the Astronomical Society of the Pacific, 86: 795–797, Bibcode:1974PASP...86..795G, doi:10.1086/129675.
- ^ a b Guetter, Harry H. (April 1968), "Spectral classification of 239 early-type stars", Publications of the Astronomical Society of the Pacific, 80 (473): 197, Bibcode:1968PASP...80..197G, doi:10.1086/128611, S2CID 121565803.
- ^ a b c d Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873.
- ^ a b Wilson, Ralph Elmer (1953), "General catalogue of stellar radial velocities", Carnegie Institute Washington D.C. Publication, Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.
- ^ a b c 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.
- ^ a b Richardson, E. H.; McKellar, A. (1957), "Redetermination of the spectrographic orbit of delta1 Lyrae", Publ. Dominion Astrophys. Obs., 10: 407–413, Bibcode:1958PDAO...10..407R. , p. 412
- ^ a b c d e Hohle, M. M.; et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349, arXiv:1003.2335, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355, S2CID 111387483.
- ^ a b Gullikson, Kevin; et al. (July 26, 2016), "The Close Companion Mass-ratio Distribution of Intermediate-mass Stars", The Astronomical Journal, 152 (2): 40–53, arXiv:1604.06456, Bibcode:2016AJ....152...40G, doi:10.3847/0004-6256/152/2/40, S2CID 119179065.
- ^ a b Huang, W.; Gies, D. R. (August 2008), "Stellar Rotation in Field and Cluster B Stars", The Astrophysical Journal, 683 (2): 1045–1051, arXiv:0805.2133, Bibcode:2008ApJ...683.1045H, doi:10.1086/590106, S2CID 18926523.
- ^ "del01 Lyr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-01-23.
{{cite web}}: CS1 maint: postscript (link) - ^ Eggen, O. J. (July 1983), "Concentrations in the Local Association- II. The northern concentrations including the alf Per, Pleiades, M 34 and del LYR clusters.", Monthly Notices of the Royal Astronomical Society, 204: 391–403, Bibcode:1983MNRAS.204..391E, doi:10.1093/mnras/204.2.391.
- ^ Frost, E. B.; Adams, W. S. (1904), "Observations with the Bruce spectrograph", The Astrophysical Journal, 19: 352, Bibcode:1904ApJ....19..350F, doi:10.1086/141124.
- ^ Jordan, Frank Craig (1916), "The orbit of [delta]1 Lyrae", Publications of the Allegheny Observatory of the University of Pittsburgh, 3 (14): 119–124, Bibcode:1916PAllO...3..119J.
- ^ Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
- ^ "BD+36 3308". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-01-23.
{{cite web}}: CS1 maint: postscript (link)