Iota Lyrae
ι Lyrae, Latinised as Iota Lyrae, is a binary star[2] in the northern constellation of Lyra. It is visible to the naked eye as a dim, blue-white hued star with an apparent visual magnitude that fluctuates around 5.22.[2] This object is located approximately 950 light years distant from the Sun based on parallax, but is drifting nearer with a radial velocity of −26 km/s.[5]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Lyra |
| Right ascension | 19h 07m 18.13251s[1] |
| Declination | +36° 06′ 00.5592″[1] |
| Apparent magnitude (V) | 5.22[2] |
| Characteristics | |
| Spectral type | B6IV[3] |
| Variable type | Be star[4] |
| Astrometry | |
| Radial velocity (Rv) | −26.0±4.6[5] km/s |
| Proper motion (μ) | RA: −1.04±0.16[6] mas/yr Dec.: −4.29±0.20[6] mas/yr |
| Parallax (π) | 3.5858 ± 0.1924[1] mas |
| Distance | 910 ± 50 ly (280 ± 10 pc) |
| Absolute magnitude (MV) | −1.94[7] |
| Orbit[8] | |
| Period (P) | 216.93 yr |
| Semi-major axis (a) | 0.172″ |
| Eccentricity (e) | 0.637 |
| Inclination (i) | 145.5° |
| Longitude of the node (Ω) | 171.4° |
| Periastron epoch (T) | B 1997.28 |
| Argument of periastron (ω) (secondary) | 201.2° |
| Details | |
| Mass | 5.02±0.09[9] M☉ |
| Luminosity | 1,349+175 −155[9] L☉ |
| Temperature | 13,428+124 −123[9] K |
| Rotational velocity (v sin i) | 224[9] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a wide binary system with a computed orbital period of 217 years and an eccentricity of 0.6.[8] The primary component has a stellar classification of B6IV,[3] matching a B-type subgiant star. It is a Be star,[11] displaying emission lines in its spectrum, and is spinning rapidly with a projected rotational velocity of 224 km/s.[9] The star ranges in brightness from magnitude 5.20 down to 5.27.[4] It has five[9] times the mass of the Sun and is radiating 1,349[9] times the Sun's luminosity from its photosphere at an effective temperature of 13,428 K.[9]
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.
- Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x.
- 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.
- Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S.
- 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.
- 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.
- 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.
- "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Retrieved 15 March 2017.
- 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.
- "iot Lyr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-04.
- Abt, H. A.; Cardona, O. (October 1984), "Be stars in binaries", Astrophysical Journal, 285: 190–194, Bibcode:1984ApJ...285..190A, doi:10.1086/162490