Theta Lyrae
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Lyra |
| Right ascension | 19h 16m 22.0951s / 19h 16m 30.069s / 19h 16m 28.7s |
| Declination | +38° 8' 1.431" / +38° 8' 35.80" / +38° 7' 1" |
| Apparent magnitude (V) | 4.347 / 9.5 / 11.0 |
| Characteristics | |
| Spectral type | K0II[1] + K2III + ? |
| U−B color index | +1.23[citation needed] |
| B−V color index | +1.25[citation needed] |
| Astrometry | |
| Radial velocity (Rv) | −31.05±0.14[2] km/s |
| Proper motion (μ) | RA: −2.864 mas/yr[2] Dec.: 4.114 mas/yr[2] |
| Parallax (π) | 4.2005 ± 0.1053 mas[2] |
| Distance | 755.6+21.8 −20.2 ly (237.9+6.7 −6.2 pc)[3] |
| Absolute magnitude (MV) | −2.76+0.27 −0.24[1] |
| Details | |
| θ Lyr | |
| Radius | 60.31+1.92 −2.99[4] R☉ |
| Luminosity | 1,374±43[4] L☉ |
| Surface gravity (log g) | 1.93[1] cgs |
| Temperature | 4,523±44[4] K |
| Metallicity [Fe/H] | −0.01[1] dex |
| Rotational velocity (v sin i) | 3.6±1.4[1] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Theta Lyrae (θ Lyr) is a star in a trinary star system, in the constellation Lyra, approximately 760 light years away from Earth. Theta Lyrae is an orange bright giant star of the spectral type K0II, which means that it possesses a surface temperature of about 5,000 K, and is many times bigger and brighter, yet cooler, than the Sun.
It is orbited by a subsystem composed of BD+37° 3399 and BD+37° 3399B. 10th magnitude BD+37° 3399 is a giant star with a spectral type of K2III. It is therefore almost the same temperature as Theta Lyrae, but smaller and dimmer.[6] BD+37° 3399B is an 11th magnitude star of an unknown spectral type.[7]
References
[edit]- ^ a b c d e Carney, Bruce W.; et al. (March 2008), "Rotation and Macroturbulence in Metal-Poor Field Red Giant and Red Horizontal Branch Stars", The Astronomical Journal, 135 (3): 892–906, arXiv:0711.4984, Bibcode:2008AJ....135..892C, doi:10.1088/0004-6256/135/3/892, S2CID 2756572
- ^ a b c Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ Bailer-Jones, C. A. L.; Rybizki, J.; Fouesneau, M.; Demleitner, M.; Andrae, R. (2021). "Estimating Distances from Parallaxes. V. Geometric and Photogeometric Distances to 1.47 Billion Stars in Gaia Early Data Release 3". The Astronomical Journal. 161 (3): 147. arXiv:2012.05220. Bibcode:2021AJ....161..147B. doi:10.3847/1538-3881/abd806. S2CID 228063812. Data about this star can be seen here.
- ^ a b c Baines, Ellyn K.; Clark, James H., III; Schmitt, Henrique R.; Stone, Jordan M.; von Braun, Kaspar (2023-12-01). "33 New Stellar Angular Diameters from the NPOI, and Nearly 180 NPOI Diameters as an Ensemble". The Astronomical Journal. 166 (6): 268. Bibcode:2023AJ....166..268B. doi:10.3847/1538-3881/ad08be. ISSN 0004-6256.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ "* tet Lyr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 15, 2007.
- ^ a b "BD+37 3399". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 15, 2007.
- ^ a b "Simbad Query Result". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 15, 2007.