 R Lyrae (labelled as 13) | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Lyra |
| Right ascension | 18h 55m 20.101223s [1] |
| Declination | +43° 56′ 45.9215″ [1] |
| Apparent magnitude (V) | 4.00 [2] (3.9 - 5.0 [3]) |
| Characteristics | |
| Spectral type | M5 III [4] |
| Apparent magnitude ( J) | −0.90 [2] |
| U−B color index | +1.41 [2] |
| B−V color index | +1.59 [2] |
| Variable type | SRb [3] |
| Astrometry | |
| Radial velocity (Rv) | −27.15 [5] km/s |
| Proper motion (μ) |
RA: 21.05
[1]
mas/
yr Dec.: 82.06 [1] mas/ yr |
| Parallax (π) | 10.94 ± 0.12 mas [1] |
| Distance | 298 ± 3
ly (91 ± 1 pc) |
| Absolute magnitude (MV) | −1.1 [4] |
| Details | |
| Mass | 1.8±0.2 [6] M☉ |
| Radius | 195 [6] [a] R☉ |
| Luminosity | 4,130 [6] [b] L☉ |
| Surface gravity (log g) | 0.47 [7] cgs |
| Temperature | 3,313 [6] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
R Lyrae, also known as its Flamsteed designation 13 Lyrae, is a 4th magnitude semiregular variable star in the constellation Lyra, approximately 350 light years away from Earth. It is a red giant star of the spectral type M5III, meaning it has a surface temperature of under 3,500 kelvins. It is much larger and brighter, yet cooler, than the Sun. In the near- infrared J band, it is brighter than the nearby Vega.
R Lyrae is unusual in that it is a red star with a high proper motion, greater than 50 milliarcseconds a year. [8] It is one of the brightest stars at the K band, having an apparent magnitude of −2.08, only 14 stars are brighter. [9]
The variability is not consistent and regular, but periods of 46, 64, 378, and 1,000 days have been reported, with the 46-day period being the strongest. [4] [11]
It is calculated that R Lyrae was a 2.0 M☉ star on the main sequence. It is considered an oxygen-rich asymptotic giant branch star, with both hydrogen and helium shells fusing. [6]
Notes
-
^ Applying the
Stefan–Boltzmann law with a nominal
solar
effective temperature of 5,772
K:
- .
-
^ Calculated using the
absolute bolometric magnitude of R lyrae, with respect to the Sun's absolute bolometric magnitude of 4.83:
100.4(4.74+(−4.3) = 4130.48.
References
- ^ a b c d e van Leeuwen, Floor (13 August 2007). "Validation of the new Hipparcos reduction". Astronomy & Astrophysics. 474 (2): 653–664. arXiv: 0708.1752. Bibcode: 2007A&A...474..653V. doi: 10.1051/0004-6361:20078357. eISSN 1432-0746. ISSN 0004-6361.
- ^ a b c d Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode: 2002yCat.2237....0D.
- ^ a b "GCVS Query=R Lyr". General Catalogue of Variable Stars @ Sternberg Astronomical Institute, Moscow, Russia. Retrieved 2012-08-22.
- ^ a b c Yeşilyaprak, C.; Aslan, Z. (2004). "Period-luminosity relation for M-type semiregular variables from Hipparcos parallaxes". Monthly Notices of the Royal Astronomical Society. 355 (2): 601. Bibcode: 2004MNRAS.355..601Y. doi: 10.1111/j.1365-2966.2004.08344.x.
- ^ Famaey, B.; Pourbaix, D.; Frankowski, A.; Van Eck, S.; Mayor, M.; Udry, S.; Jorissen, A. (2009). "Spectroscopic binaries among Hipparcos M giants,. I. Data, orbits, and intrinsic variations". Astronomy and Astrophysics. 498 (2): 627. arXiv: 0901.0934. Bibcode: 2009A&A...498..627F. doi: 10.1051/0004-6361/200810698. S2CID 18739721.
- ^ a b c d e Halabi, Ghina M.; Eid, Mounib El (2015). "Exploring masses and CNO surface abundances of red giant stars". Monthly Notices of the Royal Astronomical Society. 451 (3): 2957. arXiv: 1507.01517. Bibcode: 2015MNRAS.451.2957H. doi: 10.1093/mnras/stv1141. S2CID 118707332.
- ^ Prugniel, Ph.; Vauglin, I.; Koleva, M. (2011). "The atmospheric parameters and spectral interpolator for the MILES stars". Astronomy & Astrophysics. 531: A165. arXiv: 1104.4952. Bibcode: 2011A&A...531A.165P. doi: 10.1051/0004-6361/201116769. S2CID 54940439.
- ^ Jiménez-Esteban, F. M.; Caballero, J. A.; Dorda, R.; Miles-Páez, P. A.; Solano, E. (2012). "Identification of red high proper-motion objects in Tycho-2 and 2MASS catalogues using Virtual Observatory tools". Astronomy & Astrophysics. 539: 12. arXiv: 1201.5315. Bibcode: 2012A&A...539A..86J. doi: 10.1051/0004-6361/201118375. S2CID 53404166.
- ^ Kmag < -2.08. SIMBAD.
- ^ Percy, John R.; Wilson, Joseph B.; Henry, Gregory W. (August 2001). "Long-Term VRI Photometry of Small-Amplitude Red Variables. I. Light Curves and Periods". Publications of the Astronomical Society of the Pacific. 113 (786): 983–996. Bibcode: 2001PASP..113..983P. doi: 10.1086/322153. S2CID 14609175.
- ^ Glass, I. S.; Van Leeuwen, F. (2007). "Semiregular variables in the solar neighbourhood". Monthly Notices of the Royal Astronomical Society. 378 (4): 1543–1549. arXiv: 0704.3150. Bibcode: 2007MNRAS.378.1543G. doi: 10.1111/j.1365-2966.2007.11903.x. S2CID 14332208.