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R Lyrae

R Lyrae (labelled as 13)
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Lyra
Right ascension	18 55 20.101223
Declination	+43° 56′ 45.9215″
Apparent magnitude (V)	4.00 (3.9 - 5.0)
Characteristics
Spectral type	M5 III
Apparent magnitude (J)	−0.90
U−B color index	+1.41
B−V color index	+1.59
Variable type	SRb
Astrometry
Radial velocity (Rv)	−27.15 km/s
Proper motion (μ)	RA: 21.05 mas/yr Dec.: 82.06 mas/yr
Parallax (π)	10.94 ± 0.12 mas
Distance	298 ± 3 ly (91 ± 1 pc)
Absolute magnitude (MV)	−1.1
Details
Mass	1.8±0.2 M☉
Radius	195 R☉
Luminosity	4,130 L☉
Surface gravity (log g)	0.47 cgs
Temperature	3,313 K
Other designations
R Lyrae, 13 Lyrae, HR 7157, BD+43°3117, HD 175865, SAO 47919, HIP 92862, GC 25996, GSC 03131-02155
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 visible to the naked eye. It is a red giant star of the spectral type M5III, currently at the last stages of evolution. 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. It is one of the brightest stars at the K band, having an apparent magnitude of −2.08, only 14 stars are brighter.

In 1856, Joseph Baxendell announced that the star, then called 13 Lyrae, is a variable star. In 1907 it appeared with its variable star designation, R Lyrae, in Annie Jump Cannon's Second Catalog of Variable Stars. 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.

It is calculated that R Lyrae was a 2.0 M_☉ star on the main sequence, similar to Sirius A today. It is now an oxygen-rich asymptotic giant branch star, with both hydrogen and helium shells fusing. Due to stellar mass loss, R Lyrae now has a mass of 1.8 M_☉.

Notes

1. Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772 K:

   ${\displaystyle {\sqrt {{\biggl (}{\frac {5,772}{3,313}}{\biggr )}^{4}\cdot 4,130}}=195\ R_{\odot }}$.

2. Calculated using the absolute bolometric magnitude of R lyrae, with respect to the Sun's absolute bolometric magnitude of 4.83:
   10 = 4130.48.

References

1. ^ 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.
2. ^ 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.
3. ^ "GCVS Query=R Lyr". General Catalogue of Variable Stars @ Sternberg Astronomical Institute, Moscow, Russia. Retrieved 2012-08-22.
4. ^ 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.
5. 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.
6. ^ 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.
7. 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.
8. 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.
9. Kmag < -2.08. SIMBAD.
10. 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.
11. Baxendell, Joshua (sic) (June 1856). "On the Variability of 13 Lyræ". Monthly Notices of the Royal Astronomical Society. 16: 201. Bibcode:1856MNRAS..16Q.201B. Retrieved 16 December 2024.
12. Cannon, Annie J. (1907). "Second catalogue of variable stars". Annals of Harvard College Observatory. 55: 1–94. Bibcode:1907AnHar..55....1C. Retrieved 16 December 2024.
13. 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.

• Lyra
• Flamsteed objects
• Objects with variable star designations
• Semiregular variable stars
• Bright Star Catalogue objects
• Henry Draper Catalogue objects
• Hipparcos objects
• Durchmusterung objects
• M-type giants