Astronomy:R Lyrae

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Short description: Star in the constellation Lyra
Not to be confused with RR Lyrae.
R Lyrae
260px
R Lyrae (labelled as 13)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Lyra
Right ascension  18h 55m 20.101223s[1]
Declination +43° 56′ 45.9215″[1]
Apparent magnitude (V) 3.9 - 5.0[2]
Characteristics
Spectral type M5 III[3]
Apparent magnitude (J) −0.90[4]
U−B color index +1.41[4]
B−V color index +1.59[4]
Variable type SRb[2]
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[1] mas
Distance298 ± 3 ly
(91 ± 1 pc)
Absolute magnitude (MV)−1.1[3]
Details
Mass1.8±0.2[6] M☉
Radius195[6][lower-alpha 1] R☉
Luminosity4,130[6][lower-alpha 2] L☉
Surface gravity (log g)0.47[7] cgs
Temperature3,313[6] 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
SIMBADdata

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.[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]

Visual band light curves for R Lyrae, adapted from Percy et al. (2001)[10]

In 1856, Joseph Baxendell announced that the star, then called 13 Lyrae, is a variable star.[11] In 1907 it appeared with its variable star designation, R Lyrae, in Annie Jump Cannon's Second Catalog of Variable Stars.[12] 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.[3][13]

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☉.[6]

Notes

  1. ↑ Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772 K:
    (5,7723,313)4⋅4,130=195 R⊙.
  2. ↑ 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

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Van Leeuwen, Floor (2007). "Validation of the new Hipparcos reduction". Astronomy & Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V. 
  2. ↑ 2.0 2.1 "GCVS Query=R Lyr". General Catalogue of Variable Stars @ Sternberg Astronomical Institute, Moscow, Russia. http://www.sai.msu.su/gcvs/cgi-bin/search.cgi?search=R+Lyr. Retrieved 2012-08-22. 
  3. ↑ 3.0 3.1 3.2 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. doi:10.1111/j.1365-2966.2004.08344.x. Bibcode: 2004MNRAS.355..601Y. 
  4. ↑ 4.0 4.1 4.2 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. 
  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. doi:10.1051/0004-6361/200810698. Bibcode: 2009A&A...498..627F. 
  6. ↑ 6.0 6.1 6.2 6.3 6.4 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. doi:10.1093/mnras/stv1141. Bibcode: 2015MNRAS.451.2957H. 
  7. ↑ Prugniel, Ph.; Vauglin, I.; Koleva, M. (2011). "The atmospheric parameters and spectral interpolator for the MILES stars". Astronomy & Astrophysics 531: A165. doi:10.1051/0004-6361/201116769. Bibcode: 2011A&A...531A.165P. 
  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. doi:10.1051/0004-6361/201118375. Bibcode: 2012A&A...539A..86J. 
  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. doi:10.1086/322153. Bibcode: 2001PASP..113..983P. 
  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. https://articles.adsabs.harvard.edu/pdf/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. https://articles.adsabs.harvard.edu/pdf/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. doi:10.1111/j.1365-2966.2007.11903.x. Bibcode: 2007MNRAS.378.1543G. 



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