R Lyrae

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R Lyrae
Lyra constellation map.svg
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)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  mas [1]
Distance 298 ± 3  ly
(91 ± 1  pc)
Absolute magnitude  (MV)−1.1 [3]
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
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. [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) RLyrLightCurve.png
Visual band light curves for R Lyrae, adapted from Percy et al. (2001)

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:
    .
  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 2 3 4 5 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. 1 2 "GCVS Query=R Lyr". General Catalogue of Variable Stars @ Sternberg Astronomical Institute, Moscow, Russia . Retrieved 2012-08-22.
  3. 1 2 3 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 .
  4. 1 2 3 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. arXiv: 0901.0934 . Bibcode:2009A&A...498..627F. doi:10.1051/0004-6361/200810698. S2CID   18739721.
  6. 1 2 3 4 5 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.
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