Astronomy:R Lyrae

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Short description: Star in the constellation Lyra
Not to be confused with RR Lyrae.
R Lyrae
Location of 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
Evolutionary stage AGB[3]
Spectral type M5 III[4]
Apparent magnitude (J) −0.90[5]
U−B color index +1.41[5]
B−V color index +1.59[5]
Variable type SRb[2]
Astrometry
Radial velocity (Rv)−27.15[6] 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[4]
Details
Mass1.8±0.2[7] M☉
Radius195[7][lower-alpha 1] R☉
Luminosity4,130[7][lower-alpha 2] L☉
Surface gravity (log g)0.47[8] cgs
Temperature3,313[7] K
Other designations
Niandao, 13 Lyr, R Lyr, BD+43°3117, GC 25996, HD 175865, HIP 92862, HR 7157, SAO 47919, GSC 03131-02155
Database references
SIMBADdata

R Lyrae, also known by its Flamsteed designation 13 Lyrae and named Niandao,[9] 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.[10] It is one of the brightest stars at the K band, having an apparent magnitude of −2.08, only 14 stars are brighter.[11]

Visual band light curves for R Lyrae, adapted from Percy et al. (2001)[12]

In 1856, Joseph Baxendell announced that the star, then called 13 Lyrae, is a variable star.[13] In 1907 it appeared with its variable star designation, R Lyrae, in Annie Jump Cannon's Second Catalog of Variable Stars.[14] 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][15]

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☉.[7]

In Chinese astronomy, this star is part of the asterism Niǎn Dào (Imperial Passageway, 辇道). The IAU Working Group on Star Names adopted the name Niandao for this star on 18 June 2026.[9]

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. ↑ Baek, Hyeon; Cho, Se-Hyung; Kim, Jaeheon; Son, Seung-Min; Yoon, Dong-Hwan; Suh, Kyung-Won (2025). "Survey of Oxygen-rich AGB Stars Using the KVN 4 Receiving Bands—SMASTES. I.". The Astronomical Journal 170 (2): 84. doi:10.3847/1538-3881/ade1d1. Bibcode: 2025AJ....170...84B. 
  4. ↑ 4.0 4.1 4.2 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. 
  5. ↑ 5.0 5.1 5.2 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. 
  6. ↑ 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. 
  7. ↑ 7.0 7.1 7.2 7.3 7.4 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. 
  8. ↑ 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. 
  9. ↑ 9.0 9.1 "IAU Catalog of Star Names". https://exopla.net/star-names/modern-iau-star-names/. 
  10. ↑ 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. 
  11. ↑ Kmag < -2.08. SIMBAD.
  12. ↑ 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. 
  13. ↑ 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. 
  14. ↑ 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. 
  15. ↑ 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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