R Lyrae

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Not to be confused with RR Lyrae.
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) 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[1] mas
Distance 298 ± 3 ly
(91 ± 1 pc)
Absolute magnitude (MV) −1.1[4]
Details
Mass 1.80[6] M
Luminosity 4,168[6] 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 near Vega

R 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]

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][9]

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]

References[edit]

  1. ^ a b c d e Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752Freely accessible. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. 
  2. ^ 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. 
  3. ^ a b "GCVS Query=R Lyr". General Catalogue of Variable Stars @ Sternberg Astronomical Institute, Moscow, Russia. Retrieved 2012-08-22. 
  4. ^ 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. 
  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:0901.0934Freely accessible. Bibcode:2009A&A...498..627F. doi:10.1051/0004-6361/200810698. 
  6. ^ a b c d 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:1507.01517Freely accessible. Bibcode:2015MNRAS.451.2957H. doi:10.1093/mnras/stv1141. 
  7. ^ Prugniel, Ph.; Vauglin, I.; Koleva, M. (2011). "The atmospheric parameters and spectral interpolator for the MILES stars". Astronomy & Astrophysics. 531: A165. arXiv:1104.4952Freely accessible. Bibcode:2011A&A...531A.165P. doi:10.1051/0004-6361/201116769. 
  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:1201.5315Freely accessible. Bibcode:2012A&A...539A..86J. doi:10.1051/0004-6361/201118375. 
  9. ^ Glass, I. S.; Van Leeuwen, F. (2007). "Semiregular variables in the solar neighbourhood". Monthly Notices of the Royal Astronomical Society. 378 (4): 1543. arXiv:0704.3150Freely accessible. Bibcode:2007MNRAS.378.1543G. doi:10.1111/j.1365-2966.2007.11903.x.