R Lyrae

{{Short description|Star in the constellation Lyra}}

{{distinguish|RR Lyrae}}

{{Starbox begin

| name=R Lyrae

}}

{{Starbox image

| image=260px

| caption=R Lyrae (labelled as 13)

}}

{{Starbox observe

| epoch=J2000.0

| constell=Lyra

| ra={{RA|18|55|20.101223}}{{R:Van Leeuwen 2007 Validation of the new Hipparcos reduction}}

| dec={{DEC|+43|56|45.9215}}

| appmag_v=3.9 - 5.0{{cite web |title=GCVS Query=R Lyr |publisher=General Catalogue of Variable Stars @ Sternberg Astronomical Institute, Moscow, Russia |url=http://www.sai.msu.su/gcvs/cgi-bin/search.cgi?search=R+Lyr |accessdate=2012-08-22}}

}}

{{Starbox character

| class=M5 III

| appmag_1_passband = J

| appmag_1 = −0.90{{cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=CDS/ADC Collection of Electronic Catalogues|volume=2237|last1=Ducati|first1=J. R.|year=2002}}

| b-v=+1.59

| u-b=+1.41

| variable=SRb

}}

{{Starbox astrometry

| radial_v=−27.15{{cite journal|bibcode=2009A&A...498..627F|title=Spectroscopic binaries among Hipparcos M giants,. I. Data, orbits, and intrinsic variations|journal=Astronomy and Astrophysics|volume=498|issue=2|pages=627|last1=Famaey|first1=B.|last2=Pourbaix|first2=D.|last3=Frankowski|first3=A.|last4=Van Eck|first4=S.|last5=Mayor|first5=M.|last6=Udry|first6=S.|last7=Jorissen|first7=A.|year=2009|doi=10.1051/0004-6361/200810698|arxiv = 0901.0934 |s2cid=18739721}}

| prop_mo_ra=21.05

| prop_mo_dec=82.06

| parallax=10.94

| p_error=0.12

| parallax_footnote=

| absmag_v=−1.1{{cite journal|bibcode=2004MNRAS.355..601Y|title=Period-luminosity relation for M-type semiregular variables from Hipparcos parallaxes|journal=Monthly Notices of the Royal Astronomical Society|volume=355|issue=2|pages=601|last1=Yeşilyaprak|first1=C.|last2=Aslan|first2=Z.|year=2004|doi=10.1111/j.1365-2966.2004.08344.x|doi-access=free}}

}}

{{Starbox detail

| mass = {{val|1.8|0.2}}

| radius = {{solar radius calculator|type=LT|4130|3313}}{{efn | name=radius | Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772 K:

:$\backslash sqrt\{\backslash biggl(\backslash frac\{5,772\}\{3,313\}\backslash biggr)^4\; \backslash cdot\; 4,130\}\; =\; 195\backslash \; R\_\backslash odot$.}}

| luminosity = 4,130{{efn|1=Calculated using the absolute bolometric magnitude of R lyrae, with respect to the Sun's absolute bolometric magnitude of 4.83:
10{{sup|0.4(4.74+(−4.3)}} = 4130.48.}}

| temperature = 3,313{{cite journal|bibcode=2015MNRAS.451.2957H|arxiv=1507.01517|title=Exploring masses and CNO surface abundances of red giant stars|journal=Monthly Notices of the Royal Astronomical Society|volume=451|issue=3|pages=2957|last1=Halabi|first1=Ghina M.|last2=Eid|first2=Mounib El|year=2015|doi=10.1093/mnras/stv1141|doi-access=free |s2cid=118707332}}

| metallicity_fe = −0.29

| gravity = 0.47{{cite journal|bibcode= 2011A&A...531A.165P|title= The atmospheric parameters and spectral interpolator for the MILES stars|journal= Astronomy & Astrophysics|volume= 531|pages= A165|last1= Prugniel|first1= Ph.|last2= Vauglin|first2= I.|last3= Koleva|first3= M.|year= 2011|doi= 10.1051/0004-6361/201116769|arxiv = 1104.4952 |s2cid= 54940439}}

| rotational_velocity =

| age =

}}

{{Starbox catalog

| names=R Lyrae, 13 Lyrae, HR 7157, BD+43°3117, HD 175865, SAO 47919, HIP 92862, GC 25996, GSC 03131-02155

}}

{{Starbox reference

|Simbad=13+Lyrae

}}

{{Starbox end}}

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.{{cite journal|author1=Jiménez-Esteban, F. M. |author2=Caballero, J. A. |author3=Dorda, R. |author4=Miles-Páez, P. A. |author5=Solano, E. |date=2012|title=Identification of red high proper-motion objects in Tycho-2 and 2MASS catalogues using Virtual Observatory tools|journal=Astronomy & Astrophysics|volume=539|pages=12|doi=10.1051/0004-6361/201118375 |bibcode=2012A&A...539A..86J|arxiv = 1201.5315 |s2cid=53404166 }} It is one of the brightest stars at the K band, having an apparent magnitude of −2.08, only 14 stars are brighter.[https://simbad.cds.unistra.fr/simbad/sim-sam?Criteria=Kmag+%3C+-2.08&submit=submit+query&OutputMode=LIST&maxObject=10000&CriteriaFile= Kmag < -2.08]. SIMBAD.

File:RLyrLightCurve.png 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. 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.{{cite journal|bibcode=2007MNRAS.378.1543G|arxiv=0704.3150|title=Semiregular variables in the solar neighbourhood|journal=Monthly Notices of the Royal Astronomical Society|volume=378|issue=4|pages=1543–1549|last1=Glass|first1=I. S.|last2=Van Leeuwen|first2=F.|year=2007|doi=10.1111/j.1365-2966.2007.11903.x|doi-access=free |s2cid=14332208}}

It is calculated that R Lyrae was a {{solar mass|2.0}} 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 {{solar mass|1.8}}.