R Lyrae
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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.[1] It is one of the brightest stars at the K band, having an apparent magnitude of −2.08, only 14 stars are brighter.[2]
In 1856, Joseph Baxendell announced that the star, then called 13 Lyrae, is a variable star.[4] In 1907 it appeared with its variable star designation, R Lyrae, in Annie Jump Cannon's Second Catalog of Variable Stars.[5] 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.[6][7]
It is calculated that R Lyrae was a Template:Solar mass 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 Template:Solar mass.[8]
Notes
References
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- ↑ Kmag < -2.08. SIMBAD.
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