R Lyrae (13 Lyrae) -- Red Giant Semiregular Variable Star in Lyra
R Lyrae -- Reddish Star in Northern Lyra
The color of R Lyrae (13 Lyrae) stands out boldly in the eyepiece against the black sky and dimmer
white surrounding stars. This Red Giant is a semiregular variable that has produced several
periodical brightness curves over the last hundred years and thus it is hard to predict how bright it
is going to be when one views it. Both hydrogen and helium shells within the star are providing
energy to R Lyrae (only hydrogen fuses in our sun). With just twice the mass of our sun it is
radiating over 4,000 times the light.
More likely than not, R Lyrae is stumbled on by accident by amateurs sweeping the background
stars north of Vega. It is its color that makes it stand out. I would recommend not waiting to find
this colorful star by accident but by going directly to it with your telescope and for a few minutes
absorbing its reddish hue.