T Lyrae -- Carbon Star in Lyra
Big Red
When it comes to strange stars, it is hard to beat T Lyrae. First, it is big, it would easily
engulf Earth and Mars if placed at our sun’s location. Its energy output (luminosity) is
staggering -- radiating 15,000 times as much as our sun (most in infrared). Not bad for a
star that has only three-times the mass of our sun. In addition, T Lyrae pulsates on an
irregular period averaging a cycle every 0.5 days. Its brightness varies by almost 2
magnitudes.
When you first point a telescope to it, none of these facts can be noticed, what makes it
standout is its dark blood-red color. T Lyrae is a rare Carbon Star. Carbon Stars are
unique in that their atmospheres contain more carbon than oxygen – not so in other stars.
The carbon combines with the oxygen, forming carbon monoxide, which consumes all the
available oxygen in the star’s upper atmosphere. The leftover carbon atoms bond with
other elements causing the star to shine ruby-red in color. No stars are darker-red than
Carbon Stars.
T Lyrae is an easy star hop from the fifth brightest star in the heavens, Vega. Its blood
red-color stands out, so you are not going to just accidentally slew over it without seeing it.
Once you find it, I guarantee that you will return to it over and over again.