Alpha Telescopii

Alpha Telescopii, at magnitude 3.51, is the brightest star in the modern constellation Telescopium, the Telescope.

Properties

The star is a blue-white class B3 IV subgiant with a surface temperature of 18,400 K. From 250 light years away, it shines with the luminosity of almost 900 suns. The star's luminosity and temperature indicate a mass of six suns, and strongly suggest that α Tel is a fairly young main-sequence star. Some 7 million years from now, it will evolve to a red giant, then lose its outer layers, and become a massive white dwarf like Sirius B.

α Tel is helium-rich, probably the result of a diffusion process. It is rotating slowly for a class B star, only 35 km/sec, suggesting that its pole is pointing more-or-less toward us. The star seems decidedly single, with no companion, although the Tycho catalog lists is as a possible intrinsic variable.

[Adapted from STARS by Jim Kaler, Professor Emeritus of Astronomy, University of Illinois]