This image of the supergiant star Betelgeuse was taken by the ESO’s Very Large Telescope. Even looking through the Earth’s turbulent atmosphere, the resolution is as fine as 37 milliarcseconds. (An arcsecond is 1/3600 of a degree. A milliarcsecond is 1/1000 arcsecond.) That’s roughly the same as being able to see a tennis ball on the ground from the International Space Station.
Image Credit: ESO and P. Kervella
“Betelgeuse, Betelgeuse, Betelgeuse!”
Distance (from Hipparcos satellite) – 440 light years
Visual absolute magnitude -5.14
Visual Luminosity 9700 X Sun
Bolometric Luminosity ~ 65000 X Sun
Diameter – 600 X Sun
Mass ~ 12 X Sun?
Type Spectrum = M2 Ib
Of the 21 brightest stars in the sky, 5 are supergiants:
Antares (M1 Ib); Betelgeuse (M2 Ib); Canopus (F0 Ib); Rigel (B8 Iab);
Deneb (A2 Ia). Canopus is the nearest supergiant at 310 light years;
Deneb the most distant at 3000 lears. Deneb has a visual luminosity
of 300000X Sun.
Correction on Deneb that should be 265000 X Sun.
Canopus, the nearest supergiant, is 14000 X Sun.
Supergiant stars are supernovae waiting to happen–you don’t want one
too close to you because when it blows it will shower the Earth with lethal
cosmic radiation.