(Scorpio/Ophiuchus) Type: emission / reflection nebulae Distance: Antares - 520 ly; M 4 - 7500 ly The star in the yellow region is Antares (Alpha Scorpii); the star in the blue region at the right is Rho Ophiuchi surrounded by the emission nebula IC 4604; the star in the red region at the bottom is Sigma Scorpii; just below Antares is the globular cluster M 4. The bright region just to the left of Rho Ophiuchi shows evidence of new star formation. Antares (aka "Le Coeur de Scorpion" -- the Heart of the Scorpion) is a red supergiant star some 700 times larger in diameter than the Sun, though it is "only" 9000 times more luminous and "only" 10 or 15 times more massive. Note that M 4 is much more distant than the Antares/Rho Ophiuchi nebulosity; we see it thru the intervening gasses. |