Antares & Rho Ophiuchi
- RA 16:30, Dec -25 (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.