The Antares-Rho Ophiuchi Region

Antares (lower middle) is a red supergiant 10,000 times brighter than the sun. Its radius is almost four times the sun-earth distance. The glow surrounding Antares is from the star ejecting part of its mass in a fierce steady stellar wind. On the lower right is the globular star cluster M4. It is 7,000 light years away and contains hundreds of thousands of stars. Near the top is Rho Ophiuchi, a quadruple star which energies a blue reflection nebula. Red glow in the region is primarily from excited hydrogen gas. Intervening dark dust lanes add additional complexity to the image.