A nursery of young objects:: Intergalactic HII regions in Stephan's quintet

We have discovered four intergalactic H II regions in Stephan's quintet, which is more than a 25 kpc projected distance from the center of the nearest group galaxy, with no apparent optical connection to it. They have M-B ranging from - 11.9 to - 12.5 mag, colors B-R = 0.7-1.1 mag, radial velocities from 6565 to 6651 km s(-1), and they are superposed onto the H I tail east of NGC 7319, with a mean radial velocity of 6610 km s(-1). In addition, they have metallicities of the order of 12+ log (O/H) = 8.58 +/- 0.25, which suggests that they were formed from preenriched material. We derive a mean age of 4.6 +/- 0.6 Myr and a mean stellar mass of (2.9 +/- 1.4) x 10(4) M-. for the four objects. The masses, ages, colors, velocities, metallicities, and location of the objects suggest that they are H II regions that were formed far away from the galaxies through compression of the intergalactic H I gas by galaxy collisions.