H I emission from Stephan's Quintet.

Neutral hydrogen emission profiles of two members of Stephan's Quintet, NGC 7320 and NGC 7319 (with redshifts of 744 and 6620 km 1, respectively) are presented. By requiring that the ratios MR IIMT and M /Lpg for these galaxies be normal for their classification, distances can be derived which are independent of the redshifts. These are 17(+ 17, - 8) Mpc for NGC 7320 and 47( t 55, -26) Mpc for NGC 7319. Although the uncertainties are large, the most probable distances derived in this fashion imply that these galaxies are unlikely to be physically related. The bulk of the uncertainty is not observational, but results from dispersions in the compiled integral properties of galaxies. Detection of a low-luminosity anonymous galaxy about 68' west of the Quintet, having a redshift of 886 km , further strengthens the contention that NOC 7320 is a member of a group which includes the large spiral NOC 7331 and which is at a distance of Mpc. Subject headings: galaxies, clusters of - 21-cm radiation