Spectral types in the direction of the Magellanic Stream

Abstract

Deep hypersensitized UKSTU objective-prism plates have been used in a search for faint blue spectra belonging to early-type stars in the direction of the Magellanic Stream. The two regions studied here are coincident with the small dense neutral-hydrogen condensations near the northern tip of the Stream studied by Mirabel et al. (1979). Unwidened spectra in these regions were visually inspected and classified and the results analysed, in the hope of detecting large numbers of early-type stars at faint magnitudes which might belong to the Magellanic Stream. From apparent magnitude and spectral type estimates, we conclude that the number of early A-type stars found per square degree is almost a factor of 10 lower than what we should expect if the Stream originated out of a tidal stripping by gravitational interaction between one of the Magellanic Clouds and our own Galaxy some |$2\,\times\,{10}^{8}$| yr ago. Furthermore, the absence of such a stellar component is discussed in terms of the assumed distance to the Magellanic Stream.