Spectroscopy of the interstellar medium in the Magellanic Bridge
Abstract
Our optical observations of two B-type stars in the Magellanic Bridge, a region of material between the Large and Small Magellanic Clouds {LMC, SMC}, reveal strong interstellar Ca II K absorption arising from the Bridge gas. We now propose to obtain medium resolution STIS spectra of the ultraviolet interstellar lines toward both of the stars. The proposed observations will provide an opportunity to investigate the physical conditions within the Bridge gas, and to determine the chemical composition of important elements such as C, N, O, Mg, Si, S, and Fe. These abundances will be compared with those found for the LMC and SMC, which will allow us to investigate if the Bridge gas originated in the SMC, as current theory suggests. The presence of young B-type stars in the Bridge implies that star formation is still occurring in this region. It has been suggested that the formation mechanism is similar to that believed to be responsible for some of the young B-type stars found in the halo of our Galaxy, namely collisions between cloudlets within high-velocity clouds {HVCs}. To investigate this, we will compare our derived physical conditions for the Bridge gas with those found for halo HVCs. We will also search for cloudlet structure in the Bridge gas, through the identification of multicomponents in the interstellar line profiles; such cloudlets have already been found by us in an HVC.
- Publication:
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HST Proposal
- Pub Date:
- July 1997
- Bibcode:
- 1997hst..prop.7511K