Revealing deuterium Balmer lines in HII regions with VLT-UVES

Abstract

The search for deuterium Balmer lines with VLT-UVES is reported in HII regions of the Galaxy and the Magellanic Clouds. The DI lines appear as faint, narrow emission features in the blue wings of the HI Balmer lines and can be distinguished from high-velocity HI emission. The previous identification to deuterium is re-inforced beyond doubt. The detection of D-alpha and D-beta in Orion (Hebrard et al. 2000) is confirmed and deuterium lines are now detected up to at least D-eta. The UVES observations provide the first detection of Balmer DI lines in four new HII regions (M 8, M 16, M 20, and DEM S 103 in SMC), demonstrating that these lines are of common occurence.