HD 23128

UBV (RI)c standard stars in the E- and F-regions and in the Magellanic Clouds - a revised catalogue. Not Available
UBV(RI)c photometry of some standard sequences in the Harvard F regions and in the Magellanic Clouds Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1988MNRAS.231.1047M&db_key=AST
Standard Stars for VRI Photometry with S25 Response Photocathodes Not Available
Isolated Stroemgren spheres as a source of galactic H alpha emission The isolated H alpha emission features reported by Reynolds et al. areidentified with Stroemgren spheres surrounding observed O stars; theroot mean square electron densities and Stroemgren radii are calculatedfrom the observed emission measure and stellar type. The density has anaverage value of 2 per cu cm but increases to 3.3 per cu cm for starswithin 200 pc of the galactic plane. An analysis of the Catalogue ofGalactic O Stars shows that enhanced H alpha emission is observed aroundall known O stars. The diffuse component of H alpha emission is what onewould expect from the line-of-sight overlapping of isolated Stroemgrenspheres surrounding B stars and appears to correlate with features onextinction maps, as derived. There is no compelling reason to suggestany large-scale intercloud ionization from H alpha data alone.
Further observations of magnitude with a coarse grating Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1952MNRAS.112..665W&db_key=AST

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