W. J. Maciel - Abstract #59NEW KINEMATIC DISTANCES OF NGC 7009 AND BD+303639 FROM UV AND RADIO DATAW. J. Maciel Astrophys. Space Sci. 229, 203-213 (1995) Measurements of the equivalent width of the interstellar Lyman alpha line from IUE spectra in the direction of the planetary nebulae NGC 7009 and BD+303639 are used to infer the H column density in these directions. Hydrogen 21 cm profiles are also used in connection with the ultraviolet data so that the expected rotation velocities and distances can be determined. The results are compared with recently published distances, in an attempt to distinguish between the "short" and "long" PN distance scales as applied to these objects. |