Interstellar dust and distances to planetary nebulae.
Abstract
UBV and Hy data are used to construct diagrams of color excess versus distance for early-type stars within 1 5 of six planetary nebulae. These diagrams are used in conjunction with the observed extinctions of the planetaries to derive distances for NGC 6741, NOC 6894, NGC 7026, NGC 7354, IC 1747, and IC 289. This method is independent of assumptions about optical thickness in the nebular shell or evolutionary stage. Assumptions of electron temperature and R, the ratio of total to selective absorption, are required. The method is limited in accuracy by the patchiness of the interstellar medium and by the possibility that R may vary from point to point in the Galaxy. Subject headings: early-type stars - interstellar reddening - photometry - planetary nebulae
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1973
- DOI:
- 10.1086/152036
- Bibcode:
- 1973ApJ...181..135L