Selective Absorption Near the North Pole and the Spectrum-Colour Relation
Discussion of spectral types and colour indices (Mount Wilson Polar Catalogue ) for about iooo stars north of +80° declination gives (1) the magnitude error in C , (2) a revised spectrum-colour relation, (3) the mean colour excess as a function of distance. The magnitude error, which affects stars b...
| Published in: | Monthly Notices of the Royal Astronomical Society |
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| Main Author: | |
| Format: | Text |
| Language: | English |
| Published: |
Oxford University Press
1944
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| Subjects: | |
| Online Access: | http://mnras.oxfordjournals.org/cgi/content/short/103/6/281 https://doi.org/10.1093/mnras/103.6.281 |
| Summary: | Discussion of spectral types and colour indices (Mount Wilson Polar Catalogue ) for about iooo stars north of +80° declination gives (1) the magnitude error in C , (2) a revised spectrum-colour relation, (3) the mean colour excess as a function of distance. The magnitude error, which affects stars brighter than Pυ m 9.2 of types earlier than Go, accounts for the contradictions in the selective absorption and in the colour of Ao stars found by E. G. Martin. For Ao the absorption-free value is C = −0.15 mag. The obscuring cloud, which apparently extends to about 450 parsecs, produces a maximum colour excess of 0.27 mag. (international system). |
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