Distribution of the interstellar grains.
For 40 cepheids in Ι=60~215°, there exists fairly strong correlation between colour excesses and quantities of neutral hydrogen atoms, suggesting that the interstellar grains and the neutral hydrogen atoms may coexist. In wider regions on the galactic plane, colour excess per unit distance seems to show a linear decrease outwardly. If we adopt van de Hulst's model of grain formation, this decrease yields outward decrease of grain density. But both decreases cannot be connected directly. Sizes of grains give negative effect to the decrease of colour excess inside about R=10 kpc. The mean grain size becomes larger in the outer parts of the galactic plane owing to lower density which is favourable for grains to grow excessively.
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| Format: | Journal Contribution biblioteca |
| Language: | English |
| Published: |
1962
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| Online Access: | http://hdl.handle.net/1834/16924 |
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