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On the redistribution of ob star luminosity and the warming of nearby molecular clouds
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Leisawitz, D. |
| Copyright Year | 1987 |
| Description | Infrared Astronomy Satellite (IRAS) observations of the neighborhoods of six outer-Galaxy HII regions were combined with CO observations to show that most of the far infrared (FIR) luminosity from within approximately 25 to 75 pc of the ionizing stars is contributed by dust in molecular clouds, not by dust in the low-density ionized gas. Dust associated with the clouds is warmed by absorption of UV and visible light from the cluster of stars responsible for the ionization. Most of the OB cluster starlight is not absorbed locally. A fraction of the order of 10% of the OB cluster luminosity is absorbed by nearby molecular clouds and reradiated as FIR light. The luminosity per unit mass for the heated clouds is approximately 3 to 13 solar luminosity/solar mass, approximately one order of magnitude greater than the corresponding ratio for clouds found near clusters without O stars, and two orders of magnitude greater than the ratio for dark clouds heated primarily by the interstellar radiation field. If the observations of clouds near outer-Galaxy HII regions are used to characterize the molecular clouds heated by HII regions in the inner-Galaxy, then at most 30% of the Galaxy's molecular cloud mass is actively engaged in the formation of massive stars at the present time. |
| File Size | 235927 |
| Page Count | 4 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19870014841 |
| Archival Resource Key | ark:/13960/t0gv0gv55 |
| Language | English |
| Publisher Date | 1987-05-01 |
| Access Restriction | Open |
| Subject Keyword | Astronomy Galactic Structure Dust Stellar Mass Molecular Clouds H Ii Regions Infrared Astronomy Infrared Astronomy Satellite Line Spectra Carbon Monoxide Star Clusters Stellar Luminosity Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
