An observational study of the dynamics of molecular cloud cores.
| dc.contributor.author | Walker, Christopher Kidd. | |
| dc.creator | Walker, Christopher Kidd. | en_US |
| dc.date.accessioned | 2011-10-31T17:12:40Z | |
| dc.date.available | 2011-10-31T17:12:40Z | |
| dc.date.issued | 1988 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10150/184585 | |
| dc.description.abstract | How are stars formed? This is one of the most fundamental questions in astronomy. It is therefore ironic that to date, no object has been unambiguously identified as a true protostar; an object which derives the bulk of its luminosity from accretion. While this may be ironic, it is not surprising. Stars are believed to form as a result of the gravitational collapse of a portion of a molecular cloud. Theory predicts that the cloud core in which the star is formed will be cold, dense and possess hundreds of magnitudes of extinction, rendering it opaque at visible and near-infrared wavelengths. Continuum observations at far-infrared, submillimeter, and millimeter wavelengths can be used to identify candidate protostars, but spectroscopic observations are needed to detect infall. The difficulties arise when there are systematic velocity fields present in the cloud core which are not the result of infall, such as would be produced by either a molecular outflow or rotation. In this dissertation we use both observations and theoretical models to sort through these problems and develop a strategy which could be used to identify and study protostars. | |
| dc.language.iso | en | en_US |
| dc.publisher | The University of Arizona. | en_US |
| dc.rights | Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. | en_US |
| dc.subject | Stars -- Formation. | en_US |
| dc.subject | Molecular clouds. | en_US |
| dc.subject | Protostars. | en_US |
| dc.title | An observational study of the dynamics of molecular cloud cores. | en_US |
| dc.type | text | en_US |
| dc.type | Dissertation-Reproduction (electronic) | en_US |
| dc.identifier.oclc | 701865701 | en_US |
| thesis.degree.grantor | University of Arizona | en_US |
| thesis.degree.level | doctoral | en_US |
| dc.identifier.proquest | 8906395 | en_US |
| thesis.degree.discipline | Astronomy | en_US |
| thesis.degree.discipline | Graduate College | en_US |
| thesis.degree.name | Ph.D. | en_US |
| dc.description.note | This item was digitized from a paper original and/or a microfilm copy. If you need higher-resolution images for any content in this item, please contact us at repository@u.library.arizona.edu. | |
| dc.description.admin-note | Original file replaced with corrected file August 2023. | |
| refterms.dateFOA | 2018-08-19T10:47:57Z | |
| html.description.abstract | How are stars formed? This is one of the most fundamental questions in astronomy. It is therefore ironic that to date, no object has been unambiguously identified as a true protostar; an object which derives the bulk of its luminosity from accretion. While this may be ironic, it is not surprising. Stars are believed to form as a result of the gravitational collapse of a portion of a molecular cloud. Theory predicts that the cloud core in which the star is formed will be cold, dense and possess hundreds of magnitudes of extinction, rendering it opaque at visible and near-infrared wavelengths. Continuum observations at far-infrared, submillimeter, and millimeter wavelengths can be used to identify candidate protostars, but spectroscopic observations are needed to detect infall. The difficulties arise when there are systematic velocity fields present in the cloud core which are not the result of infall, such as would be produced by either a molecular outflow or rotation. In this dissertation we use both observations and theoretical models to sort through these problems and develop a strategy which could be used to identify and study protostars. |
