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Stirring a Giant: Feedback in the Or...

Feddersen, Jesse Robb.

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Stirring a Giant: Feedback in the Orion A Molecular Cloud.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Stirring a Giant: Feedback in the Orion A Molecular Cloud./
作者:	Feddersen, Jesse Robb.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2019,
面頁冊數:	207 p.
附註:	Source: Dissertations Abstracts International, Volume: 81-10, Section: B.
Contained By:	Dissertations Abstracts International81-10B.
標題:	Astronomy. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=22624571
ISBN:	9798607312527

Stirring a Giant: Feedback in the Orion A Molecular Cloud.
Feddersen, Jesse Robb.

Stirring a Giant: Feedback in the Orion A Molecular Cloud. - Ann Arbor : ProQuest Dissertations & Theses, 2019 - 207 p.

Source: Dissertations Abstracts International, Volume: 81-10, Section: B.

Thesis (Ph.D.)--Yale University, 2019.

This item must not be sold to any third party vendors.

Stars form via gravitational collapse of cold, dark clouds of molecular gas. But stars are neither cold nor dark. This thesis concerns the balance between the star-forming power of gravity and feedback: energy and momentum imparted by newly formed stars on their host clouds. Using the unprecedented combination of angular resolution and spatial coverage provided by the CARMA-NRO Orion Survey, I investigate the impacts of feedback on the Orion A molecular cloud. First, I present a survey of expanding spherical CO shells around low- to intermediate-mass young stars in Orion A. The shells inject enough energy and momentum to maintain turbulence in the cloud. The mass-loss rates needed to power the observed shells are two to three orders of magnitude higher than predicted for main-sequence stellar winds. Next, I compare gas statistics to the impact of feedback in different parts of Orion A to test if feedback changes the structure or kinematics of the cloud as predicted by molecular cloud simulations. I characterize the cloud using the covariance matrix, spectral correlation function, and spatial power spectrum. The CO spectral correlation function steepens with greater surface density of young stars, suggesting this statistic may be sensitive to feedback. The CO covariance matrix shows peaks at 1-3 km s−1 toward several regions that may be produced by feedback. Finally, I present a survey of protostellar outflows in Orion A. I identify 45 outflows, including 11 that are newly detected. I measure the mass and energetics of the outflows, including corrections for velocity-dependent opacity and low-velocity outflow emission. The total momentum and kinetic energy of the outflows is significant compared to that required to maintain tur-bulence. I also compare the orientation of outflows with dense filamentary structure traced by C18O. Outflows in Orion A show a moderately perpendicular alignment to their host filaments, suggesting the protostellar spin is correlated to processes at much larger cloud scales.

ISBN: 9798607312527Subjects--Topical Terms:

517668
Astronomy.
Subjects--Index Terms:

Astronomy

Stirring a Giant: Feedback in the Orion A Molecular Cloud.
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500 $a Source: Dissertations Abstracts International, Volume: 81-10, Section: B.
500 $a Advisor: Arce, Hector.
502 $a Thesis (Ph.D.)--Yale University, 2019.
506 $a This item must not be sold to any third party vendors.
520 $a Stars form via gravitational collapse of cold, dark clouds of molecular gas. But stars are neither cold nor dark. This thesis concerns the balance between the star-forming power of gravity and feedback: energy and momentum imparted by newly formed stars on their host clouds. Using the unprecedented combination of angular resolution and spatial coverage provided by the CARMA-NRO Orion Survey, I investigate the impacts of feedback on the Orion A molecular cloud. First, I present a survey of expanding spherical CO shells around low- to intermediate-mass young stars in Orion A. The shells inject enough energy and momentum to maintain turbulence in the cloud. The mass-loss rates needed to power the observed shells are two to three orders of magnitude higher than predicted for main-sequence stellar winds. Next, I compare gas statistics to the impact of feedback in different parts of Orion A to test if feedback changes the structure or kinematics of the cloud as predicted by molecular cloud simulations. I characterize the cloud using the covariance matrix, spectral correlation function, and spatial power spectrum. The CO spectral correlation function steepens with greater surface density of young stars, suggesting this statistic may be sensitive to feedback. The CO covariance matrix shows peaks at 1-3 km s−1 toward several regions that may be produced by feedback. Finally, I present a survey of protostellar outflows in Orion A. I identify 45 outflows, including 11 that are newly detected. I measure the mass and energetics of the outflows, including corrections for velocity-dependent opacity and low-velocity outflow emission. The total momentum and kinetic energy of the outflows is significant compared to that required to maintain tur-bulence. I also compare the orientation of outflows with dense filamentary structure traced by C18O. Outflows in Orion A show a moderately perpendicular alignment to their host filaments, suggesting the protostellar spin is correlated to processes at much larger cloud scales.
590 $a School code: 0265.
650 4 $a Astronomy. $3 517668
653 $a Astronomy
653 $a Feedback
653 $a Molecular cloud
653 $a Orion
653 $a Star formation
653 $a Turbulence
690 $a 0606
710 2 $a Yale University. $b Astronomy. $3 3550212
773 0 $t Dissertations Abstracts International $g 81-10B.
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791 $a Ph.D.
792 $a 2019
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=22624571