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The Interstellar Extinction of Stars in H II Regions


Anderson, Christopher Marlowe (1968) The Interstellar Extinction of Stars in H II Regions. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/DH4K-AB89.


NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. Spectrophotometric observations of several stars which appear to be associated with H II regions have been obtained in an attempt to locate other occurences of the reddening anomaly which is seen in the Trapezium stars [...] in the Orion Nebula. Several cases of the Orion-like anomaly have been found. The radiation pressure mechanism for the removal of the smallest grains from the nebula has been discussed and has been found to be inoperative because of the drag forces acting upon the grains. It has been shown that the temperature of the grains depends upon the grain size such that the smaller grains might experience more rapid evaporation. The processes of grain-grain fusion and condensation nucleus exhaustion have been investigated as possible causes of the anomalous grain size distribution. Finally, the anomaly has been discussed as if it were a peculiarity in the intrinsic colors of the stars. The large infrared excess observed in these stars could be due to the presence of late-type stellar companions or circumstellar shells.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Astronomy)
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Astronomy
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Münch, Guido
Group:Astronomy Department
Thesis Committee:
  • Unknown, Unknown
Defense Date:19 January 1968
Record Number:CaltechETD:etd-09232005-080803
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3723
Deposited By: Imported from ETD-db
Deposited On:23 Sep 2005
Last Modified:25 Mar 2024 21:12

Thesis Files

PDF (Anderson_cm_1968.pdf) - Final Version
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