Caltech Library System

About | Browse | Search | Caltech Student Instructions

Type of Document	Dissertation
Author	Anderson, Christopher Marlowe
URN	etd-09232005-080803
Persistent URL	http://resolver.caltech.edu/CaltechETD:etd-09232005-080803
Title	The interstellar extinction of stars in H II regions
Degree	PhD
Option	Astronomy
Advisory Committee	Advisor Name Title Guido Münch Committee Chair
Keywords	none
Date of Defense	1968-01-19
Availability	unrestricted
Abstract 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.
Files	Filename       Size       Approximate Download Time (Hours:Minutes:Seconds)     28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access    Anderson_cm_1968.pdf 5.87 Mb 00:27:10 00:13:58 00:12:13 00:06:06 00:00:31