A New Mid-Infrared Camera for Ground-Based Astronomy and an Infrared Study of Planetary Nebulae


Joseph Lee Hora

Copyright 1991

Copyright Notice

This version of the above titled dissertation is available on-line below. You are allowed to obtain one electronic copy and one "hard" or printed copy of the dissertation. This work is not in the public domain. All rights reserved. No part of the contents of this dissertation may be reproduced or transmitted in any form or by any means without the written permission of the copyright holder (Joseph Hora).

Original copyright notice

This dissertation has been submitted in partial fulfillment of requirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers under the rules of the Library.

Brief quotations from this dissertation are allowable without special permission, provided that accurate acknowledgement of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the copyright holder.


This dissertation is composed of two parts. The first part is a description of the Mid-Infrared Array Camera (MIRAC), a new camera for ground-based astronomy. The second part of this dissertation is an infrared study of planetary nebulae utilizing observations with the new camera. MIRAC is a collaborative effort among the University of Arizona, Smithsonian Astrophysical Observatory, and Naval Research Laboratory. It currently utilizes a Hughes 20x64 Si:As IBC detector array, which is sensitive to infrared (IR) radiation from 2 to 26 microns. The camera is equipped with 10% bandwidth filters at 2.2, 3.8, 4.6, 8.8, 9.8, 11.7, and 12.5 microns, and a wide band 8.0 to 12.8 micron "N" filter. There is also a 20% filter at 20.5 microns, and a 8-14 micron CVF with a resolution of 1.8%. The MIRAC electronics provides timing signals and coadds successive frames at a maximum rate of 10 KHz for the full array, and higher rates for a partial array readout. The data are transferred via a serial interface to a PC for storage and further processing. The camera recently achieved a NEFD of .010 Jy/arcsec2 at 8.8, 11.7, and 12.5 microns for a 900 second on-source integration on the Steward Observatory 1.5 m telescope.

Planetary Nebulae (PN) are formed when a star is in the post-Asymptotic Giant Branch stage of evolution. The ejection of circumstellar material is an important enrichment mechanism for the interstellar medium. In many PN, there is an excess of emission in the IR, indicating the presence of dust. There are several different components seen in the IR emission, including a family of unidentified IR (UIR) emission features at 3.3, 6.2, 7.7, and 11.3 microns. Images in the near- and mid-IR are presented here for the following PN: IC 418, BD+30°3639, J 900, NGC 2392, NGC 6543, AFGL 2688, and M 2-9. In IC 418 and BD+30°3639, the SiC and UIR emission is seen to be spatially distinct from the IR continuum. In NGC 2392 and NGC 6543, evidence for excess emission is seen in the distribution of the near-IR flux. In the bipolar nebulae AFGL 2688 and M 2-9, structures in the IR emission are seen that could be related to the equatorial density enhancements that have caused the bipolar morphology.

Downloading the files

The dissertation is available as a single PDF format file, and has also been divided up into seven parts to make downloading easier. If you have difficulty getting these, contact me (see below). Also, a copy of the dissertation can be obtained from University Microfilms, Inc. (UMI) -- see the contact information below. The UMI document number of this work is 9210322. There may be some discrepancies between the original published dissertation and this on-line version. The figures are on the same page as in the original, but some of the text may be slightly different due to the conversion in WordPerfect 5.0 from a HP printer to Postscript. If referring to page numbers when quoting from the work, please refer to the page numbers in the original manuscript.

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Full Dissertation - PDF format

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Last modified 1999 August 12