skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Submillimeter observations of evolved stars

Abstract

Broad-band submillimeter observations of the thermal emission from evolved stars have been obtained with the United Kingdom Infrared Telescope on Mauna Kea, Hawaii. These observations, at an effective wavelength of 400 ..mu..m, provide the most direct method for estimating the mass loss rate in dust from these stars and also help to define the long-wavelength thermal spectrum of the dust envelopes. The mass loss rates in dust that we derive range from 10/sup -9/ to 10/sup -6/ M/sub sun/ yr/sup -1/ and are compared with mass loss rates derived from molecular line observations to estimate gas-to-dust ratios in outflowing envelopes. These values are found to be generally compatible with the interstellar gas-to-dust ratio of approx.100 if submillimeter emissivities appropriate to amorphous grain structures are assumed. Our analysis of the spectrum of IRC+10216 confirms previous suggestions that the grain emissivity varies as lambda/sup -1.2/ rather than as lambda/sup -2/ for 10<1000 ..mu..m. The overall properties of the model that we use in the analysis of IRC+10216 are found to be applicable to the similar carbon-rich object CRL 3068. Similar analysis of the spectra of oxygen-rich objects indicates that our submillimeter fluxes for IRC+10011 and NML Cyg are greater than those predictedmore » by previous modeling. This, we argue, is the result of a slower decline in grain emissivity with wavelength than is seen in published silicate grain models. We are not able to distinguish a systematic difference in the dust masses of carbon-rich and oxygen-rich envelopes. We find the largest mass loss rates in dust in the bipolar objects OH 231.8+4.2, CRL 2688, and CRL 618 and in NGC 7027 and VY CMa.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
University of Maryland and Catonsville Community College
OSTI Identifier:
5308697
Resource Type:
Journal Article
Journal Name:
Astrophys. J.; (United States)
Additional Journal Information:
Journal Volume: 294:1
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; INTERSTELLAR GRAINS; EMISSIVITY; STAR EVOLUTION; MASS TRANSFER; STARS; CARBON; COSMIC DUST; COSMIC GASES; INFRARED RADIATION; OXYGEN; SILICATES; DUSTS; ELECTROMAGNETIC RADIATION; ELEMENTS; FLUIDS; GASES; NONMETALS; OPTICAL PROPERTIES; OXYGEN COMPOUNDS; PARTICLES; PHYSICAL PROPERTIES; RADIATIONS; SILICON COMPOUNDS; SURFACE PROPERTIES; 640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar, Radio & X-Ray Sources

Citation Formats

Sopka, R J, Hildebrand, R, Jaffe, D T, Gatley, I, Roellig, T, Werner, M, Jura, M, and Zuckerman, B. Submillimeter observations of evolved stars. United States: N. p., 1985. Web. doi:10.1086/163293.
Sopka, R J, Hildebrand, R, Jaffe, D T, Gatley, I, Roellig, T, Werner, M, Jura, M, & Zuckerman, B. Submillimeter observations of evolved stars. United States. https://doi.org/10.1086/163293
Sopka, R J, Hildebrand, R, Jaffe, D T, Gatley, I, Roellig, T, Werner, M, Jura, M, and Zuckerman, B. 1985. "Submillimeter observations of evolved stars". United States. https://doi.org/10.1086/163293.
@article{osti_5308697,
title = {Submillimeter observations of evolved stars},
author = {Sopka, R J and Hildebrand, R and Jaffe, D T and Gatley, I and Roellig, T and Werner, M and Jura, M and Zuckerman, B},
abstractNote = {Broad-band submillimeter observations of the thermal emission from evolved stars have been obtained with the United Kingdom Infrared Telescope on Mauna Kea, Hawaii. These observations, at an effective wavelength of 400 ..mu..m, provide the most direct method for estimating the mass loss rate in dust from these stars and also help to define the long-wavelength thermal spectrum of the dust envelopes. The mass loss rates in dust that we derive range from 10/sup -9/ to 10/sup -6/ M/sub sun/ yr/sup -1/ and are compared with mass loss rates derived from molecular line observations to estimate gas-to-dust ratios in outflowing envelopes. These values are found to be generally compatible with the interstellar gas-to-dust ratio of approx.100 if submillimeter emissivities appropriate to amorphous grain structures are assumed. Our analysis of the spectrum of IRC+10216 confirms previous suggestions that the grain emissivity varies as lambda/sup -1.2/ rather than as lambda/sup -2/ for 10<1000 ..mu..m. The overall properties of the model that we use in the analysis of IRC+10216 are found to be applicable to the similar carbon-rich object CRL 3068. Similar analysis of the spectra of oxygen-rich objects indicates that our submillimeter fluxes for IRC+10011 and NML Cyg are greater than those predicted by previous modeling. This, we argue, is the result of a slower decline in grain emissivity with wavelength than is seen in published silicate grain models. We are not able to distinguish a systematic difference in the dust masses of carbon-rich and oxygen-rich envelopes. We find the largest mass loss rates in dust in the bipolar objects OH 231.8+4.2, CRL 2688, and CRL 618 and in NGC 7027 and VY CMa.},
doi = {10.1086/163293},
url = {https://www.osti.gov/biblio/5308697}, journal = {Astrophys. J.; (United States)},
number = ,
volume = 294:1,
place = {United States},
year = {Mon Jul 01 00:00:00 EDT 1985},
month = {Mon Jul 01 00:00:00 EDT 1985}
}