Characteristics Of Ir Variable Stars As Observed From Orbit

Stephen P. Maran; Thomas F. Heinsheimer; Thomas L. Stocker; Robert D. Chapman; Robert W. Hobbs; Andrew G. Michalitsanos

doi:10.1117/12.955154

15 November 1976 Characteristics Of Ir Variable Stars As Observed From Orbit

Stephen P. Maran, Thomas F. Heinsheimer, Thomas L. Stocker, Robert D. Chapman, Robert W. Hobbs, Andrew G. Michalitsanos

Proceedings Volume 0095, Modern Utilization of Infrared Technology II; (1976) https://doi.org/10.1117/12.955154
Event: 20th Annual Technical Symposium, 1976, San Diego, United States

Abstract

We have studied a selection of infrared variable stars at wavelength 2.7 μm during 1971-1975 with data from U.S. Air Force satellites. Stars observed in this program are classified as long-period variable stars, semiregular variables, and irregular variables and are among the strongest stellar sources at this wavelength. In addition, a few new, as yet unclassified variable stars were identified during the course of the investigation. Time scales of reproducible variations range from a few weeks to a few years, and amplitudes of variation are as large as a factor of three for stars with periods of order one year. The minimum infrared flux density of a long-period star repeats accurately from one cycle to the next, whereas the maximum flux density was found to be unstable. This behavior may be related to the propagation of shocks in the stellar atmosphere near the time of maximum light or to coupling between large-scale convection and pulsation. It suggests that phenomena in these stars be timed with respect to minimum phase, rather than maximum phase as done previously. Maximum infrared flux density occurs after maximum visible light, whereas the visible and infrared minima are essentially simultaneous. The correlation of 2.7 μm and radio emission line data from one, well-studied long-period variable is consistent with the hypothesis that the H2O and OH circumstellar masers are saturated, if pumped by the stellar infrared flux near 2.7 μm, as suggested by Litvak. However, an alternate model, namely that the radio maser clouds are pumped by long-wave infrared radiation, cannot be excluded.

Citation Download Citation

Stephen P. Maran, Thomas F. Heinsheimer, Thomas L. Stocker, Robert D. Chapman, Robert W. Hobbs, and Andrew G. Michalitsanos "Characteristics Of Ir Variable Stars As Observed From Orbit", Proc. SPIE 0095, Modern Utilization of Infrared Technology II, (15 November 1976); https://doi.org/10.1117/12.955154

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available