OH/IR masers. IV. Evolution, pulsation, and nature of the sources
The evolution, pulsation, and nature of the type II OH/IR stars is analyzed using the extensive data base and trends described in the third paper in this series. Using evolutionary tracks and pulsation theory, the lowest luminosity (M/sub bol/>-5) masers on the asymptotic giant branch (AGB) are shown to be cool, fundamental mode pulsators which are possibly metal rich. Comparison of the positions in the period-luminosity plane of the masers width the long-period variables in the Magellanic Clouds and in the Galactic bulge suggests that in fact all of the redder (>5) and more efficient (>1) masers on the AGB are fundamental mode pulsator. The periods of several of the bluer (<3) and less efficient (<0) AGB masers are consistent with first overtone pulsation; these objects are similar to the classical IRC Miras except bolometrically brighter. As well as the AGB maser sources, there is a class of sources which are core helium burning supergiants, but whether they pulsate in the fundamental or first overtone models or not at all is not clear at present.
- Research Organization:
- Mount Stromlo and Siding Spring Observatories, Research School of Physical Sciences, The Australian National University
- OSTI ID:
- 7010625
- Journal Information:
- Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 273:2; ISSN ASJOA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AMPLIFIERS
DIAGRAMS
ELECTROMAGNETIC RADIATION
ELECTRONIC EQUIPMENT
EQUIPMENT
GIANT STARS
HERTZSPRUNG-RUSSELL DIAGRAM
INFRARED RADIATION
LUMINOSITY
MASERS
MASS
MICROWAVE AMPLIFIERS
MICROWAVE EQUIPMENT
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PULSATIONS
RADIATIONS
STAR EVOLUTION
STARS
STELLAR WINDS
SUPERGIANT STARS
VARIABLE STARS