"The anomalous behavior of aluminum oxide bands in mira variables."

Series: The Astrophysical Journal, Vol. 158, October 1969. 8vo. 261-268 pp. 8 figs., 5 plates. Self-wraps. Fine. ABSTRACT: In spectra of normal M giants, absorption bands of A1O occur with an intensity that is well correlated with the spectral type as defined by the TiO bands. In Mira variables, however, the AlO band can vary greatly from cycle to cycle and can be abnormally strong or weak for the spectral type. This behavior is not shared by other molecules, such as ScO and VO, which vary predictably with spectral type. / In some Mira variables the AlO bands haye been observed to go over into emission. This record in Mira in 1924 and 1964, R Scr in 1960. R Psc in 1966, R Crv and R Casin 1967, and RT Lib in 1968. / From a survey of all spectrograms of Mira itself available at Mount Wilson and Palomar Observatories in 1967, we find that the AIO bands tend to be strong in absorption during "strong line" cycles and tend to be weak or reversed in "weak line" cycles . . . In the absorption spectra of long-period variable stars, there are seemingly arbitrary variations superposed on predictable temperature and pressure effects. One of the most noticeable of these spectral variations is the occurrence of "weak line" cycles, described in detail by Merrill, Deutsch, and Keenan (1962, hereinafter referred to as MDK). Another is the behavior of the blue bands of the AlO molecule. The characteristic with which we are concerned in this paper is the great variation of the AlO bands from cycle to cycle in certain Mira variables. / . . . The Mount Wilson-Palomar plate files contain a great many spectrograms of long period variable stars, due to the interest shown in these stars over the last 50 years by members of the staff, especially A. H. Joy and P. W. Merrill. To this wealth of material has been added a series of coude plates taken over several years by P. C. Keenan and A. J. Deutsch. During the last two years the authors have undertaken a concentrated observational program consisting of a survey at 80-85 A mm by one of us (R, F. G.), using the 60 inch telescope on Mount Wilson and the Perkins 72-inch telescope in Flagstaff, and a 20 . . .

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Publisher: The Astrophysical Journal, 1969.

Year: 1969

Type: Used

Binding: Softcover

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