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Some Background on R-Aquarii as an Eclipsing System

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Edwin B. Weston

80 Oak Street, Lexington, MA 02173

Abstract

Recently Willson, Garnavich, and Mattei (1981) suggested that the sybmiotic Mira variable R Aquarii may be an eclipsing system with a period of 44 years. Over 40 years ago, Dr. Paul W. Merrill at Mount Wilson Observatory and over 30 years ago, Dr. Dean B. McLaughlin at the University of Michigan also considered the possibility that it might be eclipsing, but neither considered the observational data at that time sufficient to warrant publication. Merrill appears to have kept an open mind as to whether R aquarii was a single or a binary star, and he continued to study it for the remainder of his life. McLaughlin favored a binary system, but also kept an open mind. Both recognized the physical relationship of R aquarii with an inner nebulosity and with the extended lower-density optical nebulosity. During my years as a graduat estudent at Michigan and Research Assistant to Dr. McLaughlin, we discussed R Aquarii many times in terms of the possible similarities and contrasts with other systems such as certain old novae; VV Cephei, ε Aurigae, and other long-period eclipsing binaries; the ο Ceti sytem; symbiotic stars; and certai nother peculiar objects.

Today we have, thanks to the dedicated work of the AAVSO, a much larger data base, but additional observations of R Aquarii will continue to be needed for many years tocome.