A Search for Dwarf Novae in Globular Cluster 47 Tucanae

Abstract



Until recently, no dwarf novae have been known to exist in globular clusters. Because of the density of stars that form these clusters, one may expect many such binary systems. Dwarf novae are easy to detect because of their relatively short recurrence times, ranging from 20 to 300 days, as compared with the 10,000 (or more) year recurrence times of classical novae. Dwarf novae also have amplitude outbursts of 2-6 in magnitude, making them easily visible. 47 Tucanae has been chosen for observation, as it appears in the right location at the right time of year, and has characteristics of an average globular cluster with moderately poor metallicity. This helps minimize any difference in metallicity of the dwarf novae, while still allowing for study of these differences.

Data obtained over a period of five months from the 1m YALO telescope at Cerro Tololo Inter-American Observatory has been reduced and subtracted. To date, several variable stars have been found through visual means, but no dwarf novae. Further analysis of this data, as well as new data, may provide a more optimistic outcome. If found, study of these dwarf novae will provide a look at the stellar dynamics of globular clusters. For now, we can conclude that dwarf novae are indeed rare in globular clusters.





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