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arXiv · 2610.22587

Searching for Dwarf Novae in 47 Tucanae

Iman Behbehani·Michael Shara·David Zurek
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Abstract

The globular cluster 47 Tucanae has 43 strong cataclysmic variable candidates, four of which are confirmed dwarf novae. Tidal capture theory predicts the existence of dozens of dwarf novae, suggesting more are undiscovered. Using 435 nm and 475 nm long exposure images from Hubble's ACS camera, we searched five epochs of archival Hubble images and did not find any variability at the scale of a dwarf nova eruption. We found 1 previously undiscovered variable object on the main sequence that could not be classified as a CV; the object experienced a change of approximately 0.3 Mag in 425 nm, and 0.2 mag in 635 nm over the course of 12 days. The lack of new CV detections in 47 Tucanae could be a result of the short timescale of the DN eruption, and a low observing probability. However, this null result may also support research suggesting most CVs in globular clusters are not dynamically formed, and tidal capture theory overestimates the detectable CV population.

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Iman Behbehani, Michael Shara, David Zurek. 2026-10-15. Searching for Dwarf Novae in 47 Tucanae. https://arxiv.org/abs/2610.22587

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