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A non-PRE double-peaked burst from 4U 1636-536: evidence for burning front propagation

Sudip Bhattacharyya·Tod E. Strohmayer
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Abstract

We analyse Rossi X-ray Timing Explorer (RXTE) Proportional Counter Array (PCA) data of a double-peaked burst from the low mass X-ray binary (LMXB) 4U 1636--536 that shows no evidence for photospheric radius expansion (PRE). We find that the X-ray emitting area on the star increases with time as the burst progresses, even though the photosphere does not expand. We argue that this is a strong indication of thermonuclear flame spreading on the stellar surface during such bursts. We propose a model for such double-peaked bursts, based on thermonuclear flame spreading, that can qualitatively explain their essential features, as well as the rarity of these bursts.

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Sudip Bhattacharyya, Tod E. Strohmayer. 2005-12-03. A non-PRE double-peaked burst from 4U 1636-536: evidence for burning front propagation. https://doi.org/10.1086/500199

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