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arXiv · 2306.14949

Optical Identification of the Shortest-Period Spider Pulsar System M71E

Zhuokai Liu·Subo Dong
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Abstract

M71E is a spider pulsar (i.e., a millisecond pulsar with a tight binary companion) with the shortest known orbital period of P=53.3 min discovered by Pan et al. (2023). Their favored evolutionary model suggests that it bridges between two types of spider pulsars, namely, it descended from a "redback" and will become a "black widow". Using Hubble Space Telescope (HST) archival imaging data, we report the first optical identification of its companion COM-M71E. The HST and pulsar timing coordinates are in excellent agreement (within ~10 mas). If M71E is associated with the globular cluster M71, our measured brightness of COM-M71E (m_F606W ~ 25.3) is broadly consistent with the expectation from Pan et al. (2023)'s preferred binary evolutionary model of a stripped dwarf companion, while it is also compatible with an ultra-low-mass degenerate companion. Future multi-wavelength photometric and spectroscopic observations can characterize the companion and test the evolutionary scenarios.

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Zhuokai Liu, Subo Dong. 2023-06-26. Optical Identification of the Shortest-Period Spider Pulsar System M71E. https://arxiv.org/abs/2306.14949

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