The GMRT High-Resolution Southern Sky Survey for pulsars and transients -- VII: Timing of Spider MSP J1242-4712, A Bridge Between Redback and Black Widow Pulsars

Ankita Ghosh; Bhaswati Bhattacharyya; Andrew Lyne; David L. Kaplan; Jayanta Roy; Paul S. Ray; Ben Stappers; Sangita Kumari; Shubham Singh; Rahul Sharan

arXiv · 2403.02646

The GMRT High-Resolution Southern Sky Survey for pulsars and transients -- VII: Timing of Spider MSP J1242-4712, A Bridge Between Redback and Black Widow Pulsars

Ankita Ghosh·Bhaswati Bhattacharyya·Andrew Lyne·David L. Kaplan·Jayanta Roy·Paul S. Ray·Ben Stappers·Sangita Kumari·Shubham Singh·Rahul Sharan

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Abstract

We present the timing solution for the 5.31-ms spider millisecond pulsar (MSP) J1242-4712, discovered with the GMRT. PSR J1242-4712 orbits a companion of minimum mass 0.08 M$_{\odot}$ with an orbital period of 7.7 hrs and occupies a relatively unexplored region in the orbital period versus companion mass space. We did not detect gamma-ray pulsations for this MSP, and also could not identify the optical counterpart for PSR J1242-4712 in available optical/near-infrared data. The profile of J1242-4712 evolves with frequency showing a clear single component at lower frequencies and a three-component profile at 650 MHz. PSR J1242-4712 eclipses for a very short duration near superior conjunction (orbital phase ~ 0.23-0.25) below 360 MHz. Moreover, significant DM delays and errors in pulse times of arrivals are observed near inferior conjunction (orbital phase ~ 0.7), along with an observed eclipse in one epoch at 650 MHz. Observed eclipses and significant orbital period variability suggest that PSR J1242-4712 is possibly not a He-WD binary, but has a semi or non-degenerate companion, indicating that this is a ``spider" MSP lying in a region between typical black widows and redbacks. This system may represent a distinct category of spider MSPs, displaying characteristics that bridge the gap between known black widow and redback MSPs.

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Ankita Ghosh, Bhaswati Bhattacharyya, Andrew Lyne, David L. Kaplan, Jayanta Roy, Paul S. Ray, Ben Stappers, Sangita Kumari, Shubham Singh, Rahul Sharan. 2024-03-05. The GMRT High-Resolution Southern Sky Survey for pulsars and transients -- VII: Timing of Spider MSP J1242-4712, A Bridge Between Redback and Black Widow Pulsars. https://arxiv.org/abs/2403.02646

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