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What are pulsar companions made of? Using gravitational tides to probe their compositions

Liam Colombo-Murphy1,2,*, Lucas Brown2,3, Stefano Profumo2,3, M. Grant Roberts2,3, and Aya Westerling2

  • *Contact author: l.colombo-murphy@columbia.edu
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Phys. Rev. D 114, 103018 – Published 10 November, 2026

DOI: https://doi.org/10.1103/mh8d-1b6b

Abstract

Low eccentricity, short orbital period pulsar companions may provide a probe to study uniquely dense and stable exoplanet internal compositions due to the potentially high orbital evolution they experience caused by strong gravitational tides. We model the tidal characteristics such as apsidal motion constants, orbital precession, and tidal deformability for a variety of equations of state to be compared with values recovered via pulsar timing for a sample of two systems: PSR J1719-1438b and PSR J0636+5128b. With more time observing these companions through pulsar time of arrival measurements and the James Webb Space Telescope (JWST) enabling improved constraints on companion parameters, it may be possible to use this method in the future to improve limits on their chemical and structural compositions and provide more information on their unique history and formation.

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Phys. Rev. D 114, 103018– Published 10 November, 2026
  • Received 30 April 2026
  • Accepted 14 October 2026
Article part of CHORUS
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