Radio timing constraints on the orbital orientation and component masses of PSR J1455−3330

¹ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany
² Jodrell Bank Centre for Astrophysics, University of Manchester, M13 9PL, Cheshire, UK
³ LPC2E, OSUC, Univ Orleans, CNRS, CNES, Observatoire de Paris, F-45071 Orleans, France
⁴ ORN, Observatoire de Paris, Université PSL, Univ Orléans, CNRS, 18330 Nançay, France
⁵ Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
⁶ The Australian Research Council Centre of Excellence for Gravitational Wave Discovery (OzGrav), Hawthorn, Australia
⁷ INAF – Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius (CA), Italy
⁸ High Energy Physics, Cosmology & Astrophysics Theory (HEPCAT) Group, Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch 7701, South Africa
⁹ FORTH Institute of Astrophysics, N. Plastira 100, 70013 Heraklion, Greece
¹⁰ State Key Laboratory of Radio Astronomy and Technology, Shanghai Astronomical Observatory, CAS, 80 Nandan Road, Shanghai 200030, P. R. China
¹¹ Dipartimento di Fisica “G. Occhialini”, Università degli Studi di Milano-Bicocca, Piazza della Scienza 3, I-20126 Milano, Italy
¹² INFN, Sezione di Milano-Bicocca, Piazza della Scienza 3, 20126 Milano, Italy

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Received: 6 August 2025
Accepted: 12 January 2026

Abstract

PSR J1455−3330 is a ∼7.98 ms pulsar in a ∼76.17 day nearly circular orbit with a white dwarf companion. In this work, we combine the available Lovell, Nançay decimetric Radio Telescope, Green Bank, and MeerKAT pulsar timing data spanning approximately 30 years to measure the kinematic and relativistic effects of PSR J1455−3330 to constrain its 3D orbital geometry and component masses. We detect a relativistic Shapiro delay signal. We measure a significant orthometric amplitude of h₃ = 0.307^+0.022_−0.026 μs and an orthometric ratio of ς = 0.551^+0.057_−0.054. We measured the change in projected semi-major axis, x˙ = −202.1^+2.5_−2.7 × 10⁻¹⁶ s s⁻¹, with high significance, parallax, ϖ = 1.11(6) mas, parallax derived distance 0.90(5) kpc, and a precise total proper motion magnitude of 12.432(2) mas yr⁻¹. A self-consistent analysis of all kinematic and relativistic effects, assuming general relativity, yielded two solutions: (1) a pulsar mass of M_p = 1.39^+0.38_−0.18 M_⊙, a companion mass of M_c = 0.293^+0.056_−0.026 M_⊙, an orbital inclination of i = 63(2)°, and a longitude of the ascending node of Ω = 212(12)° or (2) a pulsar mass of M_p = 1.53^+1.10_−0.22 M_⊙, a companion mass of M_c = 0.309^+0.163_−0.026 M_⊙, an orbital inclination of i = 123(4)°, and a longitude of the ascending node of Ω = 334(12)°. All uncertainties represent the 68.27% credibility region. These results strongly favour a helium-dominated white dwarf companion.