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

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 $ h_3 = 0.307^{+0.022}_{-0.026} $ μs and an orthometric ratio of $ \varsigma = 0.551^{+0.057}_{-0.054} $. We measured the change in projected semi-major axis, $ \dot{x} = -202.1^{+2.5}_{-2.7} \times10^{-16} \, \mathrm{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_{\mathrm{p}} = 1.39^{+0.38}_{-0.18}\, \mathrm{M}_{\odot} $, a companion mass of $ M_{\mathrm{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_{\mathrm{p}} = 1.53^{+1.10}_{-0.22} \, \mathrm{M}_{\odot} $, a companion mass of $ M_{\mathrm{c}} = 0.309^{+0.163}_{-0.026}\, \mathrm{M}_{\odot} $, 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.