A parallax distance and mass estimate for the transitional millisecond pulsar system J1023+0038. (arXiv:1207.5670v1 [astro-ph.SR])

A parallax distance and mass estimate for the transitional millisecond pulsar system J1023+0038. (arXiv:1207.5670v1 [astro-ph.SR]):
The recently discovered transitional millisecond pulsar system J1023+0038
exposes a crucial evolutionary phase of recycled neutron stars for
multiwavelength study. The system, comprising the neutron star itself, its
stellar companion, and the surrounding medium, is visible across the
electromagnetic spectrum from the radio to X-ray/gamma-ray regimes and offers
insight into the recycling phase of millisecond pulsar evolution. Here, we
report on multiple-epoch astrometric observations with the Very Long Baseline
Array (VLBA) which give a system parallax of 0.731 +/- 0.022 milliarcseconds
(mas) and a proper motion of 17.98 +/- 0.05 mas/yr. By combining our results
with previous optical observations, we are able to use the parallax distance of
1368+42-39 pc to estimate the mass of the pulsar as 1.71 +/- 0.16 solar masses,
and we are also able to measure the 3D space velocity of the system as 126 +/-
5 km/s. Despite the precise nature of the VLBA measurements, the remaining ~3%
distance uncertainty dominates the 0.16 solar mass error on our mass estimate.