Very long baseline astrometry of PSR J1012+5307 and its implications on alternative theories of gravity

Understand

PSR J1012+5307, a millisecond pulsar in orbit with a helium white dwarf (WD), has been timed with high precision for about 25 years.

• One of the main objectives of this long-term timing is to use the large asymmetry in gravitational binding energy between the neutron star and the WD to test gravitational theories.
• Such tests, however, will be eventually limited by the accuracy of the distance to the pulsar.
• Here, we present VLBI (very long baseline interferometry) astrometry results spanning approximately 2.5 years for PSR J1012+5307, obtained with the Very Long Baseline Array as part of the MSPSRPI project.