Program: GN-2017B-C-6

We propose to obtain GMOS Spectroscopy of the candidate White Dwarf (WD) companion to PSR J2317+1439. This pulsar has been estimated to have a mass of ~2.8 solar masses based on our CFHT imaging data. PSR J2317+1439 may be the most massive pulsar known to date. Current constraint of the pulsar mass relies on the photometry of the WD and the parallax measurement of the pulsar. Gemini spectroscopy will enable us to verify the nature of the WD companion and measure the WD and pulsar mass independently of the photometry and parallax. If PSR J2317+1439 is confirmed to be more massive than 2 solar masses, it may revolutionise our understanding of neutron star inner structure and have important implications for both fundamental physics and astrophysics. These observations will be our starting point for future orbital phase-resolved spectroscopy.