Parkes observations for project P1313 semester 2024APRS_02

Pulsars orbiting high-mass stellar companions provide a novel means of directly probing the space weather of these comparatively uncommon stars. PSR J1638-4725 is one such binary system for which little has been published to date. It displays an extraordinary amount of variability in its detected radio emission, which could be used to answer fundamental questions about the nature of the companion star and the intra-binary environment. This includes: What is the exact nature of the companion star? What does the circumbinary environment in this system look like? And can we use this system as a Galactic fast radio burst analogue? Obtaining answers to these questions with existing data sets is challenging, as the variable pulsar properties make it extremely difficulty to obtain a coherent timing solution across several orbits of the system. In order to address this problem, we request a set of high-cadence observations of PSR J1638-4725 with the Ultra-Wideband Low (UWL) receiver system. This will allow us to obtain an initial timing solution, from which we can re-derive the orbital properties of the system and begin answering the above questions.