Parkes observations for project P1386 semester 2025OCTS_13

J0045-7319 is a B star/pulsar binary in the Small Magellanic Cloud (SMC) with an orbital period of 51 days. The system is highly eccentric, with a closest approach of only 6 B-star radii, and it offers an unusual probe into massive stars in the SMC. Although similar systems exhibit strong dispersion measure (DM) variation during periastron arising from the stellar wind, observations in 1996 on the Parkes 70 cm receiver found no evidence of a wind from the B star. We propose a new set of observations on the Ultra-Wide Low-frequency receiver (UWL) designed to measure the wind. A null result will decrease the known upper limit on the B-star wind's contribution to DM by a factor of 9.

J0045-7319 是小麦哲伦星系（Small Magellanic Cloud, SMC）中的一颗B型星/脉冲星双星系统，轨道周期为51天。该系统具有极高的偏心率，近星距仅为6倍B型星半径，为研究小麦哲伦星系中的大质量恒星提供了独特的观测探针。尽管同类天体系统在近星点阶段会因恒星风产生显著的色散量（dispersion measure, DM）变化，但1996年使用帕克斯（Parkes）70厘米接收机开展的观测并未发现该B型星存在恒星风的迹象。我们提议使用超宽频低频接收机（Ultra-Wide Low-frequency receiver, UWL）开展新一轮观测以探测该恒星风。若本次观测得到零结果，则可将B型星风对色散量贡献的已知上限降至原上限的1/9。