Parkes observations for project P1021 semester 2019OCTS_06

We propose to conduct observations of PSR J1653-45, a 951-ms pulsar in a long, 1.5-yr orbit. Binary pulsars are valuable objects of scientific study, allowing for a wide range of applications, including tests of gravity, probes of the neutron star equation of state, and fossil records of stellar evolution. Long spin-period pulsars in binary systems are generally much rarer than faster-spinning `recycled’ pulsars, and represent an under-explored region of pulsar binary evolution.\r\n\r\nIn addition to its long orbital period, PSR J1653-45 also experiences extended eclipses, lasting up to half of the orbital period and whose nature is not well understood. These eclipses have also prevented the determination of an orbital of phase-connected timing solution, both vital steps in allowing for the continued study of this system. We propose a targeted, high-cadence observing campaign designed to monitor this pulsar as it transition into its eclipsing state. The campaign has the twin goals of both monitoring how the eclipse affects the pulsar’s emission properties, thereby revealed more about the nature of the eclipses themselves, and of extracting as much information regarding the pulsar’s orbit during its least-explored regions, thereby constrained and hopefully solving the pulsar’s orbit and ideally leading to the development of a timing solution. In both instances, we hope to gain a greater understanding of this pulsar’s properties and how it fits into this under-explored class of unrecycled pulsar binaries.

我们提议对PSR J1653-45开展观测研究，这是一颗轨道周期长达1.5年、自转周期为951毫秒的脉冲星。双星脉冲星是极具科学价值的研究对象，其应用范围广泛，包括引力测试、中子星状态方程探测以及恒星演化的化石记录。双星系统中的长自转周期脉冲星通常比自转更快的“再生”脉冲星稀少得多，代表了脉冲星双星演化中尚未充分探索的领域。

除长轨道周期外，PSR J1653-45还存在持续时间可达轨道周期一半的长时间掩食现象，其本质尚不清楚。这些掩食也阻碍了轨道相位连接计时解的确定——这两项均是持续研究该系统的关键步骤。我们提议开展针对性的高频率观测计划，以监测该脉冲星进入掩食状态的过程。该计划具有双重目标：一是监测掩食如何影响脉冲星的辐射特性，从而揭示掩食现象本身的本质；二是提取脉冲星在其探索最少区域的轨道信息，从而约束并有望解算脉冲星轨道，理想情况下得到计时解。通过这两方面的研究，我们希望能更深入地了解该脉冲星的特性及其在这一未充分探索的非再生脉冲星双星类别中的位置。