Spin Evolution and Characteristics of BeXRB Pulsar SXP 46.6

The Small Magellanic Cloud (SMC) is an ideal laboratory for studying Be/X-ray binaries (BeXRBs) due to its relative proximity and the large population of identified BeXRB pulsars. One such SMC pulsar is SXP 46.6, originally discovered by RXTE in 1997. We present the timing and spectral analysis of a 2016 NuSTAR observation of this source. The pulse profile, analyzed in soft (3–8 keV), hard (8–50 keV), and broad (3–50 keV) X-ray bands, shows a double peak structure, consistent with emission from two hot spots on the neutron star’s surface. Additionally, we measure a continuous spin period change, indicating ongoing spin-up driven by accretion torque. This suggests efficient angular momentum transfer from the accretion disk to the neutron star, likely regulated by magnetospheric interactions. These results contribute to a deeper understanding of the system’s accretion processes and provide valuable insights into the pulse emission geometry and underlying physical mechanisms, (Kaushik et al. 2024 in preparation).