Detection of spin-modulated circular polarization and radial velocity variations in the long-period Intermediate Polar 1RXS J080114.6–462324

ABSTRACT We present a comprehensive photometric, spectroscopic, and polarimetric study of the intermediate polar (IP) 1RXS J080114. 6–462324, using observations from the South African Astronomical Observatory 1. 0m and 1. 9m telescopes and the Southern African Large Telescope, complemented by archival Transiting Exoplanet Survey Satellite (TESS) photometry. Photometric and photopolarimetric data reveal a coherent modulation at the white dwarf (WD) spin period. TESS confirms periodicities of 1307. 517 s (spin) and 11. 803 h (orbital). Photopolarimetric and circular spectropolarimetric measurements show circular polarization reaching +5 per cent, modulated with the WD spin period, consistent with cyclotron emission from an accreting magnetic pole. Timeresolved optical spectra display prominent Balmer (H, H, and H) and He ii 4686 emission features and additional He i emissions, all exhibiting minimal radial-velocity variations. We detect redshifted absorption dips adjacent to the He ii and H lines, modulated at the WD spin period; periodogram analysis of the emission lines also yields spin modulation. These observations indicate that the system is a discfed, lowinclination IP. The combination of circular polarization and spinmodulated absorption by infalling accretion curtain material supports this classification. Its comparatively long orbital period among IPs and the detection of polarized emission render 1RXS J080114. 6–462324 an appealing candidate for evolutionary studies, potentially offering insight into how magnetic accretion systems evolve toward synchronism at longer orbital periods.