Measuring the precise photometric period of the probable intermediate polar 1RXS J014549.6+514314 based on extensive photometry

Abstract

Recently, in the VSX database, G. Murawski reported the discovery of an oscillation with a period of about 40 min in the probable cataclysmic variable 1RXS J014549.6+514314. To confirm the existence of this oscillation and precisely measure its period, I conducted extensive photometric observations of the object over 25 nights between 2022 and 2024. The total duration of these observations was 139 hr. The observations revealed the oscillation on each observation night. This oscillation was coherent throughout all the observations covering 18 months. Due to the large coverage of observations, I was able to determine the oscillation period with high precision. It was found to be 41.485867+\-0.000026 min. The semi-amplitude of the oscillation was large, averaging 0.154(2) mag. The pulse profile of the oscillation did not change during the observations and followed a perfect sinusoidal pattern. With the high precision of the period, I created an ephemeris for the oscillation with a validity time of 30 years. This ephemeris can be used in future studies of changes in the oscillation period. Although short-period X-ray oscillations have not yet been detected in 1RXS J014549.6+514314, the high coherence of its 41-minute oscillation suggests that this object is most likely to be an intermediate polar.