First discovery of QPOs in the dwarf nova HS 2325+8205 based on TESS photometry

TL;DR

This study reports the first detection of quasi-periodic oscillations (QPOs) in the dwarf nova HS 2325+8205 using TESS photometry, revealing a ~2160s QPO and its dependence on orbital phase, and refining the orbital period.

Contribution

First identification of QPOs in HS 2325+8205 and analysis of their relation to orbital phase using TESS data and multiple analysis methods.

Findings

Detected ~2160s QPOs in HS 2325+8205.

QPO amplitude varies with orbital phase.

Refined orbital period to 0.19433475 days.

Abstract

HS 2325+8205 is a long-period eclipsing dwarf nova with an orbital period above the period gap (Porb>3 h) and is reported to be a Z Cam-type dwarf nova. Based on the photometry of the Transiting Exoplanet Survey Satellite (TESS), the light variation and the quasi-periodic oscillation (QPOs) of HS 2325+8205 are studied. Using Continuous Wavelet Transform (CWT), Lomb-Scargle Periodogram (LSP), and sine fitting methods, we find for the first time that there is a QPOs of ~ 2160s in the long outburst top light curves of HS 2325+8205. Moreover, we find that the oscillation intensity of the QPOs of HS 2325+8205 is related to the orbital phase, and the intensity in orbital phases 0.5-0.9 are stronger than in orbital phases 0.1-0.5. Therefore, the relationship between the oscillation intensity of QPOs and the orbital phase may become a research window for the origin of QPOs. In addition, we use the LSP to correct the orbital period of HS 2325+8205 as 0.19433475(6) d.