Photometric analysis of the dwarf nova SU UMa based on TESS

TL;DR

This study analyzes TESS data of the dwarf nova SU UMa, revealing superhump evolution, estimating the mass ratio, and identifying quasiperiodic oscillations during different outburst states.

Contribution

First detailed photometric analysis of SU UMa using TESS data, including superhump evolution, mass ratio estimation, and QPO detection.

Findings

Superhump periods were determined for three stages of the superoutburst.

Mass ratio q=0.137 was estimated using stage A superhump data.

Ultralong period QPOs of 0.18, 0.19, and 0.285 days were identified in different states.

Abstract

We report the photometric analysis of SU UMa based on the observations of the Transiting Exoplanet Survey Satellite (TESS). TESS has released a large amount of data, which contains the light curves of a complete superoutburst and three normal outbursts of SU UMa. Based on the observations, the evolution of superhumps during the superoutburst was analyzed. By using the O - C method, the three stages were determined, and the superhump period for each stage was calculated. The mass ratio $q=0.137 (1)$ was estimated based on the stage A superhump method. A periodic oscillation with a period of 2.17(9) days was found in the superhump minimum O - C diagram, which is related to the precession of the accretion disk. We investigated the frequency information of quasiperiodic oscillations (QPOs) in the light curves. An ultralong period QPO of 0.18 days at the time of normal outburst and two ultralong periods QPOs of 0.19 days and 0.285 days in quiescence were found. No QPO was found in the superoutburst.