Evolution of negative superhumps, quasi-periodic oscillations and outbursts in the Z Cam-type dwarf nova AH Her
arXiv:2309.05891 · doi:10.3847/1538-4357/ace183
Abstract
AH Her is a Z Cam-type dwarf nova with an orbital period of ~ 0.258 d. Dwarf nova oscillations and long-period dwarf nova oscillations have been detected, but no quasi-periodic oscillations (QPOs) and negative superhumps (NSHs) have been found. We investigated the association between NSHs, QPOs, and outbursts of AH Her based on \textit{TESS} photometry. We find for the first time the NSHs with a period of 0.24497(1) d in AH Her, and trace the variation of the amplitude and period of NSHs with the outburst. The amplitude of the NSHs is most significant at quiescence, weakening as the outburst rises, becoming undetectable at the top, rebounding and weakening at the plateau, and strengthening again as the outburst declines. The variation of the accretion disk radius can explain the NSHs amplitude variation except for the plateau, so we suggest that the relationship between NSHs amplitude and outburst can be used as a window to study the accretion disk instability and the origin of NSHs. In addition, we find the periodic variations in the amplitude, maxima, and shape of the NSHs ranging from 2.33(2) d to 2.68(5) d, which may be related to the precession of the tilted disk. Finally, we find QPOs at the top of AH Her's long outburst with ~ 2800 s similar to HS 2325+8205, suggesting that the presence of QPOs at the top of Z Cam's long outburst may be a general phenomenon
20 pages, 11 figures, accepted for publication in the Astrophysical Journal
References in corpus (8)
- The Transiting Exoplanet Survey Satellite
- Dwarf nova oscillations and quasi-periodic oscillations in cataclysmic variables -- V. Results from an extensive survey
- TESS light curves of cataclysmic variables I -- Unknown periods in long-known stars
- KIC 9406652: A laboratory of the tilted disk in cataclysmic variable stars
- First discovery of QPOs in the dwarf nova HS 2325+8205 based on TESS photometry
- EX Draconis: Using Eclipses to Separate Outside-In and Inside-Out Outbursts
- QPOs in compact binaries from small scale eruptions in an inner magnetized disk
- New radial velocity observations of AH Her: evidence for material outside the tidal radius