Superoutbursts and Positive Superhumps Occurred During the Standstill of a Z Cam-type Dwarf Nova
arXiv:2412.17611 · doi:10.3847/1538-4357/adb7d9
Abstract
Dwarf novae are semi-detached binaries, where a white dwarf accretes material from a cool main-sequence companion via an accretion disk, and are known for their intermittent outbursts, making them key systems for studying accretion physics. The accumulation of large survey datasets has challenged traditional models, which assumed that the disk remains hot and cannot produce superoutbursts during the standstill of Z Cam-type dwarf nova and that superoutbursts require a mass ratio of . Here we report the detection of superoutbursts and positive superhumps (PSHs) during a standstill in the Z Cam-type star AT Cnc with a mass ratio larger than 0.33. Notably, the PSHs evolve gradually before the superoutburst begins, suggesting that an eccentric, precessing disk forms first, with the superoutburst occurring as the disk radius continues to expand. These findings provide the first detailed observational evidence of superoutbursts and PSHs occurring during standstill, offering important new insights into the classification of dwarf novae and the underlying mechanisms of outbursts
arXiv comment17 pages, 8 figures and 2 tables, accepted for publication in The Astrophysical Journal
References in corpus (34)
- The Transiting Exoplanet Survey Satellite
- The Zwicky Transient Facility: System Overview, Performance, and First Results
- The disc instability model of dwarf-novae and low-mass X-ray binary transients
- The first WASP public data release
- Superhumps in Cataclysmic Binaries. XXV. q_crit, epsilon(q), and Mass-Radius
- The ASAS-SN Catalog of Variable Stars II: Uniform Classification of 412,000 Known Variables
- Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae
- A review of the disc instability model for dwarf novae, soft X-ray transients and related objects
- Is evidence for enhanced mass transfer during dwarf-nova outbursts well substantiated?
- Testing the disk instability model of cataclysmic variables
- Study of Superoutbursts and Superhumps in SU UMa Stars by the Kepler Light Curves of V344 Lyrae and V1504 Cygni
- The precession of eccentric discs in close binaries
- AT Cnc: A Second Dwarf Nova with a Classical Nova Shell
- SPH Simulations of Negative (Nodal) Superhumps: A Parametric Study
- Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. VII: The Seventh Year (2014-2015)
- When does an old nova become a dwarf nova? Kinematics and age of the nova shell of the dwarf nova AT Cnc
- Anomalous Z Cam stars: a response to mass-transfer outbursts
- Late Superhumps in WZ Sge-Type Dwarf Novae
- Thermal-viscous instability in tilted accretion disks: a possible application to IW And-type dwarf novae
- TESS light curves of cataclysmic variables -- III -- More superhump systems among old novae and novalike variables
- Three Z Cam-Type Dwarf Novae Exhibiting IW And-Type Phenomenon
- The Eclipsing Accreting White Dwarf Z Chameleontis as Seen with TESS
- First discovery of QPOs in the dwarf nova HS 2325+8205 based on TESS photometry
- New evidence for the precession of tilted disk in SDSS J081256.85+191157.8
- BO Ceti: Dwarf Nova Showing Both IW And and SU UMa-Type Features
- Nine New Cataclysmic Variable Stars with Negative Superhumps
- ASASSN-18aan: An Eclipsing SU UMa-type Cataclysmic Variable with a 3.6-hour Orbital Period and a Late G-type Secondary Star
- Evolution of negative superhumps, quasi-periodic oscillations and outbursts in the Z Cam-type dwarf nova AH Her
- Discovery of Standstills in the SU UMa-Type Dwarf Nova NY Serpentis
- Investigation of superhumps in SU UMa-type dwarf novae based on the observations of TESS
- Coherent brightness modulations in the dwarf nova AT Cancri
- A New Window for Studying Intermediate Polars and Tilted Accretion Disk Precession
- Tilted Disk Precession and Negative Superhumps in HS 2325+8205: A Multi-Window Analysis
- A New IW And-Type Star: Karachurin 12 with Tilted Disks and Diverse cycles