2025ApJ...982..127S

Query : 2025ApJ...982..127S

2025ApJ...982..127S - Astrophys. J., 982, 127 (2025/April-1)

Superoutbursts and Positive Superhumps Occurred during the Standstill of a Z Cam-type Dwarf Nova.

SUN Q.-B., QIAN S.-B., ZHU L.-Y., LI Q.-M., LI F.-X., LI M.-Y. and LI P.

Abstract (from CDS):

Dwarf novae (DNe) are semidetached 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 data sets has challenged traditional models, which assumed that the disk remains hot and cannot produce superoutbursts during the standstill of a Z Camelopardalis (Z Cam)-type DN and that superoutbursts require a mass ratio of q = M2/M1 ≤ 0.25-0.33. 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 DNe and the underlying mechanisms of outbursts.

Abstract Copyright: © 2025. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Binary stars - Cataclysmic variable stars - Dwarf novae - Z Camelopardalis stars - SU Ursae Majoris stars

Simbad objects: 1

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Number of rows : 1
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 V* AT Cnc CV* 08 28 36.9270732360 +25 20 03.045311628   14.798 14.583 13.690   DAe: 129 0

Query : 2025ApJ...982..127S

Basic data :
V* AT Cnc -- Cataclysmic Binary
Other object types: otypes_help 		V* (ASASSN,1SWASP,...), * (GJ,GSC,...), CV* (2009yCat), G (Mrk,UGCA), MIR (WISEA,WISE), Opt (LAMOST,SDSS), WD* (1977ApJ), blu (Ton), X (1eRASS), NIR (2MASS), ev (ZTF)
ICRS coord. (ep=J2000) : 		08 28 36.9270732360 +25 20 03.045311628 (Optical) [ 0.0286 0.0207 90 ] A 2020yCat.1350....0G
FK4 coord. (ep=B1950 eq=1950) : 		08 25 37.7746982308 +25 30 02.894914959 [ 0.0286 0.0207 90 ]
Gal coord. (ep=J2000) : 		198.5482589682938 +31.7398089587943 [ 0.0286 0.0207 90 ]
Proper motions mas/yr : 		-4.188 2.971 [0.033 0.024 90] A 2020yCat.1350....0G
Parallaxes (mas): 		2.1489 [0.032] A 2020yCat.1350....0G
Spectral type: 		DAe: D 1977ApJ...218L..21G
Fluxes (12) :
B 14.798 [0.39] D 2012yCat.1322....0Z
V 14.583 [0.32] D 2012yCat.1322....0Z
R 13.690 [0.06] E 2012yCat.1322....0Z
G 14.6926 [0.0111] C 2018yCat.1345....0G
J 12.482 [0.021] C 2003yCat.2246....0C
H 12.328 [0.023] C 2003yCat.2246....0C
K 12.236 [0.023] C 2003yCat.2246....0C
u (AB) 13.861 [0.003] C 2006ApJS..162...38A
g 14.679 [0.40] D 2012yCat.1322....0Z
r 14.547 [0.30] D 2012yCat.1322....0Z
i 14.385 [0.28] D 2012yCat.1322....0Z
z (AB) 13.707 [0.004] C 2006ApJS..162...38A
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Identifiers (22) :
An access of full data is available using the icon Vizier near the identifier of the catalogue

SV* GR 151 2MASS J08283691+2520030 Ton 323 ZTF17aaagvsz
ASASSN-V J082836.99+252002.8 Mrk 388 UCAC2 40684326 AAVSO 0822+25
1eRASS J082836.7+251952 SDSS J082836.92+252003.0 UGCA 139 Gaia DR3 679528804789642240
GJ 2068 SV* SON 323 V* AT Cnc Gaia DR2 679528804789642240
GSC 01944-01001 1SWASP J082836.92+252003.2 WISEA J082836.92+252003.1
LAMOST J082836.91+252003.0 TIC 3645653 WISE J082836.92+252003.2

References (129 between 1850 and 2026) (Total 129)
Simbad bibliographic survey began in 1850 for stars (at least bright stars) and in 1983 for all other objects (outside the solar system).
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Collections of Measurements Description of Measurements

Velocities : 1    Distance : 4    Plx : 2    PM : 2    SpT : 1   

   

External archives :

Archive data at HEASARC - High-Energy Astrophysics Science Archive Research Center

Data at NED - NASA/IPAC Extragalactic Database : V* AT Cnc

Link by name to the catalogue in VizieR :

GJ 2068 GSC 01944-01001 2MASS J08283691+2520030 SDSS J082836.92+252003.0 UCAC2 40684326
V* AT Cnc WISEA J082836.92+252003.1 WISE J082836.92+252003.2 Gaia DR3 679528804789642240 Gaia DR2 679528804789642240

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