2004A&A...427..621S


Query : 2004A&A...427..621S

2004A&A...427..621S - Astronomy and Astrophysics, volume 427, 621-635 (2004/11-4)

Delays in dwarf novae II: VW Hyi, the tidal instability and enhanced mass transfer models.

SCHREIBER M.R., HAMEURY J.-M. and LASOTA J.-P.

Abstract (from CDS):

We discuss the multi-wavelength predictions of the two models proposed for SUUMa stars, i.e. the enhanced mass transfer (EMT) and the tidal thermal instability (TTI) models. We focus on the systematic differences of the suggested scenarios before discussing the model predictions together with the observations of the best-studied SU UMa system, VW Hyi. We find that assuming the standard form of the viscosity parameter α, both models predict only outbursts being triggered at the inner edge of the accretion disc. In the TTI model the superoutbursts are triggered when the outer radius of the disc reaches a certain value, i.e. the 3:1 resonance radius. In contrast, the EMT scenario predicts superoutbursts when the disc mass exceeds a critical value. This causes the EMT model to be much more sensitive to mass transfer variations than the TTI model. In both models we find the predicted UV and EUV delays in agreement with the observations of VW Hyi for αh/αc≲4. In addition both models can generate precursor outbursts which are more pronounced at short wavelengths, in agreement with observations. Variations found in the observed light curve of single systems (e.g. VW Hyi) as well as the difference between ordinary SU UMa stars and ER UMa systems are a natural outcome of the EMT model while the TTI model fails to explain them.

Abstract Copyright:

Journal keyword(s): accretion, accretion discs - instabilities - stars: dwarf novae - stars: novae, cataclysmic variables - stars: binaries: close - stars: individual: VW Hyi

Simbad objects: 10

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Number of rows : 10
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 V* VW Hyi CV* 04 09 11.3967378648 -71 17 41.554528260   12.786 12.543 14.160   ?+L0:e 633 0
2 V* TU Men CV* 04 41 40.7061732720 -76 36 45.942303384         14.057 ~ 153 0
3 V* SW UMa CV* 08 36 42.7492998216 +53 28 37.976599020           ~ 299 0
4 V* OY Car CV* 10 06 22.0793274312 -70 14 04.584660540           ~ 560 0
5 V* QZ Vir CV* 11 38 26.8241432424 +03 22 07.110298596     15.81     ~ 248 1
6 V* NY Ser CV* 15 13 02.2954585632 +23 15 08.407860084   15.648 15.699     ~ 68 0
7 V* ES Dra CV* 15 25 31.8170509152 +62 00 59.940328860   15.44       ~ 22 0
8 V* V405 Vul CV* 19 53 04.9219281768 +21 14 48.906501864           ~ 14 0
9 V* MN Dra CV* 20 23 38.1862508040 +64 36 26.592618240           ~ 43 1
10 V* SS Cyg CV* 21 42 42.8034497592 +43 35 09.867842484 11.07 12.651 12.032 9.326   K5V 1266 1

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2022.11.29-16:47:59

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