Detection of the secondary star in the eclipsing cataclysmic variable AC CANCRI

1982 ◽  
Vol 94 ◽  
pp. 950 ◽  
Author(s):  
R. A. Downes
Keyword(s):  
Cataclysmic Variable ◽  
Secondary Star

scholarly journals Hydrodynamic Modeling of Mass Loss from Cataclysmic Variable Secondaries

1980 ◽  
Vol 58 ◽  
pp. 641-642
Author(s):  
Ronald L. Gilliland
Keyword(s):  
Mass Loss ◽  
Small Region ◽  
Stellar Structure ◽  
Approximation Schemes ◽  
Cataclysmic Variable ◽  
Spherically Symmetric ◽  
Lagrangian Point ◽  
Secondary Star ◽  
Equipotential Surfaces ◽  
Detailed Computer

AbstractResults of detailed computer simulations of mass loss from a cataclysmic variable secondary are presented. The calculations involve solution of the nonlinear hydrodynamical equations of stellar structure under varying degrees of approximation in an attempt to determine stability of the mass loss process. For comparison with previous theoretical studies dynamical sequences were computed assuming spherically symmetric mass loss from the secondary. The assumption of spherical symmetry is very poor since nearly all of the transferred material is lost within a small region about the inner Lagrangian point. Dynamical sequences treating only the region near the Lagrangian point were constructed in a manner consistent with the assumption of Roche geometry. Finally the effects of mass flow nonorthogonal to the Roche equipotential surfaces were treated in a very simple way. The last generalization produces stable mass loss in a model which was unstable for the less realistic approximation schemes. The finding of stable mass transfer implies that instability of the secondary star is not the mechanism leading to cataclysmic variable outbursts. This conclusion is consistent with published observations of dwarf novae made just prior to outburst.

scholarly journals Emission from the Secondary Star in the Old Cataclysmic Variable WZ Sagittae

2001 ◽  
Vol 562 (2) ◽  
pp. L145-L148 ◽  
Author(s):  
D. Steeghs ◽  
T. Marsh ◽  
C. Knigge ◽  
P. F. L. Maxted ◽  
E. Kuulkers ◽  
...  
Keyword(s):  
Cataclysmic Variable ◽  
Secondary Star

scholarly journals KIC 9406652: A laboratory for tilted disks in cataclysmic variable stars

2020 ◽  
Vol 72 (6) ◽  
Author(s):  
Mariko Kimura ◽  
Yoji Osaki ◽  
Taichi Kato
Keyword(s):  
Cataclysmic Variables ◽  
Orbital Plane ◽  
Variable Stars ◽  
Bright Spot ◽  
Cataclysmic Variable ◽  
Secondary Star ◽  
Orbital Phase ◽  
Rich Information ◽  
Long Timescales ◽  
Tilted Disk

Abstract KIC 9406652 is a cataclysmic variable, sub-classified as an “IW And-type” star, which shows repeated standstills with oscillatory variations terminated by brightening. This system shows negative superhumps, semi-periodic variations having periods slightly shorter than the ∼6 hr orbital period, and super-orbital signals having ∼4 d periods, both of which are believed to originate from a precessing, tilted accretion disk. We have re-examined its Kepler light curve over 1500 d. In accordance with a cycle of IW And-type light variation, the frequency of negative superhumps showed reproducible variation: a rapid drop during the brightening and a gradual increase during the standstill. This is interpreted as a drastic change in the radial mass distribution and the expansion of the tilted disk, which is not expected from the existing models of IW And stars. The constancy in flux amplitudes of the negative superhumps confirms that their light source is the bright spot sweeping across the surface of the tilted disk. The frequencies of the negative superhumps and super-orbital signals varied in unison on long timescales, suggesting their common origin: the tilted disk. The orbital signals at the brightening were dominated by the irradiation of the secondary star and varied with the orientation of the tilted disk; the amplitude was maximized at the minimum of the super-orbital signals, and the light maximum shifted to early orbital phases as the super-orbital phase advanced. This is the first direct evidence that the disk is tilted out of the binary orbital plane and is retrogradely precessing. The tilt angle of the disk inferred from semi-amplitudes of super-orbital signals was lower than 3°. The diversity in light curves of the negative superhumps supports this and suggests that part of the gas stream overflows the disk edge. This study thus offers rich information about the tilted disk in cataclysmic variables.

scholarly journals On the secondary star of the cataclysmic variable 1RXS J094432.1+035738

2002 ◽  
Vol 383 (3) ◽  
pp. 933-937 ◽  
Author(s):  
R. E. Mennickent ◽  
G. Tovmassian ◽  
S. V. Zharikov ◽  
C. Tappert ◽  
J. Greiner ◽  
...  
Keyword(s):  
Cataclysmic Variable ◽  
Secondary Star

Flares and Flickering in the Cataclysmic Variable AE Aquarii

1995 ◽  
Vol 151 ◽  
pp. 278-279
Author(s):  
William F. Welsh ◽  
Keith Horne ◽  
Richard Gomer
Keyword(s):  
Time Resolution ◽  
Cataclysmic Variable ◽  
Mass Ratio ◽  
Stellar Flare ◽  
Secondary Star ◽  
Spectrophotometric Data ◽  
Γ Ray ◽  
The Individual ◽  
Stellar Masses ◽  
Optical Flare

Detected from the radio to the γ-ray bands, AE Aquarii is an extraordinary cataclysmic variable. It is a relatively bright (V ∼11.4), non-eclipsing binary with an orbital period of 9h.9. The mass-donor secondary star is of approximate spectral type K5V and contributes about ∼ 80% of the total flux in the optical. While the mass ratio is well determined at q = M2/M1 = 0.646, the individual stellar masses are poorly known since the inclination is unknown. AE Aqr’s flickering behavior is unique among CVs, alternating from periods of very violent activity to near total quiescence. Large amplitude flares have been detected in the radio, optical and UV. Previous work has shown the optical flare spectrum to be similar to stellar flare spectra.Four nights of exactly simultaneous Hα spectroscopy and photometry were obtained on the 2.5 and 1.5m telescopes at Mt. Wilson on 27-30 July 1982. The simultaneity allowed us to renomalize the spectroscopy to agree with the photometry, giving us spectrophotometric data (spectral resolution ∼ 50 km s−, time resolution ∼ 68). A total of ∼ 17h of data were obtained, resulting in 10,098 spectra.

scholarly journals A Stellar Constraint on Eddington-inspired Born–Infeld Gravity from Cataclysmic Variable Binaries

2022 ◽  
Vol 924 (1) ◽  
pp. 20
Author(s):  
Pritam Banerjee ◽  
Debojyoti Garain ◽  
Suvankar Paul ◽  
Rajibul Shaikh ◽  
Tapobrata Sarkar
Keyword(s):  
General Relativity ◽  
Modified Gravity ◽  
Cataclysmic Variable ◽  
Energy Limit ◽  
Tidal Disruption ◽  
Classical Level ◽  
Secondary Star ◽  
Modified Gravity Theory ◽  
End Stage ◽  
Collapse Process

Abstract Eddington-inspired Born–Infeld gravity is an important modification of Einstein’s general relativity, which can give rise to nonsingular cosmologies at the classical level, and avoid the end-stage singularity in a gravitational collapse process. In the Newtonian limit, this theory gives rise to a modified Poisson’s equation, as a consequence of which stellar observables acquire model dependent corrections, compared to the ones computed in the low energy limit of general relativity. This can in turn be used to establish astrophysical constraints on the theory. Here, we obtain such a constraint using observational data from cataclysmic variable binaries. In particular, we consider the tidal disruption limit of the secondary star by a white dwarf primary. The Roche lobe filling condition of this secondary star is used to compute stellar observables in the modified gravity theory in a numerical scheme. These are then contrasted with the values obtained by using available data on these objects, via a Monte Carlo error progression method. This way, we are able to constrain the theory within the 5σ confidence level.

The Eclipsing Cataclysmic Variable V347 Puppis Revisited

1999 ◽  
Vol 523 (2) ◽  
pp. 786-796 ◽  
Author(s):  
Marcos P. Diaz ◽  
Ivan Hubeny
Keyword(s):  
Cataclysmic Variable

scholarly journals The effect of photoionizing feedback on the shaping of hierarchically-forming stellar clusters

2020 ◽  
Vol 499 (1) ◽  
pp. 668-680
Author(s):  
Alejandro González-Samaniego ◽  
Enrique Vazquez-Semadeni
Keyword(s):  
Star Formation ◽  
Early Stage ◽  
Stellar Clusters ◽  
Low Mass Stars ◽  
Transfer Scheme ◽  
Star Forming ◽  
Secondary Star ◽  
Low Mass ◽  
Hydrodynamical Simulations ◽  
Formation Efficiency

ABSTRACT We use two hydrodynamical simulations (with and without photoionizing feedback) of the self-consistent evolution of molecular clouds (MCs) undergoing global hierarchical collapse (GHC), to study the effect of the feedback on the structural and kinematic properties of the gas and the stellar clusters formed in the clouds. During this early stage, the evolution of the two simulations is very similar (implying that the feedback from low-mass stars does not affect the cloud-scale evolution significantly) and the star-forming region accretes faster than it can convert gas into stars, causing the instantaneous measured star formation efficiency (SFE) to remain low even in the absence of significant feedback. Afterwards, the ionizing feedback first destroys the filamentary supply to star-forming hubs and ultimately removes the gas from it, thus first reducing the star formation (SF) and finally halting it. The ionizing feedback also affects the initial kinematics and spatial distribution of the forming stars because the gas being dispersed continues to form stars, which inherit its motion. In the non-feedback simulation, the groups remain highly compact and do not mix, while in the run with feedback, the gas dispersal causes each group to expand, and the cluster expansion thus consists of the combined expansion of the groups. Most secondary star-forming sites around the main hub are also present in the non-feedback run, implying a primordial rather than triggered nature. We do find one example of a peripheral star-forming site that appears only in the feedback run, thus having a triggered origin. However, this appears to be the exception rather than the rule, although this may be an artefact of our simplified radiative transfer scheme.

scholarly journals Spectroscopy and Optical/IR Photometry of the Cataclysmic Variable CPD-48° 1577

1984 ◽  
Vol 80 ◽  
pp. 145-151
Author(s):  
W. Wargau ◽  
A. Bruch ◽  
H. Drechsel ◽  
J. Rahe ◽  
R. Schoembs
Keyword(s):  
Emission Line ◽  
Cataclysmic Variable ◽  
Line Profiles ◽  
Photometric Variability ◽  
Ir Photometry

AbstractThe photometric variability of CPD-48°1577 in the optical and IR ranges is discussed. The structure and variation of prominent emission line profiles are investigated. An estimate of the distance is given.

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