Common Envelope Evolution and Formation of Cataclysmic Variables and Low-Mass X-ray Binaries

1992 ◽  
pp. 269-280 ◽  
Author(s):  
R. F. Webbink
Keyword(s):  
Cataclysmic Variables ◽  
X Ray ◽  
Common Envelope ◽  
Low Mass ◽  
X Ray Binaries

scholarly journals X-ray sources in Galactic globular clusters and old open clusters

2019 ◽  
Vol 14 (S351) ◽  
pp. 367-376
Author(s):  
Maureen van den Berg
Keyword(s):  
Globular Clusters ◽  
Cataclysmic Variables ◽  
Star Clusters ◽  
Open Clusters ◽  
Encounter Rate ◽  
X Ray ◽  
Low Mass ◽  
New Perspective ◽  
X Ray Binaries ◽  
Cluster Age

AbstractThe features and make up of the population of X-ray sources in Galactic star clusters reflect the properties of the underlying stellar environment. Cluster age, mass, stellar encounter rate, binary frequency, metallicity, and maybe other properties as well, determine to what extent we can expect a contribution to the cluster X-ray emission from low-mass X-ray binaries, millisecond pulsars, cataclysmic variables, and magnetically active binaries. Sensitive X-ray observations withXMM-Newton and certainlyChandra have yielded new insights into the nature of individual sources and the effects of dynamical encounters. They have also provided a new perspective on the collective X-ray properties of clusters, in which the X-ray emissivities of globular clusters and old open clusters can be compared to each other and to those of other environments. I will review our current understanding of cluster X-ray sources, focusing on star clusters older than about 1 Gyr, illustrated with recent results.

scholarly journals Theory of Accretion Disk Coronae

1990 ◽  
Vol 115 ◽  
pp. 187-196
Author(s):  
T. R. Kallman
Keyword(s):  
Active Galactic Nuclei ◽  
Accretion Disk ◽  
Cataclysmic Variables ◽  
Galactic Nuclei ◽  
X Ray ◽  
Spectral Signatures ◽  
Low Mass ◽  
X Ray Absorption ◽  
X Ray Binaries ◽  
Theoretical Issues

AbstractAccretion disk coronae are likely to be the dominant site for X-ray absorption and reprocessed emission in low mass X-ray binaries, and may be present in other classes of compact X-ray sources such as active galactic nuclei and cataclysmic variables. In spite of this fact, and in spite of the observational evidence for their existence, there remain many uncertainties about the structure of accretion disk coronae. This paper will discuss the coronal structure and dynamics, their X-ray spectral signatures including coupling to the variability behavior of compact X-ray sources, and the major unsolved theoretical issues surrounding them.

scholarly journals Observational Evidence for the Origin of X-ray Sources in Globular Clusters

2007 ◽  
Vol 3 (S246) ◽  
pp. 301-310 ◽  
Author(s):  
Frank Verbunt ◽  
Dave Pooley ◽  
Cees Bassa
Keyword(s):  
Statistical Method ◽  
Globular Clusters ◽  
Cataclysmic Variables ◽  
Observational Evidence ◽  
X Ray ◽  
Cluster Mass ◽  
Low Mass ◽  
Optical Identifications ◽  
X Ray Binaries

AbstractLow-mass X-ray binaries, recycled pulsars, cataclysmic variables and magnetically active binaries are observed as X-ray sources in globular clusters. We discuss the classification of these systems, and find that some presumed active binaries are brighter than expected. We discuss a new statistical method to determine from observations how the formation of X-ray sources depends on the number of stellar encounters and/or on the cluster mass. We show that cluster mass is not a proxy for the encounter number, and that optical identifications are essential in proving the presence of primordial binaries among the low-luminosity X-ray sources.

scholarly journals Modeling He-Rich Disks in AM CVn Binaries

2004 ◽  
Vol 194 ◽  
pp. 228-228
Author(s):  
T. Nagel ◽  
S. Dreizler ◽  
T. Rauch ◽  
K. Werner
Keyword(s):  
Accretion Disk ◽  
Time Scales ◽  
Accretion Disks ◽  
White Dwarf ◽  
Cataclysmic Variables ◽  
X Ray ◽  
Synthetic Spectra ◽  
Pure Helium ◽  
Low Mass ◽  
X Ray Binaries

We have developed a new code for the calculation of synthetic spectra and vertical structures of accretion disks in cataclysmic variables and compact X-ray binaries. Here we present results for the CV system AM CVn.AM CVn stars are a special type of cataclysmic variables, also called helium cataclysmics. They are systems of interacting binary white dwarfs, consisting of a degenerate C-O white dwarf primary and a low mass semi-degenerate secondary. The secondary loses mass, almost, pure helium, to the primary, forming an accretion disk. They have all in common a helium-rich composition, analoguous to the hydrogen-rich cataclysmic variables. They show photometric variabilities on time scales of ~ 1000s, the prototype of the class, AM CVn, e.g. exhibits a variability of ~ 18 min (Nelemans et al. 2001).

scholarly journals Monitoring of X-Ray Sources in the Optical Spectral Region

2010 ◽  
Vol 2010 ◽  
pp. 1-12
Author(s):  
Vojtěch Šimon
Keyword(s):  
Gamma Ray ◽  
Cataclysmic Variables ◽  
Physical Processes ◽  
X Ray ◽  
Low Mass ◽  
Intermediate Polars ◽  
Photometric Monitoring ◽  
The Individual ◽  
X Ray Binaries ◽  
Review Current

We review current results and perspectives of the photometric monitoring of the optical counterparts of X-ray sources of various kinds (binary X-ray sources (cataclysmic variables and low-mass X-ray binaries, supersoft X-ray sources, microquasars), gamma-ray bursts). We discuss the problems of the monitoring of the individual kinds of objects in the optical and X-ray passbands. We show the importance of multifilter monitoring to obtain a deeper understanding of the physical processes and to resolve between the individual emission mechanisms. We also show that there are brief, unique, and little understood phenomena which are very promising targets for the optical monitoring, for example, flares in intermediate polars.

scholarly journals Common-Envelope Evolution, the Formation of CVs, LMXBs, and the Fate of HMXBs

1996 ◽  
Vol 165 ◽  
pp. 3-15 ◽  
Author(s):  
R.E. Taam
Keyword(s):  
Time Scale ◽  
Three Dimensional ◽  
Cataclysmic Variables ◽  
Theoretical Description ◽  
High Mass ◽  
X Ray ◽  
Common Envelope ◽  
The Common ◽  
Binary Evolution ◽  
X Ray Binaries

Recent three-dimensional studies of the common-envelope phase of binary evolution have provided important insights into its theoretical description. The role of non-axisymmetric effects associated with gravitational torques is essential for understanding all aspects of the evolution. For successful ejection of the common envelope and survival of the remnant compact binary it is required that the orbital period of the progenitor system is long, so that one of the components of the system is in the red giant or red supergiant stage of evolution. Not only must there be sufficient energy released from the orbit to unbind the common envelope, but it is also necessary that a sufficiently steep density gradient exist above the evolved core of the giant. If these conditions are satisfied, the time scale for orbital decay in the region above the core exceeds the time scale for mass loss from the common envelope and merger is avoided. The implications of these results for the formation of cataclysmic variables (CVs), low-mass X-ray binaries (LMXBs), and the descendants of high-mass X-ray binaries (HMXBs) are discussed.

scholarly journals Formation of Binary and Millisecond Pulsars: Puzzles and Possible Solutions

2012 ◽  
Vol 8 (S291) ◽  
pp. 499-501
Author(s):  
Yong Shao ◽  
Xiang-Dong Li
Keyword(s):  
Mass Transfer ◽  
Neutron Stars ◽  
Systematic Study ◽  
Brown Dwarf ◽  
Millisecond Pulsars ◽  
X Ray ◽  
Common Envelope ◽  
Binary Pulsars ◽  
Low Mass ◽  
X Ray Binaries

AbstractWe present a systematic study of the evolution of intermediate- and low-mass X-ray binaries. Our calculations suggest that millisecond binary pulsars in wide orbits might have neutron stars born massive, or been formed through mass transfer driven by planet/brown dwarf-involved common envelope evolution.

scholarly journals A MeerKAT survey of nearby nova-like cataclysmic variables

2020 ◽  
Vol 496 (3) ◽  
pp. 2542-2557 ◽  
Author(s):  
D M Hewitt ◽  
M L Pretorius ◽  
P A Woudt ◽  
E Tremou ◽  
J C A Miller-Jones ◽  
...  
Keyword(s):  
Radio Emission ◽  
Cataclysmic Variables ◽  
Spectral Energy ◽  
Energy Distributions ◽  
Transfer Rates ◽  
X Ray ◽  
System Parameters ◽  
Radio Detection ◽  
Low Mass ◽  
X Ray Binaries

ABSTRACT We present the results of MeerKAT radio observations of 11 nearby nova-like cataclysmic variables (CVs). We have detected radio emission from IM Eri, RW Sex, V3885 Sgr, and V603 Aql. While RW Sex, V3885 Sgr, and V603 Aql had been previously detected, this is the first reported radio detection of IM Eri. Our observations have doubled the sample of non-magnetic CVs with sensitive radio data. We observe that at our radio detection limits, a specific optical luminosity ${\gtrsim}2.2\times 10^{18}\,$ erg s−1 Hz−1 (corresponding to MV ≲ 6.0) is required to produce a radio detection. We also observe that the X-ray and radio luminosities of our detected nova-like CVs are on an extension of the $L_X\propto L_R^{\sim 0.7}$ power law originally proposed for non-pulsating neutron star low-mass X-ray binaries. We find no other correlations between the radio emission and emission in other wavebands or any other system parameters for the existing sample of radio-detected non-magnetic CVs. We measure in-band (0.9–1.7 GHz) radio spectral indices that are consistent with reports from earlier work. Finally, we constructed broad spectral energy distributions for our sample from published multiwavelength data, and use them to place constraints on the mass transfer rates of these systems.

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