scholarly journals Orbital properties of an unusually low-mass sdB star in a close binary system with a white dwarf

2012 ◽  
Vol 424 (3) ◽  
pp. 1752-1761 ◽  
Author(s):  
R. Silvotti ◽  
R. H. Østensen ◽  
S. Bloemen ◽  
J. H. Telting ◽  
U. Heber ◽  
...  
Keyword(s):  
Binary System ◽  
White Dwarf ◽  
Close Binary System ◽  
Close Binary ◽  
Low Mass

scholarly journals Marginally low mass ratio close binary system V1191 Cyg

New Astronomy ◽  
2012 ◽  
Vol 17 (1) ◽  
pp. 46-49 ◽  
Author(s):  
B. Ulaş ◽  
B. Kalomeni ◽  
V. Keskin ◽  
O. Köse ◽  
K. Yakut
Keyword(s):  
Binary System ◽  
Close Binary System ◽  
Close Binary ◽  
Mass Ratio ◽  
Low Mass ◽  
Low Mass Ratio

scholarly journals Recurrence of Nova Explosions

1979 ◽  
Vol 53 ◽  
pp. 525-525 ◽  
Author(s):  
Kyoji Nariai ◽  
Ken’ichi Nomoto
Keyword(s):  
Binary System ◽  
White Dwarf ◽  
Close Binary System ◽  
Roche Lobe ◽  
Close Binary ◽  
Ignition Point ◽  
Almost All

It has been shown by many computations that a nova explosion is triggered by mass accretion onto a white dwarf in a close binary system. Such nova explosions will recur many times in the following way. When a certain amount of hydrogen-rich gas has been accreted on the white dwarf, a hydrogen-shell flash is ignited. Then the hydrogen-rich envelope expands greatly, which, in some cases, grows into a nova explosion. Almost all envelope mass is ejected into space or at least overflows its Roche lobe. After that the mass of the envelope increases again by accretion and the shell flash is ignited again. The period of such recurrence is given by τrec = ΔMH/(dM/dt), where dM/dt and ΔMH are the rate of accretion and the mass contained in the hydrogen-rich envelope at the ignition point.

scholarly journals ON THE CHROMOSPHERIC ACTIVITY NATURE OF A LOW-MASS CLOSE BINARY: KIC 12004834

2019 ◽  
Vol 55 (1) ◽  
pp. 73-92
Author(s):  
E. Yoldaş ◽  
H. A. Dal
Keyword(s):  
Binary System ◽  
Close Binary System ◽  
Close Binary ◽  
Flare Activity ◽  
Mass Ratio ◽  
Orbital Inclination ◽  
Chromospheric Activity ◽  
Low Mass ◽  
High Level ◽  
Flare Frequency

We study the nature of the chromospheric activity of an eclipsing binary KIC 12004834, using Kepler data. We analyse the light curve of the system, the sinusoidal variations at out-of-eclipses and detected flare events. The secondary component’s temperature is found to be 4001±11 K, the mass ratio is 0.743±0.001, and the orbital inclination is 75◦.89±0◦.03. The analysis indicates a stellar spot effect on the variation. Moreover, the OPEA model has been derived over 149 flares. The saturation level called Plateau value, is found to be 2.093±0.236 s. The flare number per hour (known as flare frequency N1) is found to be 0.06644 h−1, while the flare-equivalent duration per hour (known as flare frequency N2) is found to be 0.59 second/hour. According to these results, KIC 12004834 is a very low-mass close binary system with high level of flare activity.

scholarly journals The Central Star of the Planetary Nebula LMC-N66: A Massive Accreting White Dwarf?

2004 ◽  
Vol 194 ◽  
pp. 41-43
Author(s):  
M. Реñа ◽  
W.-R. Hamann
Keyword(s):  
Binary System ◽  
White Dwarf ◽  
Planetary Nebula ◽  
Massive Star ◽  
Initial Conditions ◽  
Central Star ◽  
Close Binary System ◽  
Close Binary ◽  
Recent Analysis ◽  
Bolometric Luminosity

AbstractThe central star of the PN LMC-N66 showed an impressive outburst in 1993 - 1994, returning to its initial conditions about 8 years later. Its spectrum resembles that of a WN4.5 star, being the only confirmed central star of planetary nebulae showing such a spectral type. Recent analysis for the central star parameters, performed by Hamann et al. (2003) is presented. They have found that the bolometric luminosity increased by a factor larger than 6, during the outburst. We discuss the possible scenarios which have been proposed to explain the exceptional stellar parameters and the outburst mechanism. The stellar characteristics and the morphology and kinematics of the planetary nebula suggest the presence of binary system (massive star with a less massive companion or, a white dwarf accreting matter in a close-binary system). These cases pose the least severe contradictions with observational constraints.

scholarly journals Collapse of Accreting White Dwarf to Form a Neutron Star

1979 ◽  
Vol 53 ◽  
pp. 56-60 ◽  
Author(s):  
Ken’ichi Nomoto ◽  
Shigeki Miyaji ◽  
Daiichiro Sugimoto ◽  
Koichi Yokoi
Keyword(s):  
Neutron Star ◽  
Binary System ◽  
Mass Exchange ◽  
White Dwarf ◽  
Mass Range ◽  
Close Binary System ◽  
Roche Lobe ◽  
Close Binary ◽  
Primary Star ◽  
Companion Star

AbstractIn a close binary system with a primary star in the mass range 8-12 M⊙, the primary star leaves a white dwarf composed of 16O, 20Ne, and 24Mg as a result of mass exchange. When the companion star, fills its Roche lobe, overflowing matter accretes onto the white dwarf. We have computed the evolution of such an accreting O-Ne-Mg white dwarf and found that electron captures on 24Mg and 20Ne trigger the collapse when the mass reaches 1.38 M⊙. As a result of the collapse, oxygen begins to deflagrate but the effects of electron captures dominate over the oxygen deflagration. The white dwarf collapses to form a neutron star.

Gravitational Radiation and the Evolution of Low Mass Binaries

1976 ◽  
Vol 73 ◽  
pp. 193-204 ◽  
Author(s):  
John Faulkner
Keyword(s):  
Mass Transfer ◽  
Angular Momentum ◽  
Binary System ◽  
Observational Study ◽  
Gravitational Radiation ◽  
Region Of Interest ◽  
Close Binary System ◽  
Close Binary ◽  
Theoretical Studies ◽  
Low Mass

Gravitational radiation of energy and angular momentum can modify and in some cases, control the evolution of a close binary system. The region of interest is briefly delineated. Recent work of the author and colleagues of relevance to this area is discussed, including theoretical studies of accretion, mass loss and mass transfer, and an observational study of a system, HZ 29 where gravitational radiation may dictate its behaviour.

scholarly journals X-ray and UV emission of the ultrashort-period, low-mass eclipsing binary system BX Trianguli

2018 ◽  
Vol 619 ◽  
pp. A138
Author(s):  
V. Perdelwitz ◽  
S. Czesla ◽  
J. Robrade ◽  
T. Pribulla ◽  
J. H. M. M. Schmitt
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Binary Systems ◽  
Uv Light ◽  
Close Binary ◽  
Eclipsing Binary ◽  
X Ray ◽  
Uv Emission ◽  
Low Mass ◽  
Orbital Modulation

Context.Close binary systems provide an excellent tool for determining stellar parameters such as radii and masses with a high degree of precision. Due to the high rotational velocities, most of these systems exhibit strong signs of magnetic activity, postulated to be the underlying reason for radius inflation in many of the components. Aims.We extend the sample of low-mass binary systems with well-known X-ray properties. Methods.We analyze data from a singular XMM-Newton pointing of the close, low-mass eclipsing binary system BX Tri. The UV light curve was modeled with the eclipsing binary modeling tool PHOEBE and data acquired with the EPIC cameras was analyzed to search for hints of orbital modulation. Results.We find clear evidence of orbital modulation in the UV light curve and show that PHOEBE is fully capable of modeling data within this wavelength range. Comparison to a theoretical flux prediction based on PHOENIX models shows that the majority of UV emission is of photospheric origin. While the X-ray light curve does exhibit strong variations, the signal-to-noise ratio of the observation is insufficient for a clear detection of signs of orbital modulation. There is evidence of a Neupert-like correlation between UV and X-ray data.

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