scholarly journals A deep, unusual over-contact binary system with high rate of mass transfer: LP Ursa Major

2015 ◽  
Vol 67 (3) ◽  
pp. 48 ◽  
Author(s):  
Wen-Ping Liao ◽  
Sheng-Bang Qian ◽  
Er-Gang Zhao ◽  
Lin-Jia Li
Keyword(s):  
Mass Transfer ◽  
Binary System ◽  
High Rate ◽  
Contact Binary

Modeling Mass Transfer in Biological Wastewater Treatment Processes

1986 ◽  
Vol 18 (6) ◽  
pp. 35-45 ◽  
Author(s):  
John C. Kissel
Keyword(s):  
Mass Transfer ◽  
Computer Simulation ◽  
Wastewater Treatment ◽  
Biological Treatment ◽  
Process Models ◽  
High Rate ◽  
Biological Wastewater Treatment ◽  
Trickling Filter ◽  
Treatment Processes ◽  
Individual Effects

Parameters characterizing intrasolid, liquid/solid, and gas/liquid mass transport phenomena in biological treatment systems are required if mass transfer is to be included in process models. Estimates of such parameters are presented and discussed. Collective and individual effects of mass transfer resistances are illustrated by computer simulation of a high-rate trickling filter.

scholarly journals Variability of the Light Curves of the Close Binary GR Tauri

2002 ◽  
Vol 187 ◽  
pp. 337-338
Author(s):  
A. Yamasaki ◽  
M. Takeda ◽  
T. Yamauchi ◽  
G. Takada ◽  
S. Hattori
Keyword(s):  
Binary System ◽  
The State ◽  
Light Curves ◽  
Close Binary ◽  
Eclipsing Binary ◽  
Short Period ◽  
Contact Binary

AbstractVariability of the light curves of the short-period eclipsing binary system GR Tau (, almost-contact binary) is studied. It is found that GR Tau experienced both the state which is characterized by asymmetric light curves and the state characterized by symmetrical light curves.

scholarly journals A Model for R Aqr from HST

1992 ◽  
Vol 151 ◽  
pp. 425-428
Author(s):  
Denis Burgarella ◽  
Manfred Vogel ◽  
Francesco Paresce
Keyword(s):  
Mass Transfer ◽  
Binary System ◽  
High Spatial Resolution ◽  
Ambient Medium ◽  
Spherically Symmetric ◽  
Symbiotic Star ◽  
Radiative Shock ◽  
Giant Star ◽  
The Core ◽  
Stellar Source

High spatial resolution observations R Aqr have been carried out with the HST/FOC. R Aqr is the nearest symbiotic star, i.e. an interacting system consisting of a cool giant star and a hot ionizing source embedded in a larger and complex nebula. We suggest, here, that the binary system is composed of a Mira and a hot stellar source with a radiation temperature of T* ≈ 40 000 K, a luminosity of L ≈ 10L⊙ and a radius R ≲ 0.1 R⊙. Mass transfer between the two components of the system occurs via capture of the Mira wind. Of the plausible mechanisms that may produce the R Aqr jet, an accretion/ejection scenario or the collision of winds seem to be unlikely, but spectral observations of the core are needed to conclude. Another possible origin is based on a spherically symmetric stellar wind that sweeps out a cavity in an ambient medium. This bubble elongates in the directions of least resistance, and matter eventually flows out through two symmetric nozzles. Comparison with models shows that the emission in the NE and SW outer features of the jets is due to a radiative shock but the pre-shock gas must be partially photoionized by the central hot stellar source.

The contact binary system YY Eri

1996 ◽  
Vol 246 (2) ◽  
pp. 229-242 ◽  
Author(s):  
E. Budding ◽  
C-H. Kim ◽  
O. Demircan ◽  
Z. Müyesseroğlu ◽  
K. Saijo ◽  
...  
Keyword(s):  
Binary System ◽  
Contact Binary

Mass transfer dynamics of ammonia in high rate biomethanation of poultry litter leachate

2012 ◽  
Vol 109 ◽  
pp. 234-238 ◽  
Author(s):  
A. Gangagni Rao ◽  
Bharath Gandu ◽  
Y.V. Swamy
Keyword(s):  
Mass Transfer ◽  
Poultry Litter ◽  
High Rate ◽  
Litter Leachate

scholarly journals The Variable Ṁ Scenario for Nova Outbursts

1987 ◽  
Vol 93 ◽  
pp. 419-429
Author(s):  
A. Kovetz ◽  
D. Prialnik ◽  
M.M. Shara
Keyword(s):  
Mass Transfer ◽  
High Rate ◽  
Transfer Rates ◽  
Classical Novae ◽  
Binary Separation ◽  
Classical Nova ◽  
The One ◽  
Thermonuclear Runaway ◽  
Mass Ejection ◽  
Nova Outbursts

AbstractAn evolutionary scenario for classical novae is proposed, which is intended to solve the discrepancies that exist between theory and observations: the space densities of classical novae deduced from surveys in the solar neighbourhood are lower by about two orders of magnitude than those predicted theoretically, and the mass transfer rates in nova binaries, as estimated from observed luminosities in quiescence, are higher than those allowed by the thermonuclear runaway model for nova outbursts. These discrepancies disappear if mass transfer (at a high rate) takes place for only a few hundred years before and a few hundred years after an eruption, but declines afterwards and remains off for most of the time between outbursts. We show that such a behavior is to be expected if one takes into account the variation of binary separation, due to mass ejection on the one hand and angular momentum losses on the other hand.One of the aspects of this scenario, on which we report in more detail, is the possibility of enhanced Roche-lobe overflow of the secondary, due to its expansion that results from irradiation by the high nova luminosity. We followed the evolution of a 0.5M⊙ main sequence star illuminated by a changing flux, typical of a classical nova. The numerical results indicate that, in spite of the slight binary separation that may occur after eruption, mass loss from the irradiated and thus bloated secondary should continue for a few hundred years. Other aspects of the variable Ṁ scenario are briefly summarized.

scholarly journals Is HR 6819 a triple system containing a black hole?

2020 ◽  
Vol 641 ◽  
pp. A43
Author(s):  
J. Bodensteiner ◽  
T. Shenar ◽  
L. Mahy ◽  
M. Fabry ◽  
P. Marchant ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Black Hole ◽  
Binary System ◽  
Triple System ◽  
Alternative Explanation ◽  
Transfer Event ◽  
Be Star ◽  
Type Giant ◽  
Optical Flux ◽  
Orbital Analysis

Context. HR 6819 was recently proposed to be a triple system consisting of an inner B-type giant plus black hole (BH) binary with an orbital period of 40 d and an outer Be tertiary. This interpretation is mainly based on two inferences: that the emission attributed to the outer Be star is stationary and that the inner star, which is used as mass calibrator for the BH, is a B-type giant. Aims. We re-investigate the properties of HR 6819 to search for a possibly simpler alternative explanation for HR 6819, which does not invoke the presence of a triple system with a BH in the inner binary. Methods. Based on an orbital analysis, the disentangling of the spectra of the two visible components and the atmosphere analysis of the disentangled spectra, we investigate the configuration of the system and the nature of its components. Results. Disentangling implies that the Be component is not a static tertiary, but rather a component of the binary in the 40 d orbit. The inferred radial velocity amplitudes of K1 = 60.4 ± 1.0 km s−1 for the B-type primary and K2 = 4.0 ± 0.8 km s−1 for the Be-type secondary imply an extreme mass ratio of M2/M1 = 15 ± 3. We find that the B-type primary, which we estimate to contribute about 45% to the optical flux, has an effective temperature of Teff = 16 ± 1 kK and a surface gravity of log g = 2.8 ± 0.2 [cgs], while the Be secondary, which contributes about 55% to the optical flux, has Teff = 20 ± 2 kK and log g = 4.0 ± 0.3 [cgs]. We infer spectroscopic masses of 0.4−0.1+0.3and 6−3+5 for the primary and secondary which agree well with the dynamical masses for an inclination of i = 32°. This indicates that the primary might be a stripped star rather than a B-type giant. Evolutionary modelling suggests that a possible progenitor system would be a tight (Pi ≈ 2 d) B+B binary system that experienced conservative mass transfer. While the observed nitrogen enrichment of the primary conforms with the predictions of the evolutionary models, we find no indications for the predicted He enrichment. Conclusions. We suggest that HR 6819 is a binary system consisting of a stripped B-type primary and a rapidly-rotating Be star that formed from a previous mass-transfer event. In the framework of this interpretation, HR 6819 does not contain a BH. Interferometry can distinguish between these two scenarios by providing an independent measurement of the separation between the visible components.

scholarly journals Interpretation of CEMP(s) and CEMP(s + r) Stars with AGB Models

2009 ◽  
Vol 26 (3) ◽  
pp. 314-321 ◽  
Author(s):  
Sara Bisterzo ◽  
Roberto Gallino ◽  
Oscar Straniero ◽  
Wako Aoki
Keyword(s):  
Mass Transfer ◽  
Binary System ◽  
Neutron Capture ◽  
Molecular Cloud ◽  
Main Sequence ◽  
Asymptotic Giant Branch ◽  
Agb Stars ◽  
Spectroscopic Observations ◽  
Theoretical Predictions ◽  
Process Elements

AbstractAsymptotic Giant Branch (AGB) stars play a fundamental role in s-process nucleosynthesis during their thermal pulsing phase. The theoretical predictions obtained by AGB models at different masses, s-process efficiencies, dilution factors and initial r-enrichment, are compared with spectroscopic observations of Carbon-Enhanced Metal-Poor stars enriched in s-process elements, CEMP(s), collected from the literature. We discuss here five stars as example, CS 22880-074, CS 22942-019, CS 29526-110, HE 0202-2204 and LP 625-44. All these objects lie on the main sequence or on the giant phase, clearly before the thermally pulsing AGB stage. The hypothesis of mass transfer from an AGB companion, would explain the observed s-process enhancement. CS 29526-110 and LP 625-44 are CEMP(s + r) objects, and are interpreted assuming that the molecular cloud, from which the binary system formed, was already enriched in r-process elements by SNII pollution. In several cases, the observed s-process distribution may be accounted for by AGB models of different initial masses with proper 13C-pocket efficiencies and dilution factors. Na (and Mg), produced via the neutron capture chain starting from 22Ne, may provide an indicator of the initial AGB mass.

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