scholarly journals Discless Accretion in Intermediate Polars?

1997 ◽  
Vol 163 ◽  
pp. 420-423
Author(s):  
David A.H. Buckley
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
X Ray ◽  
Spin Period ◽  
Synodic Period ◽  
Intermediate Polars

AbstractI review the evidence for disc and discless accretion in the asynchronous magnetic CVs, the intermediate polars (IPs). The presence and relative amplitudes of the spin and synodic (beat) X-ray periods, and related orbital sidebands, are very model dependent, and support disc accretion dominating in all the well-studied IPs. A component of non-disc accretion is sometimes observed, a result of stream overflow penetrating to the magnetosphere, and is responsible for the synodic period. The recently discovered polarized IP, RX J1712.6–2414, is a prime candidate (the first) for purely discless, stream-fed accretion in such a system. While the polarisation varies at the spin period, the X-ray variations occur at the synodic period, a result of the modulation in the mass transfer rate for a discless accretor.

scholarly journals Super-Eddington Accretion in the Formation of Low-Mass X-ray Binaries and Millisecond Pulsars

1997 ◽  
Vol 163 ◽  
pp. 828-829 ◽  
Author(s):  
R. F. Webbink ◽  
V. Kalogera
Keyword(s):  
Mass Transfer ◽  
Initial Phase ◽  
Transfer Rate ◽  
Birth Rate ◽  
Mass Transfer Rate ◽  
Millisecond Pulsars ◽  
X Ray ◽  
Low Mass ◽  
Orbital Periods ◽  
X Ray Binaries

AbstractConsiderations of donor star stability, age, and mass transfer rate show that low-mass X-ray binaries and binary millisecond pulsars with orbital periods longer than a few days must have survived an initial phase of super-Eddington mass transfer. We review the physical arguments leading to this conclusion, and examine its implications for the apparent discrepancy between the death rate for low-mass X-ray binaries and the birth rate of binary millisecond pulsars.

scholarly journals Irregular X-ray Variation of LMC X-3

1995 ◽  
Vol 151 ◽  
pp. 336-337
Author(s):  
H.C. Pan ◽  
G.K. Skinner ◽  
R.A. Sunyaev ◽  
N.L. Alexandrovich
Keyword(s):  
Mass Transfer ◽  
Energy Range ◽  
Spectral Resolution ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Space Station ◽  
Large Magellanic Cloud ◽  
Accretion Disc ◽  
X Ray ◽  
Coded Mask

LMC X-3 is an X-ray binary in the Large Magellanic Cloud. It was discovered by UHURU and observations with various satellites showed that the X-ray source was variable by a factor of up to 100 (e.g. Traves et al. 1988). Using the GINGA and HEAO-1 observations, Cowley et al. (1991) found a strong ∼ 198 (or possibly ∼ 99) day modulation in the X-ray luminosities of LMC X-3. They suggested that this modulation may be due to an accretion disc precession, or periodic variations in the mass transfer rate, or a combination of both.We observed LMC X-3 with the TTM in 1988-1990. The present paper gives some results from the analysis of the data obtained.The TTM is a coded mask telescope on board the MIR space station. It is capable of producing images in the energy range 2-30 keV with a spectral resolution of about 18% at 6 keV (Brinkman et al. 1985).

scholarly journals VY Sculptoris stars are Magnetic Cataclysmic Variables

2004 ◽  
Vol 190 ◽  
pp. 46-52 ◽  
Author(s):  
Jean-Pierre Lasota ◽  
Jean-Marie Hameury
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Magnetic Moments ◽  
Mass Transfer Rate ◽  
Cataclysmic Variables ◽  
Accretion Disc ◽  
Intermediate States ◽  
Intermediate Polars ◽  
Magnetic Cataclysmic Variables ◽  
Evolutionary Aspects

AbstractWe show that VY Scl stars must be magnetized in order to account for the absence of outbursts during their low and intermediate states. Absence of outbursts during low states requires only rather low magnetic moments but in systems in which the drops and rises of luminosity are slower than it takes for the accretion disc to adjust viscously to the variation in mass-transfer rate preventing outbursts require magnetic moments of Intermediate Polars. We discuss some evolutionary aspects of this conclusion.

scholarly journals Updated orbital ephemeris of the ADC source X 1822-371: a stable orbital expansion over 40 years

2019 ◽  
Vol 625 ◽  
pp. L12 ◽  
Author(s):  
S. M. Mazzola ◽  
R. Iaria ◽  
T. Di Salvo ◽  
A. F. Gambino ◽  
A. Marino ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Orbital Period ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Optical Data ◽  
Quadratic Model ◽  
Arrival Times ◽  
Companion Star ◽  
X Ray ◽  
Period Derivative

Aims. Source X 1822-371 is an eclipsing compact binary system with a period close to 5.57 h and an orbital period derivative Ṗorb of 1.51(7)×10−10 s s−1. The very high value of Ṗorb is compatible with a super-Eddington mass transfer rate from the companion star, as suggested by X-ray and optical data. The XMM-Newton observation taken in 2017 allows us to update the orbital ephemeris and verify whether the orbital period derivative has been stable over the past 40 yr. Methods. We added two new values obtained from the Rossi-XTE (RXTE) and XMM-Newton observations performed in 2011 and 2017, respectively, to the X-ray eclipse arrival times from 1977 to 2008. We estimated the number of orbital cycles and the delays of our eclipse arrival times spanning 40 yr, using as reference time the eclipse arrival time obtained from the RXTE observation taken in 1996. Results. Fitting the delays with a quadratic model, we found an orbital period Porb = 5.57062957(20) h and a Ṗorb value of 1.475(54)×10−10 s s−1. The addition of a cubic term to the model does not significantly improve the fit quality. We also determined a spin-period value of Pspin = 0.5915669(4) s and its first derivative Ṗspin = − 2.595(11) × 10−12 s s−1. Conclusions. Our results confirm the scenario of a super-Eddington mass transfer rate; we also exclude a gravitational coupling between the orbit and the change in the oblateness of the companion star triggered by the nuclear luminosity of the companion star.

scholarly journals V1082-Sgr: A magnetic cataclysmic variable with a lobe-filling companion star

2019 ◽  
Vol 489 (3) ◽  
pp. 3031-3035
Author(s):  
Xiaojie Xu ◽  
Yong Shao ◽  
Xiang-Dong Li
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Flux Ratio ◽  
Roche Lobe ◽  
High Mass ◽  
Cataclysmic Variable ◽  
X Ray ◽  
V Band ◽  
Sgr A

ABSTRACT V1082 Sgr is a cataclysmic variable with accretion luminosity above 1034 erg s−1, indicating a mass-transfer rate above $10^{-9}\, \mathrm{M}_{\odot }$  yr−1. However, its K-type companion was suggested to be underfilling its Roche lobe (RL), making the high mass-transfer rate a mystery. In this work we propose a possible model to explain this discrepancy. The system is proposed to be an intermediate polar, with its K-type companion filling its RL. The mass of the white dwarf star is evaluated to be $0.77\pm 0.11\, \mathrm{M}_{\odot }$ from both X-ray continuum fitting and Fe line flux ratio measurements. We make numerical simulations to search for the possible progenitors of the system. The results show that a binary with an initial 1.5–2.5$\, \mathrm{M}_{\odot }$ companion in a one to two day orbit (or an initial 1.0–1.4$\, \mathrm{M}_{\odot }$ companion in a 3.2–4.1 d orbit) may naturally evolve to a cataclysmic variable with a $\sim 0.55 \pm 0.11\, \mathrm{M}_{\odot }$, Roche-lobe-filling companion in a 0.86 d orbit. The effective temperature of the donor star, the mass-transfer rate, and the derived V-band magnitude are all consistent with previous observations.

scholarly journals On the Influence of Magnetic Field on Accretion Processes in CVs

2015 ◽  
Vol 2 (1) ◽  
pp. 60-65
Author(s):  
D. V. Bisikalo ◽  
A. G. Zhilkin
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
White Dwarf ◽  
Transfer Rate ◽  
Accretion Rate ◽  
Mass Transfer Rate ◽  
Rotation Velocity ◽  
Spin Rotation ◽  
Mhd Simulations ◽  
Intermediate Polars

We consider the influence of such parameters as the value of the proper magnetic field Ba and the spin-rotation velocity of the white dwarf on accretion processes in CVs. The results of 3D MHD simulations have shown that the accretion rate is a non-monotonic function of Ba: with growing Ba it raises in the intermediate polars and decreases in the polars. The maximal accretion rate occurs in the systems, transiting from the stage of intermediate polars to polars; it’s value reaches 60% of the initially set mass transfer rate. We have also shown that the acretion rate decreases with the growing<br />spin-rotation velocity of the white dwarf.

scholarly journals The X-ray binary GX 339–4/V821 Ara: the distance, inclination, evolutionary status, and mass transfer

2019 ◽  
Vol 488 (1) ◽  
pp. 1026-1034 ◽  
Author(s):  
Andrzej A Zdziarski ◽  
Janusz Ziółkowski ◽  
Joanna Mikołajewska
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Accretion Rate ◽  
Mass Transfer Rate ◽  
Compact Object ◽  
Evolutionary Status ◽  
X Rays ◽  
X Ray ◽  
Average Mass

ABSTRACT We consider constraints on the distance, inclination, and component masses in the X-ray binary GX 339–4 resulting from published works, and then construct detailed evolutionary models for the donor. From both considerations, and assuming the black hole nature for the compact object (i.e. its mass ${\gt} 3\, \rm {M}_{\odot }$), the possible donor mass is ≈0.5–$1.4\, \rm {M}_{\odot }$, the inclination is ≈40°–60°, and the distance is ≈8–12 kpc. The corresponding mass of the compact object is ≈4–$11\, \rm {M}_{\odot }$. We then confirm a previous estimate that the theoretical conservative mass transfer rate in GX 339–4 is ${\lesssim} {10^{-9}}\, {\rm M}_{{\odot} }$ yr−1. This is ≳10 times lower than the average mass accretion rate estimated from the long-term X-ray light curve. We show that this discrepancy can be solved in two ways. One solution invokes irradiation of the donor by X-rays from accretion, which can temporarily enhance the mass transfer rate. We found that absorption of a ∼1 per cent of the irradiating luminosity results in the transfer rate equal to the accretion rate. The time-scale at which the transfer rate will vary is estimated to be ∼10 yr, which appears consistent with the observations. The other solution invokes non-conservative mass transfer. This requires that ≈70 per cent of the transferred mass escapes as a strong outflow and carries away the specific angular momentum comparable to that of the donor.

Free Convective Mass Transfer at Isosceles Triangular Surfaces of Varying Inclination

2003 ◽  
Vol 68 (11) ◽  
pp. 2080-2092 ◽  
Author(s):  
Martin Keppert ◽  
Josef Krýsa ◽  
Anthony A. Wragg
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Mass Transfer Process ◽  
Sulfate Solution ◽  
Convective Mass Transfer ◽  
Varying Length ◽  
Inclined Surface ◽  
Vertical Case ◽  
Limiting Diffusion Current

The limiting diffusion current technique was used for investigation of free convective mass transfer at down-pointing up-facing isosceles triangular surfaces of varying length and inclination. As the mass transfer process, copper deposition from acidified copper(II) sulfate solution was used. It was found that the mass transfer rate increases with inclination from the vertical to the horizontal position and decreases with length of inclined surface. Correlation equations for 7 angles from 0 to 90° were found. The exponent in the ShL-RaL correlation ranged from 0.247 for the vertical case, indicating laminar flow, to 0.32 for inclinations of 60 to 90°, indicating mixed or turbulent flow. The general correlation ShL = 0.358(RaL sin θ)0.30 for the RaL sin θ range from 7 × 106 to 2 × 1011 and inclination range from 15 to 90° was obtained.

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