scholarly journals Black widow evolution: magnetic braking by an ablated wind

2020 ◽  
Vol 495 (4) ◽  
pp. 3656-3665 ◽  
Author(s):  
Sivan Ginzburg ◽  
Eliot Quataert
Keyword(s):  
Time Scale ◽  
Binary Systems ◽  
Close Binary ◽  
Millisecond Pulsar ◽  
Evaporation Time ◽  
Black Widow ◽  
Dynamical Time ◽  
Magnetic Braking ◽  
Γ Ray ◽  
Pulsar Populations

ABSTRACT Black widows are close binary systems in which a millisecond pulsar is orbited by a companion, a few per cent the mass of the sun. It has been suggested that the pulsar’s rotationally powered γ-ray luminosity gradually evaporates the companion, eventually leaving behind an isolated millisecond pulsar. The evaporation efficiency is determined by the temperature Tch ∝ F2/3 to which the outflow is heated by the flux F on a dynamical time-scale. Evaporation is most efficient for companions that fill their Roche lobes. In this case, the outflow is dominated by a cap around the L1 point with an angle θg ∼ (Tch/Tg)1/2, and the evaporation time is tevap = 0.46(Tch/Tg)−2 Gyr, where Tg > Tch is the companion’s virial temperature. We apply our model to the observed black widow population, which has increased substantially over the last decade, considering each system’s orbital period, companion mass, and pulsar spin-down power. While the original black widow (PSR B1957+20) evaporates its companion on a few Gyr time-scale, direct evaporation on its own is too weak to explain the overall population. We propose instead that the evaporative wind couples to the companion’s magnetic field, removes angular momentum from the binary, and maintains stable Roche lobe overflow. While a stronger wind carries more mass, it also reduces the Alfvén radius, making this indirect magnetic braking mechanism less dependent on the flux $t_{\rm mag}\propto t_{\rm evap}^{1/3}$. This reduces the scatter in evolution times of observed systems, thus better explaining the combined black widow and isolated millisecond pulsar populations.

scholarly journals Effects of dissipating gas drag on planetesimal accretion in binary systems

2007 ◽  
Vol 3 (S249) ◽  
pp. 419-424
Author(s):  
Ji-Wei Xie ◽  
Ji-Lin Zhou
Keyword(s):  
Time Scale ◽  
Binary Systems ◽  
Major Axis ◽  
Close Binary ◽  
Planetary Formation ◽  
Semi Major Axis ◽  
Companion Star ◽  
Close Binary Systems ◽  
Gas Drag ◽  
Better Than

AbstractWe numerically investigate the conditions for planetesimal accretion in the circumprimary disk under the perturbing presence of a companion star, with focus on the γ Cephei system. Gas drag is included with a dissipating time scale of 105years. We show at the beginning(within 103∼ 104years), gas drag damps the ΔVbetween planetesimals of same sizes and increases ΔVbetween planetesimals of different sizes. However, after increasing to high values(300∼800m/s), we find the ΔVbetween bodies of different sizes decrease to very low values (below 10m/s) in a few 105yrs(depending on the gas-dissipating time scaleTdamp, radial sizeRpand semi-major axisapof planetesimals). Hence, the high ΔVis somewhat short-lived, and runaway accretion can be turned on later. We conclude that the conditions for planetary formation in binary systems (even close binary systems) are much better than what we expected before.

scholarly journals Binary evolution leading to the formation of the very massive neutron star in the J0740+6620 binary system

2020 ◽  
Vol 495 (2) ◽  
pp. 2509-2514
Author(s):  
M Echeveste ◽  
M L Novarino ◽  
O G Benvenuto ◽  
M A De Vito
Keyword(s):  
Neutron Star ◽  
Binary System ◽  
Effective Temperature ◽  
Binary Systems ◽  
Close Binary ◽  
Normal Donor ◽  
Millisecond Pulsar ◽  
Massive Neutron Star ◽  
Binary Evolution ◽  
Age Of The Universe

ABSTRACT We study the evolution of close binary systems in order to account for the existence of the recently observed binary system containing the most massive millisecond pulsar ever detected, PSR J0740+6620, and its ultra-cool helium white dwarf companion. In order to find a progenitor for this object we compute the evolution of several binary systems composed by a neutron star and a normal donor star employing our stellar code. We assume conservative mass transfer. We also explore the effects of irradiation feedback on the system. We find that irradiated models also provide adequate models for the millisecond pulsar and its companion, so both irradiated and non irradiated systems are good progenitors for PSR J0740+6620. Finally, we obtain a binary system that evolves and accounts for the observational data of the system composed by PSR J0740+6620 (i.e. orbital period, mass, effective temperature and inferred metallicity of the companion, and mass of the neutron star) in a time scale smaller than the age of the Universe. In order to reach an effective temperature as low as observed, the donor star should have an helium envelope as demanded by observations.

scholarly journals Aspects of the Angular Momentum Loss Problem for Cool Close Binary Systems

1992 ◽  
Vol 151 ◽  
pp. 415-418 ◽  
Author(s):  
E. Budding ◽  
O. B. Slee ◽  
R. T. Stewart
Keyword(s):  
Angular Momentum ◽  
Observational Data ◽  
Coronal Loop ◽  
Binary Systems ◽  
Close Binary ◽  
Dwarf Stars ◽  
Angular Momentum Loss ◽  
Magnetic Braking ◽  
Binary Evolution ◽  
Insight Into

We concentrate on the application of centimeter wavelength observational data to the coronae of rapidly rotating active dwarf stars. In particular we seek insight into coronal loop geometries, and their possible relevance to the magnetic braking mechanism, which must play a key role in binary evolution scenarios for such stars.

scholarly journals X-Ray and Optical Properties of Black Widows and Redbacks

2017 ◽  
Vol 13 (S337) ◽  
pp. 43-46 ◽  
Author(s):  
Mallory S.E. Roberts ◽  
Hind Al Noori ◽  
Rodrigo A. Torres ◽  
Maura A. McLaughlin ◽  
Peter A. Gentile ◽  
...  
Keyword(s):  
Optical Properties ◽  
Binary Systems ◽  
Optical Emission ◽  
Close Binary ◽  
X Rays ◽  
Millisecond Pulsar ◽  
Optical Studies ◽  
Optical Photometry ◽  
X Ray ◽  
Pulsar Wind

AbstractBlack widows and redbacks are binary systems consisting of a millisecond pulsar in a close binary with a companion having matter driven off of its surface by the pulsar wind. X-rays due to an intrabinary shock have been observed from many of these systems, as well as orbital variations in the optical emission from the companion due to heating and tidal distortion. We have been systematically studying these systems in radio, optical and X-rays. Here we will present an overview of X-ray and optical studies of these systems, including new XMM-Newton and NuStar data obtained from several of them, along with new optical photometry.

Some Results of the Spectroscopic Study of Four Close Binary Systems of Early Spectral Types

1965 ◽  
Vol 5 ◽  
pp. 120-130
Author(s):  
T. S. Galkina
Keyword(s):  
Spectroscopic Study ◽  
Spectral Type ◽  
Spectroscopic Investigation ◽  
Binary Systems ◽  
Quantitative Information ◽  
Close Binary ◽  
Physical Parameters ◽  
Absorption And Emission ◽  
Close Binary Systems ◽  
Quantitative Estimates

It is necessary to have quantitative estimates of the intensity of lines (both absorption and emission) to obtain the physical parameters of the atmosphere of components.Some years ago at the Crimean observatory we began the spectroscopic investigation of close binary systems of the early spectral type with components WR, Of, O, B to try and obtain more quantitative information from the study of the spectra of the components.

Quasi-Periodic Oscillations in Dwarf Novae

1979 ◽  
Vol 46 ◽  
pp. 77-88
Author(s):  
Edward L. Robinson
Keyword(s):  
Binary Systems ◽  
Outer Edge ◽  
Light Curves ◽  
Close Binary ◽  
Bright Spot ◽  
Dwarf Novae ◽  
Periodic Oscillations ◽  
High Frequencies ◽  
Short Period ◽  
Typical Time

Three distinct kinds of rapid variations have been detected in the light curves of dwarf novae: rapid flickering, short period coherent oscillations, and quasi-periodic oscillations. The rapid flickering is seen in the light curves of most, if not all, dwarf novae, and is especially apparent during minimum light between eruptions. The flickering has a typical time scale of a few minutes or less and a typical amplitude of about .1 mag. The flickering is completely random and unpredictable; the power spectrum of flickering shows only a slow decrease from low to high frequencies. The observations of U Gem by Warner and Nather (1971) showed conclusively that most of the flickering is produced by variations in the luminosity of the bright spot near the outer edge of the accretion disk around the white dwarf in these close binary systems.

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.

scholarly journals Millisecond Pulsars

1989 ◽  
Vol 8 ◽  
pp. 161-165
Author(s):  
J.H. Krolik
Keyword(s):  
Neutron Star ◽  
Stellar Evolution ◽  
Close Binary ◽  
Millisecond Pulsar ◽  
Millisecond Pulsars ◽  
Physical Conditions ◽  
Cast Doubt ◽  
Standard Picture ◽  
The Universe ◽  
New System

AbstractMillisecond pulsars are intrinsically interesting because they illustrate some of the most extreme physical conditions to be found anywhere in the Universe, and because their evolution exhibits several stages of great drama. It had been widely believed for several years that spin-up of an old neutron star by accretion from a close stellar companion explained their fast rotation, but the absence of companions in several cases cast doubt on that picture. This spring a millisecond pulsar in a close binary was discovered in which the companion appears to be evaporating, thus reconciling the existence of lone millisecond pulsars with the standard picture. Ongoing observations of this new system, and complementary calculations, promise to answer many of the questions remaining about this dramatic phase in stellar evolution.

scholarly journals Solitons in the Close Binary Systems

1998 ◽  
Vol 11 (1) ◽  
pp. 398-398
Author(s):  
Kenji Tanabe
Keyword(s):  
Gravity Waves ◽  
Binary Systems ◽  
Kdv Equation ◽  
Frame Of Reference ◽  
Close Binary ◽  
Flare Activity ◽  
Lagrangian Point ◽  
Nls Equation ◽  
Close Binary Systems ◽  
The Earth

Propagation of the surface waves of the lobe-filing components of close binary systems is investigated theoretically. Such waves are considered to be analogous to the gravity waves of water on the earth. As a result, the equations of the surface wave in the rotating frame of reference are reduced to the so-called Kortewegde Vries (KdV) equation and non-linear Schroedinger (NLS) equation according to its ”depth”. Each of these equations is known to have the solution of soliton. When this soliton is sent to the other component of the binary system through the Lagrangian point, it can give rise to the flare activity observed in some kinds of close binary systems.

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