scholarly journals Diagnosing pulsar winds in black-widow, redback, and other binary millisecond pulsar systems

2019 ◽  
Vol 492 (2) ◽  
pp. 1579-1593
Author(s):  
Anne Zilles ◽  
Kumiko Kotera ◽  
Rene Rohrmann ◽  
Leandro Althaus
Keyword(s):  
Binary Systems ◽  
Particle Energy ◽  
Millisecond Pulsar ◽  
Close Orbit ◽  
Night Side ◽  
Pulsar Wind ◽  
Binary Evolution ◽  
Lower Limits ◽  
Pulsar Winds ◽  
Temperature Asymmetry

ABSTRACT Binary systems composed of a recycled millisecond pulsar and a stellar companion in close orbit could be excellent sites to diagnose pulsar winds. In such systems, the pulsar outflow irradiates and heats up the companion atmosphere, which can lead to the observation of strong day/night modulations in temperature. We demonstrate with particle shower simulations that the particle energy of the wind affects the heating depth in the atmosphere: the wind heat can be deposited above or below the photosphere, leading to different signatures in the observed spectra. We apply our method to four specific systems: We find that systems with cool night-side companions showing strong temperature variations can give interesting lower limits on the particle energy in the winds. In particular, if the companion night side of PSR B1957+20 were to be suddenly irradiated, deep heating would only take place if particles with energy >100 TeV were present. Observational evidence of deep heating in this system thus suggests that (i) such particles exist in the pulsar wind and/or (ii) binary evolution non-trivially takes the companion to the observed temperature asymmetry. Besides, the observed temperature difference can be maintained only with particle energies of the order of 100 MeV.

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 The first binary pulsars and what they told us about binary evolution

2017 ◽  
Vol 13 (S337) ◽  
pp. 37-42
Author(s):  
Dipankar Bhattacharya
Keyword(s):  
Neutron Stars ◽  
Early Development ◽  
Binary Systems ◽  
Historical Review ◽  
Binary Pulsars ◽  
Low Mass ◽  
Pulsar Wind ◽  
Binary Evolution ◽  
The Impact

AbstractThe first few binary pulsars revealed the richness of evolution possible in binary systems containing neutron stars. Products of different evolutionary routes, in high and low mass binaries, as well as examples of evolution affected by the pulsar wind were among the first ten objects discovered. This article presents a historical review of the impact of binary pulsars on the early development of ideas regarding the evolution of neutron stars in binary systems.

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.

scholarly journals The H.E.S.S. Galactic Plane Survey

2009 ◽  
Vol 5 (H15) ◽  
pp. 808-808
Author(s):  
Emma de Oña-Wilhelmi
Keyword(s):  
Supernova Remnants ◽  
Binary Systems ◽  
Galactic Plane ◽  
Giant Molecular Clouds ◽  
Pulsar Wind Nebulae ◽  
Compact Binary ◽  
Pulsar Wind ◽  
Star Formation Regions ◽  
Galactic Sources ◽  
Gps Observations

AbstractThe H.E.S.S. Galactic Plane Survey (GPS) has revealed a large number of Galactic Sources, including Pulsar Wind Nebulae (PWN), Supernova Remnants (SNRs), giant molecular clouds, star formation regions and compact binary systems, as well as a number of unidentified objects, or dark sources, for which no obvious counterparts at other wavelengths have yet been found. We will review the latest results from the GPS observations and discuss the most interesting cases.

scholarly journals Infrared nebulae around bright massive stars as indicators for binary interactions

2018 ◽  
Vol 618 ◽  
pp. A110 ◽  
Author(s):  
J. Bodensteiner ◽  
D. Baade ◽  
J. Greiner ◽  
N. Langer
Keyword(s):  
Supernova Remnants ◽  
Binary Systems ◽  
Massive Stars ◽  
Space Velocity ◽  
Be Stars ◽  
Global Risk ◽  
Wide Range ◽  
Bow Shocks ◽  
Binary Evolution ◽  
Stellar Properties

Context. Recent studies show that more than 70% of massive stars do not evolve as effectively single stars, but as members of interacting binary systems. The evolution of these stars is thus strongly altered compared to similar but isolated objects. Aims. We investigate the occurrence of parsec-scale mid-infrared nebulae around early-type stars. If they exist over a wide range of stellar properties, one possible overarching explanation is non-conservative mass transfer in binary interactions, or stellar mergers. Methods. For ∼3850 stars (all OBA stars in the Bright Star Catalogue (BSC), Be stars, BeXRBs, and Be+sdO systems), we visually inspect WISE 22 μm images. Based on nebular shape and relative position, we distinguish five categories: offset bow shocks structurally aligned with the stellar space velocity, unaligned offset bow shocks, and centered, unresolved, and not classified nebulae. Results. In the BSC, we find that 28%, 13%, and 0.4% of all O, B, and A stars, respectively, possess associated infrared (IR) nebulae. Additionally, 34/234 Be stars, 4/72 BeXRBs, and 3/17 Be+sdO systems are associated with IR nebulae. Conclusions. Aligned or unaligned bow shocks result from high relative velocities between star and interstellar medium (ISM) that are dominated by the star or the ISM, respectively. About 13% of the centered nebulae could be bow shocks seen head- or tail-on. For the rest, the data disfavor explanations as remains of parental disks, supernova remnants of a previous companion, and dust production in stellar winds. The existence of centered nebulae also at high Galactic latitudes strongly limits the global risk of coincidental alignments with condensations in the ISM. Mass loss during binary evolution seems a viable mechanism for the formation of at least some of these nebulae. In total, about 29% of the IR nebulae (2% of all OBA stars in the BSC) may find their explanation in the context of binary evolution.

Formation of the SMC WO+O binary AB8

2018 ◽  
Vol 14 (S346) ◽  
pp. 78-82
Author(s):  
Chen Wang ◽  
Norbert Langer ◽  
Götz Gräfener ◽  
Pablo Marchant
Keyword(s):  
Binary Systems ◽  
Mass Loss Rate ◽  
Vital Role ◽  
Least Square ◽  
High Mass ◽  
Stellar Winds ◽  
High Mass Loss ◽  
Low Metallicity ◽  
Binary Evolution ◽  
Oxygen Ratio

AbstractWolf-Rayet (WR) stars are stripped stellar cores that form through strong stellar wind or binary mass transfer. It is proposed that binary evolution plays a vital role in the formation of WR stars in low metallicity environments due to the metallicity dependance of stellar winds. However observations indicate a similar binary fraction of WR stars in the Small Magellanic Cloud (SMC) compared to the Milky Way. There are twelve WR stars in the SMC and five of them are members of binary systems. One of them (SMC AB8) harbors a WO type star. In this work we explore possible formation channels of this binary. We use the MESA code to compute large grids of binary evolution models, and then use least square fitting to compare our models with the observations. In order to reproduce the key properties of SMC AB8, we require efficient semiconvection to produce a sufficiently large convective core, as well as a longer He-burning lifetime. We also need a high mass loss rate during the WN stage to assist the removal of the outer envelope. In this way, we can reproduce the observed properties of AB8, except for the surface carbon to oxygen ratio, which requires further investigation.

scholarly journals The influence of stellar wind mass loss on the evolution of massive close binaries.

1979 ◽  
Vol 83 ◽  
pp. 409-414
Author(s):  
D. Vanbeveren ◽  
J.P. De Grève ◽  
C. de Loore ◽  
E.L. van Dessel
Keyword(s):  
Mass Loss ◽  
Stellar Wind ◽  
Binary Systems ◽  
Mass Loss Rate ◽  
Radiation Force ◽  
Roche Lobe ◽  
Close Binaries ◽  
Massive Binary Systems ◽  
Binary Evolution ◽  
X Ray Binaries

It is generally accepted that massive (and thus luminous) stars lose mass by stellar wind, driven by radiation force (Lucy and Solomon, 1970; Castor et al. 1975). For the components of massive binary systems, rotational and gravitational effects may act together with the radiation force so as to increase the mass loss rate. Our intention here is to discuss the influence of a stellar wind mass loss on the evolution of massive close binaries. During the Roche lobe overflow phase, mass and angular momentum can leave the system. Possible reasons for mass loss from the system are for example the expansion of the companion due to accretion of the material lost by the mass losing star (Kippenhahn and Meyer-Hofmeister, 1977) or the fact that due to the influence of the radiation force in luminous stars, mass will be lost over the whole surface of the star and not any longer through a possible Lagrangian point as in the case of classical Roche lobe overflow (Vanbeveren, 1978). We have therefore investigated the influence of both processes on binary evolution. Our results are applied to 5 massive X-ray binaries with a possible implication for the existence of massive Wolf Rayet stars with a very close invisible compact companion. A more extended version of this talk is published in Astronomy and Astrophysics (Vanbeveren et al. 1978; Vanbeveren and De Grève, 1978). Their results will be briefly reviewed.

scholarly journals Observational properties of massive black hole binary progenitors

2018 ◽  
Vol 609 ◽  
pp. A94 ◽  
Author(s):  
R. Hainich ◽  
L. M. Oskinova ◽  
T. Shenar ◽  
P. Marchant ◽  
J. J. Eldridge ◽  
...  
Keyword(s):  
Mass Loss ◽  
Binary Systems ◽  
Spectral Characteristics ◽  
Broad Band ◽  
Stellar Atmosphere ◽  
High Mass ◽  
Massive Black Hole ◽  
Synthetic Spectra ◽  
Binary Evolution ◽  
Loss Rates

Context. The first directly detected gravitational waves (GW 150914) were emitted by two coalescing black holes (BHs) with masses of ≈ 36 M⊙ and ≈ 29 M⊙. Several scenarios have been proposed to put this detection into an astrophysical context. The evolution of an isolated massive binary system is among commonly considered models. Aims. Various groups have performed detailed binary-evolution calculations that lead to BH merger events. However, the question remains open as to whether binary systems with the predicted properties really exist. The aim of this paper is to help observers to close this gap by providing spectral characteristics of massive binary BH progenitors during a phase where at least one of the companions is still non-degenerate. Methods. Stellar evolution models predict fundamental stellar parameters. Using these as input for our stellar atmosphere code (Potsdam Wolf-Rayet), we compute a set of models for selected evolutionary stages of massive merging BH progenitors at different metallicities. Results. The synthetic spectra obtained from our atmosphere calculations reveal that progenitors of massive BH merger events start their lives as O2-3V stars that evolve to early-type blue supergiants before they undergo core-collapse during the Wolf-Rayet phase. When the primary has collapsed, the remaining system will appear as a wind-fed high-mass X-ray binary. Based on our atmosphere models, we provide feedback parameters, broad band magnitudes, and spectral templates that should help to identify such binaries in the future. Conclusions. While the predicted parameter space for massive BH binary progenitors is partly realized in nature, none of the known massive binaries match our synthetic spectra of massive BH binary progenitors exactly. Comparisons of empirically determined mass-loss rates with those assumed by evolution calculations reveal significant differences. The consideration of the empirical mass-loss rates in evolution calculations will possibly entail a shift of the maximum in the predicted binary-BH merger rate to higher metallicities, that is, more candidates should be expected in our cosmic neighborhood than previously assumed.

scholarly journals A model for redistributing heat over the surface of irradiated spider companions

2020 ◽  
Vol 499 (2) ◽  
pp. 1758-1768 ◽  
Author(s):  
Guillaume Voisin ◽  
M R Kennedy ◽  
R P Breton ◽  
C J Clark ◽  
D Mata-Sánchez
Keyword(s):  
Binary Systems ◽  
Computational Cost ◽  
Effective Equation ◽  
Stellar Envelope ◽  
Direct Heating ◽  
Systematic Effects ◽  
Low Mass ◽  
Pulsar Wind ◽  
Heating Model ◽  
Future Work

ABSTRACT Spider pulsars are binary systems containing an energetic millisecond pulsar that intensely irradiates a closely orbiting low-mass companion. Modelling their companion’s optical light curves is essential to the study of the orbital properties of the binary, including the determination of the pulsar mass, characterizing the pulsar wind, and the star itself. We aim to generalize the traditional direct heating model of irradiation, whereby energy deposited by the pulsar wind into the stellar envelope is locally re-emitted, by introducing heat redistribution via diffusion and convection within the outer stellar envelope. We approximate the irradiated stellar envelope as a 2D shell. This allows us to propose an effective equation of energy conservation that can be solved at a reduced computational cost. We then implement this model in the icarus software and use evidence sampling to determine the most likely convection and diffusion laws for the light curve of the redback companion of PSR J2215+5135. Redistribution effects concentrate near the terminator line of pulsar irradiation, and can create apparent hot and cold spots. Among the models tested for PSR J2215+5135, we find that all models with heat redistribution are more likely than symmetric direct heating. The best-fitting redistribution model involves diffusion together with a uniformly rotating envelope. However, we caution that all models still present serious systematic effects, and that prior knowledge from pulsar timing, spectroscopy, and distance are key to determine with certainty the most accurate redistribution law. We propose an extension of the direct heating framework that allows for exploring a variety of heat redistribution effects. Future work is necessary to determine the relevant laws from first principles and empirically using complementary observations.

scholarly journals Theory of Pulsar Winds

2004 ◽  
Vol 218 ◽  
pp. 143-150
Author(s):  
A. Melatos
Keyword(s):  
Linear Accelerator ◽  
Recent Progress ◽  
Near Infrared ◽  
Poynting Flux ◽  
Open Questions ◽  
Field Geometry ◽  
Parametric Instabilities ◽  
Pulsar Wind ◽  
Pulsar Winds ◽  
The Magnetic Field

Recent progress in the theory of pulsar wind electrodynamics is reviewed, with emphasis on the following open questions, (i) Is the bipolar, jet-torus geometry imprinted by collimation or injection? (ii) what is the magnetic field geometry as a function of latitude, and is it stable? (iii) How rapidly does the postshock flow fluctuate, e.g. in the near infrared? (iv) The σ paradox: is Poynting flux converted gradually to kinetic energy flux as the wind expands, as in a linear accelerator, or is the conversion lossy, due to reconnection or parametric instabilities in a wave-like outflow?

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