Mass Loss and Stellar Wind in Massive X-Ray Binaries

A number of massive stars of early type is found in X-ray binary systems. The catalog of Bradt et al. (1979) contains 21 sources optically identified with massive stars ranging in spectral type from 06 to B5 out of which 13 are (nearly) unevolved stars and 8 are supergiants. Single stars of this type generally show moderate to strong stellar winds. The X-rays in these binaries originate from accretion onto a compact companion (we restrict the discussion to this type of X-rays).We consider the compact star as a probe traveling through the stellar wind. This probe enables us to derive useful information about the mass outflow of massive stars.After presenting the basic data we derive an upper limit to mass loss rates of unevolved early type stars by studying X-ray pulsars. Next we consider theoretical predictions concerning the influence of X-rays on the stellar wind and compare these with the observations. Finally, using new data from IUE, we draw some conclusions about mass loss rates and velocity laws as derived from X-ray binaries.

What Do We Really Know About the Winds of Massive Stars?

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308020371 ◽

2007 ◽

Vol 3 (S250) ◽

pp. 89-96

Author(s):

D. John Hillier

Keyword(s):

Mass Loss ◽

Massive Stars ◽

Standard Theory ◽

Stellar Winds ◽

X Rays ◽

X Ray ◽

Stellar Photosphere ◽

Weak Winds ◽

Ionization Balance ◽

AbstractThe standard theory of radiation driven winds has provided a useful framework to understand stellar winds arising from massive stars (O stars, Wolf-Rayet stars, and luminous blue variables). However, with new diagnostics, and advances in spectral modeling, deficiencies in our understanding of stellar winds have been thrust to the forefront of our research efforts. Spectroscopic observations and analyses have shown the importance of inhomogeneities in stellar winds, and revealed that there are fundamental discrepancies between predicted and theoretical mass-loss rates. For late O stars, spectroscopic analyses derive mass-loss rates significantly lower than predicted. For all O stars, observed X-ray fluxes are difficult to reproduce using standard shock theory, while observed X-ray profiles indicate lower mass-loss rates, the potential importance of porosity effects, and an origin surprisingly close to the stellar photosphere. In O stars with weak winds, X-rays play a crucial role in determining the ionization balance, and must be taken into account.

Massive star mass-loss revealed by X-ray observations of young supernovae

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318008438 ◽

2018 ◽

Vol 14 (S346) ◽

pp. 83-87

Author(s):

Vikram V. Dwarkadas

Keyword(s):

Mass Loss ◽

Massive Stars ◽

Ambient Medium ◽

Mass Loss Rate ◽

Stellar Mass ◽

X Rays ◽

X Ray ◽

The Common ◽

Almost All ◽

AbstractMassive stars lose a considerable amount of mass during their lifetime. When the star explodes as a supernova (SN), the resulting shock wave expands in the medium created by the stellar mass-loss. Thermal X-ray emission from the SN depends on the square of the density of the ambient medium, which in turn depends on the mass-loss rate (and velocity) of the progenitor wind. The emission can therefore be used to probe the stellar mass-loss in the decades or centuries before the star’s death.We have aggregated together data available in the literature, or analysed by us, to compute the X-ray lightcurves of almost all young supernovae detectable in X-rays. We use this database to explore the mass-loss rates of massive stars that collapse to form supernovae. Mass-loss rates are lowest for the common Type IIP supernovae, but increase by several orders of magnitude for the highest luminosity X-ray SNe.

X-ray diagnostics of massive star winds

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317002952 ◽

2016 ◽

Vol 12 (S329) ◽

pp. 151-155

Author(s):

L. M. Oskinova ◽

R. Ignace ◽

D. P. Huenemoerder

Keyword(s):

High Resolution ◽

Stellar Wind ◽

Massive Star ◽

Massive Stars ◽

Stellar Winds ◽

X Rays ◽

Early Type ◽

Stellar Rotation ◽

X Ray ◽

Early Type Stars

AbstractObservations with powerful X-ray telescopes, such as XMM-Newton and Chandra, significantly advance our understanding of massive stars. Nearly all early-type stars are X-ray sources. Studies of their X-ray emission provide important diagnostics of stellar winds. High-resolution X-ray spectra of O-type stars are well explained when stellar wind clumping is taking into account, providing further support to a modern picture of stellar winds as non-stationary, inhomogeneous outflows. X-ray variability is detected from such winds, on time scales likely associated with stellar rotation. High-resolution X-ray spectroscopy indicates that the winds of late O-type stars are predominantly in a hot phase. Consequently, X-rays provide the best observational window to study these winds. X-ray spectroscopy of evolved, Wolf-Rayet type, stars allows to probe their powerful metal enhanced winds, while the mechanisms responsible for the X-ray emission of these stars are not yet understood.

Be Components in X-Ray Binaries

10.1017/s007418090003802x ◽

1982 ◽

Vol 98 ◽

pp. 347-351 ◽

Cited By ~ 1

Author(s):

C. de Loore ◽

M. Burger ◽

E.L. van Dessel ◽

M. Mouchet

Keyword(s):

Mass Loss ◽

Optical Spectra ◽

X Rays ◽

X Ray ◽

Transient Sources ◽

X Ray Binaries ◽

Periodic Changes ◽

The Be X-ray binaries show rather weak and variable X-rays. They can be divided into two types, the transient sources and the permanent sources. Two ranges for the X-ray luminosity Lx can be discerned: a) Lx~1034erg s−1 (X Per, λ Cas, 2S0114+65, all permanent sources); b) Lx~1036erg s−1. They have long periods, hence wide orbits, they ar not eclipsing and their mass loss rates are low. The optical spectra are generally very variable and irregular, masking periodic changes. No optical orbits exist and only for 4U0115+63 an X-ray orbit is known (Rappaport et al.1978). An overview of the Be X-ray binaries with some of their characteristics is given in Table 1.

Stellar winds in high-mass X-ray binaries

10.1017/s0074180900202131 ◽

1995 ◽

Vol 163 ◽

pp. 271-279

Author(s):

Lex Kaper

Keyword(s):

Stellar Wind ◽

Large Scale ◽

Binary Systems ◽

Compact Object ◽

High Mass ◽

X Rays ◽

Ionization Zone ◽

X Ray ◽

Massive Binary Systems ◽

High-mass X-ray binaries (HMXBs) represent an important stage in the evolution of massive binary systems. The compact object (in most cases an X-ray pulsar) not only provides information on the orbital and stellar parameters, but also probes the stellar wind of the massive companion, an OB supergiant or Be star. The X-ray luminosity directly depends on the density and the velocity of the wind at the orbit of the X-ray source. Important constraints on the stellar-wind structure can be set by studying the orbital modulation of UV P-Cygni profiles. In this paper different aspects of the interactive wind-accretion process are highlighted, such as the highly variable X-ray luminosity, the influence of the X-rays on the radiative acceleration of the wind inside the ionization zone, and the large-scale structures that trail the X-ray source in its orbit.

Wind inhibition by X-ray irradiation in high-mass X-ray binaries

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317002381 ◽

2016 ◽

Vol 12 (S329) ◽

pp. 417-417

Author(s):

Jiří Krtička ◽

Jiří Kubát ◽

Iva Krtičková

Keyword(s):

Optical Depth ◽

Stellar Wind ◽

Light Absorption ◽

Massive Stars ◽

High Mass ◽

X Rays ◽

Radiative Force ◽

X Ray ◽

Theoretical Predictions ◽

AbstractWinds of hot massive stars are driven radiatively by light absorption in the lines of heavier elements. Therefore, the radiative force depends on the wind ionization. That is the reason why the accretion powered X-ray emission of high-mass X-ray binaries influences the radiative force and may even lead to wind inhibition. We model the effect of X-ray irradiation on the stellar wind in high-mass X-ray binaries. The influence of X-rays is given by the X-ray luminosity, by the optical depth between a given point and the X-ray source, and by the distance to the X-ray source. The influence of X-rays is stronger for higher X-ray luminosities and in closer proximity of the X-ray source. There is a forbidden area in the diagrams of X-ray luminosity vs. the optical depth parameter. The observations agree with theoretical predictions, because all wind-powered high-mass X-ray binary primaries lie outside the forbidden area. The positions of real binaries in the diagram indicate that their X-ray luminosities are self-regulated.

Wind inhibition by X-ray irradiation in HMXBs: the influence of clumping and the final X-ray luminosity

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833419 ◽

2018 ◽

Vol 620 ◽

pp. A150 ◽

Cited By ~ 7

Author(s):

J. Krtička ◽

J. Kubát ◽

I. Krtičková

Keyword(s):

Mass Loss ◽

Stellar Wind ◽

Loss Rate ◽

Mass Loss Rate ◽

Terminal Velocity ◽

High Mass ◽

Small Scale ◽

X Rays ◽

X Ray ◽

Context. In wind-powered X-ray binaries, the radiatively driven stellar wind from the primary may be inhibited by the X-ray irradiation. This creates the feedback that limits the X-ray luminosity of the compact secondary. Wind inhibition might be weakened by the effect of small-scale wind inhomogeneities (clumping) possibly affecting the limiting X-ray luminosity. Aims. We study the influence of X-ray irradiation on the stellar wind for different radial distributions of clumping. Methods. We calculate hot star wind models with external irradiation and clumping using our global wind code. The models are calculated for different parameters of the binary. We determine the parameters for which the X-ray wind ionization is so strong that it leads to a decrease of the radiative force. This causes a decrease of the wind velocity and even of the mass-loss rate in the case of extreme X-ray irradiation. Results. Clumping weakens the effect of X-ray irradiation because it favours recombination and leads to an increase of the wind mass-loss rate. The best match between the models and observed properties of high-mass X-ray binaries (HMXBs) is derived with radially variable clumping. We describe the influence of X-ray irradiation on the terminal velocity and on the mass-loss rate in a parametric way. The X-ray luminosities predicted within the Bondi-Hoyle-Lyttleton theory agree nicely with observations when accounting for X-ray irradiation. Conclusions. The ionizing feedback regulates the accretion onto the compact companion resulting in a relatively stable X-ray source. The wind-powered accretion model can account for large luminosities in HMXBs only when introducing the ionizing feedback. There are two possible states following from the dependence of X-ray luminosity on the wind terminal velocity and mass-loss rate. One state has low X-ray luminosity and a nearly undisturbed wind, and the second state has high X-ray luminosity and exhibits a strong influence of X-rays on the flow.

Chemical Abundances of Early Type Stars

10.1017/s007418090011486x ◽

1998 ◽

Vol 188 ◽

pp. 224-225

Author(s):

S. Tanaka ◽

S. Kitamoto ◽

T. Suzuki ◽

K. Torii ◽

M.F. Corcoran ◽

...

Keyword(s):

Surface Layer ◽

Stellar Wind ◽

Nuclear Reactions ◽

X Rays ◽

Early Type ◽

Chemical Abundances ◽

X Ray ◽

Low Metallicity ◽

Early Type Stars

X-rays from early-type stars are emitted by the corona or the stellar wind. The materials in the surface layer of early-type stars are not contaminated by nuclear reactions in the stellar inside. Therefore, abundance study of the early-type stars provides us an information of the abundances of the original gas. However, the X-ray observations indicate low-metallicity, which is about 0.3 times of cosmic abundances. This fact raises the problem on the cosmic abundances.

Radiation-hydrodynamical models of X-ray photoevaporation in carbon-depleted circumstellar discs

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2939 ◽

2019 ◽

Vol 490 (4) ◽

pp. 5596-5614 ◽

Cited By ~ 2

Author(s):

Lisa Wölfer ◽

Giovanni Picogna ◽

Barbara Ercolano ◽

Ewine F van Dishoeck

Keyword(s):

Mass Loss ◽

Gas Phase ◽

Central Star ◽

X Rays ◽

Hydrodynamical Models ◽

X Ray ◽

Energetic Radiation ◽

Low Metallicity ◽

Penetration Depths ◽

ABSTRACT The so-called transition discs provide an important tool to probe various mechanisms that might influence the evolution of protoplanetary discs and therefore the formation of planetary systems. One of these mechanisms is photoevaporation due to energetic radiation from the central star, which can in principal explain the occurrence of discs with inner cavities like transition discs. Current models, however, fail to reproduce a subset of the observed transition discs, namely objects with large measured cavities and vigorous accretion. For these objects the presence of (multiple) giant planets is often invoked to explain the observations. In our work, we explore the possibility of X-ray photoevaporation operating in discs with different gas-phase depletion of carbon and show that the influence of photoevaporation can be extended in such low-metallicity discs. As carbon is one of the main contributors to the X-ray opacity, its depletion leads to larger penetration depths of X-rays in the disc and results in higher gas temperatures and stronger photoevaporative winds. We present radiation-hydrodynamical models of discs irradiated by internal X-ray + EUV radiation assuming carbon gas-phase depletions by factors of three, 10, and 100 and derive realistic mass-loss rates and profiles. Our analysis yields robust temperature prescriptions as well as photoevaporative mass-loss rates and profiles which may be able to explain a larger fraction of the observed diversity of transition discs.

The Formation of Compact Objects in Binary Systems

10.1017/s0074180900073848 ◽

1981 ◽

Vol 93 ◽

pp. 155-175 ◽

Cited By ~ 1

Author(s):

E.P.J. van den Heuvel

Keyword(s):

Mass Transfer ◽

Binary Systems ◽

Compact Star ◽

Compact Objects ◽

Binary Interaction ◽

X Ray ◽

Tidal Forces ◽

Short Period ◽

Wide Range ◽

The various ways in which compact objects (neutron stars and black holes) can be formed in interacting binary systems are qualitatively outlined on the basis of the three major modes of binary interaction identified by Webbink (1980). Massive interacting binary systems (M1 ≳ 10–12 M⊙) are, after the first phase of mass transfer expected to leave as remnants:(i) compact stars in massive binary systems (mass ≳ 10 M⊙) with a wide range of orbital periods, as remnants of quasi-conservative mass transfer; these systems later evolve into massive X-ray binaries.(ii) short-period compact star binaries (P ~ 1–2 days) in which the companion may be more massive or less massive than the compact object; these systems have high runaway velocities (≳ 100 km/sec) and start out with highly eccentric orbits, which are rapidly circularized by tidal forces; they may later evolve into low-mass X-ray binaries;(iii) single runaway compact objects with space velocities of ~ 102 to 4.102 km/sec; these are expected to be the most numerous compact remnants.Compact star binaries may also form from Cataclysmic binaries or wide binaries in which an O-Ne-Mg white dwarf is driven over the Chandrasekhar limit by accretion.