New insights from a global view of X-ray bursts

Fushiki, Ikko; Lamb, D. Q.

doi:10.1086/185056

Cited by 105 publications

(158 citation statements)

References 0 publications

Supporting

Mentioning

146

Contrasting

Order By: Relevance

“…This indicates that the FB consists of unstable nuclear burning on the neutron star. In the theory of unstable nuclear burning (Fujimoto et al 1981;Fushiki & Lamb 1987;Bildsten 1998;Schatz et al 1999) the physical conditions in the atmosphere of the neutron star depend on the mass accretion rate per unit areaṁ, i.e.Ṁ divided by the emitting area. The various régimes of stable and unstable burning are shown in Table 2.…”

Section: Discussionmentioning

confidence: 99%

On the nature of the Cygnus X-2 like Z-track sources

Bałucińska‐Church

Gibiec

Jackson³

et al. 2010

A&A

View full text Add to dashboard Cite

Based on the results of applying the extended ADC emission model for low mass X-ray binaries to three Z-track sources: GX 340+0, GX 5-1 and Cyg X-2, we propose an explanation of the Cygnus X-2 like Z-track sources. The Normal Branch is dominated by the increasing radiation pressure of the neutron star caused by a mass accretion rate that increases between the soft apex and the hard apex. The radiation pressure continues to increase on the Horizontal Branch becoming several times super-Eddington. We suggest that this disrupts the inner accretion disk and that part of the accretion flow is diverted vertically forming jets which are detected by their radio emission on this part of the Z-track. We thus propose that high radiation pressure is the necessary condition for the launching of jets. On the Flaring Branch there is a large increase in the neutron star blackbody luminosity at constant mass accretion rate indicating an additional energy source on the neutron star. We find that there is good agreement between the mass accretion rate per unit emitting area of the neutron starṁ at the onset of flaring and the theoretical critical value at which burning becomes unstable. We thus propose that flaring in the Cygnus X-2 like sources consists of unstable nuclear burning. Correlation of measurements of kilohertz QPO frequencies in all three sources with spectral fitting results leads to the proposal that the upper kHz QPO is an oscillation always taking place at the inner accretion disk edge, the radius of which increases due to disruption of the disk by the high radiation pressure of the neutron star.

show abstract

Section: Discussionmentioning

confidence: 99%

On the nature of the Cygnus X-2 like Z-track sources

Bałucińska‐Church

Gibiec

Jackson³

et al. 2010

A&A

View full text Add to dashboard Cite

show abstract

“…Hansen & Van Horn (1975) estimated stability of H and He burning in envelopes of neutron stars by comparison of the characteristic time scale of thermonuclear heating with characteristic time scales for removal of energy from the shell by radiative and conductive thermal diffusion. Fushiki & Lamb (1987) introduced a differential criterion for such estimates. They defined the boundary of thermal stability of the nuclear burning from the condition…”

Section: Conductive Coolingmentioning

confidence: 99%

“…Therefore, the outer envelopes are considered quasistationary for most of the astrophysical problems, and their thermal structure is calculated at stationary equilibrium (Gudmundsson et al 1983). In particular, Fushiki & Lamb (1987) applied this approximation to the stability analysis of H and He shells of accreting neutron stars, and Brown & Bildsten (1998) and Cumming & Bildsten (2001) applied it to the stability analysis of carbon shells. The problem is that Eq.…”

Section: Conductive Coolingmentioning

confidence: 99%

“…Ignition of degenerate carbon and oxygen in the interiors of white dwarfs gives rise to Type Ia supernovae (Hoyle & Fowler 1960;Hillebrandt & Niemeyer 2000). Nuclear reactions in degenerate envelopes of accreting neutron stars are responsible for X-ray bursts and for the overall chemical and thermal structure of the envelopes (Fushiki & Lamb 1987;Brown & Bildsten 1998). Nuclear fusion rates in the interiors of degenerate stars can be significantly enhanced over the binary Gamow (1928) rates because of the many-body screening effect in the dense plasma (Schatzman 1948; for reviews, see Yakovlev & Shalybkov 1989;and Ichimaru 1993).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thermonuclear fusion in dense stars

Potekhin

Chabrier

2012

A&A

View full text Add to dashboard Cite

We study the plasma correlation effects on nonresonant thermonuclear reactions of carbon and oxygen in the interiors of white dwarfs and liquid envelopes of neutron stars. We examine the effects of electron screening on thermodynamic enhancement of thermonuclear reactions in dense plasmas beyond the linear mixing rule. Using these improved enhancement factors, we calculate carbon and oxygen ignition curves in white dwarfs and neutron stars. The energy balance and ignition conditions in neutron star envelopes are evaluated, taking their detailed thermal structure into account. The result is compared to the simplified "one-zone model", which is routinely used in the literature. We also consider the effect of strong magnetic fields on the ignition curves in the ocean of magnetars.

show abstract

“…Edd (see Fushiki & Lamb 1987). It is important to realize that the above quotedṀ values from flash theory are presumed to sustain for at least a few months (i.e., the thermal time scale of the crust).…”

Section: Limits From Theorymentioning

confidence: 99%

Restless quiescence: thermonuclear flashes between transient X-ray outbursts

Kuulkers¹,

Zand

Lasota

2009

A&A

View full text Add to dashboard Cite

For thermonuclear flashes to occur on neutron-star surfaces, fuel must have been accreted from a donor star. However, sometimes flashes are seen from transient binary systems when they are thought to be in their quiescent phase, during which no accretion, or relatively little, is expected to occur. We investigate the accretion luminosity during several such flashes, including the first-ever and brightest detected flash from Cen X-4 in 1969. We infer from observations and theory that immediately prior to these flashes the accretion rate must have been between about 0.001 and 0.01 times the equivalent of the Eddington limit, which is roughly 2 orders of magnitude less than the peak accretion rates seen in these transients during an X-ray outburst and 3-4 orders of magnitude more than the lowest measured values in quiescence. Furthermore, three such flashes, including the one from Cen X-4, occurred within 2 to 7 days followed by an X-ray outburst. A long-term episode of enhanced, but low-level, accretion is predicted near the end of the quiescent phase by the disk-instability model, and may thus have provided the right conditions for these flashes to occur. We discuss the possibility of whether these flashes acted as triggers of the outbursts, signifying a dramatic increase in the accretion rate. Although it is difficult to rule out, we find it unlikely that the irradiance by these flashes is sufficient to change the state of the accretion disk in such a dramatic way.

show abstract

New insights from a global view of X-ray bursts

Cited by 105 publications

References 0 publications

On the nature of the Cygnus X-2 like Z-track sources

On the nature of the Cygnus X-2 like Z-track sources

Thermonuclear fusion in dense stars

Restless quiescence: thermonuclear flashes between transient X-ray outbursts

Contact Info

Product

Resources

About