Neutron star envelopes

Gudmundsson, E. H.; Pethick, C. J.; Epstein, Richard I.

doi:10.1086/183840

Cited by 106 publications

(102 citation statements)

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“…similar core temperatures during the neutrino dominated cooling era), those with strong toroidal fields have an apparent effective temperature about a factor 2 smaller than those with low magnetic fields or purely dipolar configurations. Our result can also be compared to the classical formula that relates the temperature at the base of the envelope with the surface temperature (Gudmundsson et al 1982)…”

Section: Effective Temperaturementioning

confidence: 98%

Anisotropic thermal emission from magnetized neutron stars

Pérez-Azorín¹,

Miralles²,

Pons³

2006

A&A

101

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Context. The thermal emission from isolated neutron stars is not well understood. The X-ray spectrum is very close to a blackbody but there is a systematic optical excess flux with respect to the extrapolation to low energy of the best blackbody fit. This fact, in combination with the observed pulsations in the X-ray flux, can be explained by anisotropies in the surface temperature distribution. Aims. We study the thermal emission from neutron stars with strong magnetic fields B ≥ 10 13 G in order to explain the origin of the anisotropy. Methods. We find (numerically) stationary solutions in axial symmetry of the heat transport equations in the neutron star crust and the condensed envelope. The anisotropy in the conductivity tensor is included consistently. Results. The presence of magnetic fields of the expected strength leads to anisotropy in the surface temperature. Models with toroidal components similar to or larger than the poloidal field reproduce qualitatively the observed spectral properties and variability of isolated neutron stars. Our models also predict spectral features at energies between 0.2 and 0.6 keV for B = 10 13 −10 14 .

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Section: Effective Temperaturementioning

confidence: 98%

Anisotropic thermal emission from magnetized neutron stars

Pérez-Azorín¹,

Miralles²,

Pons³

2006

A&A

101

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“…The thermalization and BEC formation of DM in the interior of compact stars depend on significantly the star's internal temperature T c which is largely uncertain in observations. For NSs, following our previous work (Zheng et al 2015), the T c can be estimated from the relatively well-studied NS's surface temperature T s based on the study of thermal structure of the insulating envelope presented by Gudmundsson et al (1982). In particular, Gudmundsson et al (1982) found that the temperature T b measured at inner boundary of the envelope (with density ρ ∼ 10 10 g cm −3 ) can be related to the surface temperature T s as…”

Section: Compact Star Modelsmentioning

confidence: 99%

Strange Quark Stars as a Probe of Dark Matter

Zheng

Chen

2016

ApJ

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We demonstrate that the observation of old strange quark stars (SQSs) can set important limits on the scattering cross sections σ q between the light quarks and the non-interacting scalar dark matter (DM). By analyzing a set of 1403 of solitary pulsarlike compact stars in the Milky Way, we find the old solitary pulsar PSR J1801-0857D can set the most stringent upper limits on σ q or the DM-proton scattering cross sections σ p . By converting σ q into σ p based on effective operator analyses, we show the resulting σ p limit by assuming PSR J1801-0857D to be a SQS could be comparable with that of the current direct detection experiments but much weaker (by several orders of magnitude) than that obtained by assuming PSR J1801-0857D to be a neutron star (NS), which requires an extremely small σ p far beyond the limits of direct detection experiments. Our findings imply that the old pulsars are favored to be SQSs rather than NSs if the scalar DM were observed by future terrestrial experiments.

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“…For constant opacity, the integration gives F ∝ T 4 , but the scaling with temperature can be different when the opacity is temperature and depth dependent. For example, the relation between surface temperature T eff and the temperature deep in the crust at densities of ρ 10 10 g cm −3 is T eff ∝ T 2.2 (Gudmundsson et al 1982). We calculated a series of constant flux temperature profiles in the neutron star envelope to determine the scaling of luminosity with temperature at the base of the layer, L ∝ T γ .…”

Section: Intrinsic Effectsmentioning

confidence: 99%

The cooling rate of neutron stars after thermonuclear shell flashes

Zand

Cumming

Triemstra

et al. 2014

A&A

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Thermonuclear shell flashes on neutron stars are detected as bright X-ray bursts. Traditionally, their decay is modeled with an exponential function. However, this is not what theory predicts. The expected functional form for luminosities below the Eddington limit, at times when there is no significant nuclear burning, is a power law. We tested the exponential and power-law functional forms against the best data available: bursts measured with the high-throughput Proportional Counter Array (PCA) onboard the Rossi X-ray Timing Explorer. We selected a sample of 35 "clean" and ordinary (i.e., shorter than a few minutes) bursts from 14 different neutron stars that 1) show a wide dynamic range in luminosity; 2) are the least affected by disturbances by the accretion disk; and 3) lack prolonged nuclear burning through the rp-process. We find indeed that for every burst a power law is a better description than an exponential function. We also find that the decay index is steep, 1.8 on average, and different for every burst. This may be explained by contributions from degenerate electrons and photons to the specific heat capacity of the ignited layer and by deviations from the Stefan-Boltzmann law due to changes in the opacity with density and temperature. Detailed verification of this explanation yields inconclusive results. While the values for the decay index are consistent, the predicted dependency of the decay index with the burst time scale, as a proxy of ignition depth, is not supported by the data.

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Neutron star envelopes

Cited by 106 publications

References 0 publications

Anisotropic thermal emission from magnetized neutron stars

Anisotropic thermal emission from magnetized neutron stars

Strange Quark Stars as a Probe of Dark Matter

The cooling rate of neutron stars after thermonuclear shell flashes

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