Zobrazeno 1 - 10
of 41
pro vyhledávání: '"Medin, Zach"'
Autor:
Medin, Zach, von Steinkirch, Marina, Calder, Alan C., Fontes, Christopher J., Fryer, Chris L., Hungerford, Aimee L.
Publikováno v:
The Astrophysical Journal, 832:102 (24pp), 2016 December 1
The hydrogen and helium accreted by X-ray bursting neutron stars is periodically consumed in runaway thermonuclear reactions that cause the entire surface to glow brightly in X-rays for a few seconds. With models of the emission, the mass and radius
Externí odkaz:
http://arxiv.org/abs/1611.09937
The heavy element ashes of rp-process hydrogen and helium burning in accreting neutron stars are compressed to high density where they freeze, forming the outer crust of the star. We calculate the chemical separation on freezing for a number of diffe
Externí odkaz:
http://arxiv.org/abs/1603.08644
Autor:
Medin, Zach, Cumming, Andrew
We discuss the effect of chemical separation as matter freezes at the base of the ocean of an accreting neutron star, and the subsequent enrichment of the ocean in light elements and inward transport of heat through convective mixing. We extend the s
Externí odkaz:
http://arxiv.org/abs/1409.2533
Autor:
Medin, Zach, Cumming, Andrew
Publikováno v:
Astrophys. J. 783 (2014) L3
We show that convection driven by chemical separation can significantly affect the cooling curves of accreting neutron stars after they go into quiescence. We calculate the thermal relaxation of the neutron star ocean and crust including the thermal
Externí odkaz:
http://arxiv.org/abs/1311.5145
Publikováno v:
Phys. Rev. E 86, 066413 (2012)
The neutron rich isotope 22Ne may be a significant impurity in carbon and oxygen white dwarfs and could impact how the stars freeze. We perform molecular dynamics simulations to determine the influence of 22Ne in carbon-oxygen-neon systems on liquid-
Externí odkaz:
http://arxiv.org/abs/1211.0891
Autor:
Medin, Zach, Cumming, Andrew
Publikováno v:
Astrophys. J. 730 (2011) 97
We discuss the effect of chemical separation as matter freezes at the base of the ocean of an accreting neutron star, and argue that the retention of light elements in the liquid acts as a source of buoyancy that drives a slow but continual mixing of
Externí odkaz:
http://arxiv.org/abs/1011.4701
Autor:
Medin, Zach, Cumming, Andrew
Publikováno v:
Phys. Rev. E 81 (2010) 036107
We develop a method for calculating the equilibrium properties of the liquid-solid phase transition in a classical, ideal, multi-component plasma. Our method is a semi-analytic calculation that relies on extending the accurate fitting formulae availa
Externí odkaz:
http://arxiv.org/abs/1002.3327
Autor:
Medin, Zach, Lai, Dong
Publikováno v:
Mon.Not.Roy.Astron.Soc. 406 (2010) 1379-1404
We present numerical simulations of electron-positron pair cascades in the magnetospheres of magnetic neutron stars for a wide range of surface fields (B_p = 10^{12}--10^{15} G), rotation periods (0.1--10 s), and field geometries. This has been motiv
Externí odkaz:
http://arxiv.org/abs/1001.2365
Autor:
Medin, Zach, Lai, Dong
Publikováno v:
Mon.Not.Roy.Astron.Soc. 382 (2007) 1833-1852
For sufficiently strong magnetic fields and/or low temperatures, the neutron star surface may be in a condensed state with little gas or plasma above it. Such surface condensation can significantly affect the thermal emission from isolated neutron st
Externí odkaz:
http://arxiv.org/abs/0708.3863
Publikováno v:
Mon.Not.Roy.Astron.Soc. 383 (2008) 161-172
Recent observations of thermally emitting isolated neutron stars revealed spectral features that could be interpreted as radiative transitions of He in a magnetized neutron star atmosphere. We present Hartree-Fock calculations of the polarization-dep
Externí odkaz:
http://arxiv.org/abs/0704.1598