Publication: Estructura de la materia en las estrellas de neutrones (Structure of matter in neutron stars)
Loading...
Official URL
Full text at PDC
Publication Date
2011
Authors
Advisors (or tutors)
Editors
Journal Title
Journal ISSN
Volume Title
Publisher
Citations
Exportar
Abstract
Los modelos actuales de la estructura y composición de la materia en las estrellas de neutrones son complejos pues requieren predecir los datos astrofísicos (masa, radio,
parámetros de Kepler en sistema binarios, perfil de las señales de su espectro, etc.) a partir de la ecuación de estado de la materia comprimida. Tras repasar los aspectos
más relevantes de la estructura de la materia en las estrellas de neutrones, se describen 2 resultados originales: (1) Un Test observacional para confirmar la hipótesis de que la corteza de la estrella de neutrones contiene hierro en forma cristalina, para ello se requiere la existencia de una estrella doble de neutrones, compuesta por una estrella de neutrones fría, y su compañera un púlsar o una fuente de rayos X, al objeto de estudiar los patrones de difracción de Bragg que puedan ser observados, y (2) Un cálculo variacional basado en el modelo Cornell del gauge de Coulornb QCD, para mostrar la posibilidad de que los neutrones en la estrella puedan adoptar simetría cúbica a un coste de energía de 150 MeV. Comparando este resultado con la energía libre de Helmhotz obtenida al deformar los neutrones, se infiere un suavizamiento de la ecuación de estado (EoS) de la materia de neutrones. [ABSTRACT] Current theories of Neutron Stars structure and composition are very complex. As very information-rich equations of state (EoS) have to be tested with few astrophysics data (mass, size, pulsar period and time dependence, etc.). After a brief overview of the most relevant issues on the structure of neutrón stars interiors, we here propose two original results: (1) An observational test to confirm the hypotesis that the outer-most layer of the star contains iron in crystalline form, that requires the existence of a double neutron star composed of one cooled-down neutron star and a pulsar or X-ray emitting companion, for studying the resulting Bragg´s diffraction pattern observed, and (2) A variational computation within the Cornell model of Coulomb gauge QCD, to show that neutrons in the star can adopt cubic symmetry at an energy cost of 150 MeV. Balancing this result with the Helmhotz free energy gained by increasing neutron packing, a possible softening of the Equation of State (EoS) of neutron matter would ensue.
Description
Máster de Física Fundamental. Facultad de Ciencias Físicas.
Curso 2010-2011
UCM subjects
Unesco subjects
Keywords
Citation
[l] Baade & Zwicky, 1934, Cosmic rays from supernovae, Proc. Nat. Acad. Sci., 20, 259
[2] Hewish, A., Bell, S.J., Pilkington, J.D., Scott, P.F., & Collins, R.A. 1968, Observation of a Rapidily Pulsating Radio source, Nature, 217, 709
[3] Oppenheimer, J. R. & Volkoff, G. M., (1939) On Massive Neutron Cores, Physical Review, 55, 374
[4] Lattimer, J. M. & Prakash, M. 2010, What a two solar mass Really Means? (arXiv: 1012.3208 [astroph. SR])
[5] Haensel, P., Potekhin, A.Y., and Yakovlev, D. G. Neutron Stars. Equation of State and Structure (Springer, New York, 2007)
[6] Demorest et al., Nature 467, 1081 (2010)
[7] Lavagetto, G. et al. Constraints to the EOS of Ultradense Matter with Model-Independent Astrophysical Observations (arXiv: astro-ph/0612061)
[8] Weber, F. Pulsars as Astrophysical Laboratories for Nuclear and Particles Physics, High Energy Physics, Cosmology and Gravitation Series (IOP, Bristol, Great Britain, 1999)
[9] Becker, W. (ed.) Neutron Stars and Pulsars, Astrophysics and Space Science Library 357, (Springer-Verlag, Berlin, 2009
[l0] Glendenning, N. K. Compact Stars, Nuclear Physics, Particle Physics and General Relativity (Springer, New York, 2000)
[l1] Akmal, A., Pandharipande, V.R., and Ravenhall, D.G. Equation of State of nucleon matter and neutron star structure, Phys. Rev. C 58, 1804 (1998)
[12] Chamel, N.and Haensel, P. Physics of Neutron Stars Crusts (December 2008) (arXiv: 0812.3955v1 [astro-ph])
[13] Leupold, S. et al.: Part I Bulk Properties of Strongly Interactting Matter. Lect. Notes Phys. 814, 39-334 (2011)
[14] Bodmer, A. R., Phys. Rev. D 4 (1971) 1601.
[15] Witten, E., Phys. Rev. D 30 (1984) 272
[16] Hill, H. J. and Paz, G., Phys. Rev. D 82 (2010) 113005, (arXiv:1008.4619-[hep-ph])
[17] Alford, M. G., Schmit, A., Rajagopal, K., and Schafer, T. Color Superconductivity in dense quark matter, (arXiv:0709.4635v2 [hep-ph])
[18] Llanes-Estrada, F. J. and Moreno-Navarro, G. Bragg Difraction and the Iron Crust of cold Neutron Stars to appear in Jour. Astrophys. Space Sci., 2011, (arXiv: 0905.4837v3 [astro-ph.HE])
[19] Llanes-Estrada, F. J. and Moreno-Navarro. G. Cubic Neutrons (arXiv:1108.1859v1 [nucl-th])
[20] Hales, T., Jour. Comp. App. Math. 44, 41 (1992)
[21] Eichten, E., Gottfried, K., Kinoshita, T., Lane, K, and Yan, T.M., Phys. Rev. D17, 3090 (1978).
[22] Torres-Rincón, J. M. and Llanes-Estrada, F. J. Phys. Rev. Lett. 105, 022003 (2010)
[23J Nakamura, K. et al. (Particle Data Group}, J. Phys. G G37, 075021 (2010)
[24J Lacour, A., Oller, J., and Meissner, U. G., Annals Phys. 326, 241 (2011)
[25J Hebeler, K., Lattimer, J, Pethick, C. and Schwenk, A., Phys.Rev.Lett. 105, 161102 (2010) 11