Spencer Beloin - Academia.edu (original) (raw)
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Universidad Nacional Autónoma de México
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Papers by Spencer Beloin
I present a quantitative analysis that utilizes observations of neutron stars to constrain the ma... more I present a quantitative analysis that utilizes observations of neutron stars to constrain the magnitude of the neutron superfluid gap and the proton superconducting gap in dense matter. In the context of the minimal cooling model, the most likely range for the neutron triplet superfluid gap is 2.09 −1.41 × 10 K and the most likely range for the the proton singlet superconducting gap is 7.59 −5.81 × 10 K. In a second analysis, I confirm these basic predictions for the gaps and additionally determine the mass and envelope composition of the neutron stars in our data set. This analysis shows that some neutron stars are likely more massive and thus cool by the direct Urca process. It also shows that the minimal cooling model may not be the best explanation of neutron star cooling observations. Finally, these quantitative results show that further observations of neutron star cooling will continue to provide constraints on both the equation of state and the transport properties of dense...
Physical Review C
We present a quantitative analysis of superfluidity and superconductivity in dense matter from ob... more We present a quantitative analysis of superfluidity and superconductivity in dense matter from observations of isolated neutron stars in the context of the minimal cooling model. Our new approach produces the best fit neutron triplet superfluid critical temperature, the best fit proton singlet superconducting critical temperature, and their associated statistical uncertainties. We find that the neutron triplet critical temperature is likely 2.09 +4.37 −1.41 × 10 8 K and that the proton singlet critical temperature is 7.59 +2.48 −5.81 × 10 9 K. However, we also show that this result only holds if the Vela neutron star is not included in the data set. If Vela is included, the gaps increase significantly in order to attempt to reproduce Vela's lower temperature given its young age. Further including neutron stars believed to have carbon atmospheres increases the neutron critical temperature and decreases the proton critical temperature. Our method demonstrates that continued observations of isolated neutron stars can quantitatively constrain the nature of superfluidity in dense matter.
Physical Review C, Nov 5, 2019
Using a model for the equation of state and composition of dense matter and the magnitude of sing... more Using a model for the equation of state and composition of dense matter and the magnitude of singlet proton superconductivity and triplet neutron superfluidity, we perform the first simultaneous fit of neutron star masses and radii determined from observations of quiescent low-mass x-ray binaries and luminosities and ages determined from observations of isolated neutron stars. We find that the Vela pulsar strongly determines the values inferred for the superfluid/superconducting gaps and the neutron star radius. We find, regardless of whether or not the Vela pulsar is included in the analysis, that the threshold density for the direct Urca process lies between the central density of 1.7 and 2 solar mass neutron stars. We also find that two solar mass stars are unlikely to cool principally by the direct Urca process because of the suppression by neutron triplet superfluidity.
I present a quantitative analysis that utilizes observations of neutron stars to constrain the ma... more I present a quantitative analysis that utilizes observations of neutron stars to constrain the magnitude of the neutron superfluid gap and the proton superconducting gap in dense matter. In the context of the minimal cooling model, the most likely range for the neutron triplet superfluid gap is 2.09 −1.41 × 10 K and the most likely range for the the proton singlet superconducting gap is 7.59 −5.81 × 10 K. In a second analysis, I confirm these basic predictions for the gaps and additionally determine the mass and envelope composition of the neutron stars in our data set. This analysis shows that some neutron stars are likely more massive and thus cool by the direct Urca process. It also shows that the minimal cooling model may not be the best explanation of neutron star cooling observations. Finally, these quantitative results show that further observations of neutron star cooling will continue to provide constraints on both the equation of state and the transport properties of dense...
Physical Review C
We present a quantitative analysis of superfluidity and superconductivity in dense matter from ob... more We present a quantitative analysis of superfluidity and superconductivity in dense matter from observations of isolated neutron stars in the context of the minimal cooling model. Our new approach produces the best fit neutron triplet superfluid critical temperature, the best fit proton singlet superconducting critical temperature, and their associated statistical uncertainties. We find that the neutron triplet critical temperature is likely 2.09 +4.37 −1.41 × 10 8 K and that the proton singlet critical temperature is 7.59 +2.48 −5.81 × 10 9 K. However, we also show that this result only holds if the Vela neutron star is not included in the data set. If Vela is included, the gaps increase significantly in order to attempt to reproduce Vela's lower temperature given its young age. Further including neutron stars believed to have carbon atmospheres increases the neutron critical temperature and decreases the proton critical temperature. Our method demonstrates that continued observations of isolated neutron stars can quantitatively constrain the nature of superfluidity in dense matter.
Physical Review C, Nov 5, 2019
Using a model for the equation of state and composition of dense matter and the magnitude of sing... more Using a model for the equation of state and composition of dense matter and the magnitude of singlet proton superconductivity and triplet neutron superfluidity, we perform the first simultaneous fit of neutron star masses and radii determined from observations of quiescent low-mass x-ray binaries and luminosities and ages determined from observations of isolated neutron stars. We find that the Vela pulsar strongly determines the values inferred for the superfluid/superconducting gaps and the neutron star radius. We find, regardless of whether or not the Vela pulsar is included in the analysis, that the threshold density for the direct Urca process lies between the central density of 1.7 and 2 solar mass neutron stars. We also find that two solar mass stars are unlikely to cool principally by the direct Urca process because of the suppression by neutron triplet superfluidity.