Cooling of hybrid neutron stars and hypothetical 
 self-bound objects with superconducting quark cores

Blaschke, D.; Grigorian, H.; Voskresensky, D. N.

doi:10.1051/0004-6361:20010005

Cited by 82 publications

(86 citation statements)

References 26 publications

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“…Consequently, it would be interesting to study the neutrino emission from quark matter in the mCFL phase as it provides the quark core with significant μ e (Rüster et al 2005), as well as suppressed quark interactions. Unfortunately, the pairing between quarks decreases the quark heat capacity by exp (−Δ(T )/T ), where Δ is the gap energy (Blaschke et al 2001). For high values of Δ, c q is lowered drastically.…”

Section: Effects Of Colour-superconductivitymentioning

confidence: 99%

Pulsar kicks by anisotropic neutrino emission from quark matter in strong magnetic fields

Sagert¹,

Schaffner-Bielich²

2008

A&A

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Aims. We critically discuss a pulsar acceleration mechanism based on asymmetric neutrino emission from the direct quark Urca process in the interior of proto neutron stars. Methods. The neutrinos are emitted by the cooling strange quark matter core with an anisotropy caused by a strong magnetic field. We calculate the kick velocity of the proto neutron star in dependence of the temperature and radius of the quark phase. The results are compared with the necessary magnetic field strength, as well as the neutrino mean free path. Results. We find that within a quark phase radius of 10 km and temperatures higher than 5 MeV kick velocities of 1000 km s −1 can be reached only when neutrino quark scattering is ignored. When taking the neutrino mean free paths in quark matter into account kick velocities higher than 100 km s −1 cannot be reached. The same holds even when effects from colour superconductivity are included. For pulsar kicks powered by quark phase transitions from an ungapped quark phase to the CFL phase the final velocity depends crucially on the pairing gap and the quark chemical potential and reaches 1000 km s −1 only in marginal cases. Conclusions. We find that the phenomenon of pulsar kick velocities higher than 100 km s −1 cannot be explained by asymmetric neutrino emission from either cooling normal strange quark or colour superconducting quark matter due to the small neutrino mean free paths. If neutrinos are produced by a phase transition to colour-superconducting quark matter, high kick velocities can only be reached for temperatures below 1 MeV.

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Section: Effects Of Colour-superconductivitymentioning

confidence: 99%

Pulsar kicks by anisotropic neutrino emission from quark matter in strong magnetic fields

Sagert¹,

Schaffner-Bielich²

2008

A&A

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“…This code was originally constructed for the description of hybrid stars by [24]. The main cooling regulators are the thermal conductivity, the heat capacity and the emissivity.…”

Section: Coolingmentioning

confidence: 99%

“…The possibility of the existence of neutron stars with large quark matter cores is also not excluded [2,22,23,24]. In the quark matter the DU process yielding the rapid cooling may arise on interacting but unpaired quarks [25] In this review we want to sketch a scenario for the cooling of hybrid stars.…”

Section: Introductionmentioning

confidence: 99%

Cooling Evolution of Hybrid Stars

Grigorian¹

2005

AIP Conference Proceedings

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Abstract. The cooling of compact isolated objects for different values of the gravitational mass has been simulated for two alternative assumptions. One is that the interior of the star is purely hadronic [1] and second that the star can have a rather large quark core [2]. It has been shown that within a nonlocal chiral quark model the critical density for a phase transition to color superconducting quark matter under neutron star conditions can be low enough for these phases to occur in compact star configurations with masses below 1.3 M ⊙ . For a realistic choice of parameters the equation of state (EoS) allows for 2SC quark matter with a large quark gap ∼ 100 MeV for u and d quarks of two colors that coexists with normal quark matter within a mixed phase in the hybrid star interior. We argue that, if in the hadronic phase the neutron pairing gap in 3P 2 channel is larger than few keV and the phases with unpaired quarks are allowed, the corresponding hybrid stars would cool too fast.Even in the case of the essentially suppressed 3P 2 neutron gap if free quarks occur for M < 1.3 M ⊙ , as it follows from our EoS, one could not appropriately describe the neutron star cooling data existing by today.It is suggested to discuss a "2SC+X" phase, as a possibility to have all quarks paired in two-flavor quark matter under neutron star constraints, where the X-gap is of the order of 10 keV -1 MeV. Density independent gaps do not allow to fit the cooling data. Only the presence of an X-gap that decreases with increase of the density could allow to appropriately fit the data in a similar compact star mass interval to that following from a purely hadronic model.

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“…In these approaches the main cooling process is the modified Urca process, which in our NMC scenario also includes the in-medium softening of the pion propagator [4]. Earlier investigations within this cooling scenario [5,6] have chosen the crust model as a simplified Tsuruta law T Tsur s = (10 T in ) 2/3 . Although it is shown in Ref.…”

Section: Introductionmentioning

confidence: 99%

“…The heat conductivity κ, the total neutrino emissivity ǫ ν and the total specific heat c V /n are given as the sum of the corresponding partial contributions defined for density profiles n(r) of the constituents of the matter under the conditions of the actual temperature profile T (r, t). The mass of the star is the accumulated mass below the surface, M = m(r = R), which together with the gravitational potential φ(r) can be determined by Oppenheimer-Volkov equations (see [6,20]), where the energy density profile ε = ε(r) and the pressure profile p = p(r) are defined by the condition of hydrodynamical equilibrium. The boundary condition for the solution of (1) reads T (r = R in , t) = T in (t).…”

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confidence: 99%

Brightness constraint for cooling models of young neutron stars

Grigorian

2006

Phys. Rev. C

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We study the systematics of neutron star cooling curves with three representative masses from the most populated interval of the estimated mass distribution for compact objects. The cooling simulations are made in the framework of the nuclear medium cooling (NMC) scenario using different combinations of possible nucleon-nucleon pairing gaps. Possible heating or enhanced cooling mechanisms in the crust are not considered. We define a constraint on the highest possible temperatures for a given age of young neutron stars and show that this limits the freedom of modeling pairing gaps and crust properties.Typeset using REVT E X 1 Studies of neutron star cooling evolution become very actual due to the presently known surface temperature and age data provided by X-ray observatories such as CHANDRA, XMM Newton and from the ROSAT catalogue [1]. These new data open a wide perspective for nuclear astrophysics for which up to now the knowledge of internal structure of the compact stars and the properties of stellar matter under extreme conditions remain central problems. Theoretical models and hypotheses about the equation of state of high density matter provide different alternatives for the explanation of the same set of observational temperature -age (TA) data points, when additional constraints are not provided. In this work we point out an existing correlation between the crust model and cooling behaviour of light neutron stars, which has a selective power in combination of TA data with the mass spectrum of neutron stars.In our recent investigations of the cooling evolution of neutron stars (NS) we have adopted the so called nuclear medium cooling (NMC) scenario [2], which goes beyond the minimal cooling scenario [3], where in-medium modifications of cooling regulators by definition have been disregarded. Both approaches agree in the philosophy that such very effective cooling mechanism like the direct Urca process should not occur in typical NS. In these approaches the main cooling process is the modified Urca process, which in our NMC scenario also includes the in-medium softening of the pion propagator [4]. Earlier investigations within this cooling scenario [5,6] have chosen the crust model as a simplified Tsuruta law T Tsur s = (10 T in ) 2/3 . Although it is shown in Ref. [7] that the cooling evolution could be essentially affected by the inclusion of internal heating, nevertheless the latter is expected to be important for late time evolution and will not affect the results of this paper. It has been omitted in the present cooling scenario. For more recent reviews on the cooling scenarios see [8][9][10].The cooling simulations presented in this work are based on a code with a number of improved inputs concerning the heat conductivity, the nucleon-nucleon pairing gaps and a new model of the neutron star crust and envelope. These models are basically taken from the recent calculations of Ref. [11], where the amount of light elements in the crust and the 2 influence of the magnetic field have been taken int...

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Cooling of hybrid neutron stars and hypothetical self-bound objects with superconducting quark cores

Cited by 82 publications

References 26 publications

Pulsar kicks by anisotropic neutrino emission from quark matter in strong magnetic fields

Pulsar kicks by anisotropic neutrino emission from quark matter in strong magnetic fields

Cooling Evolution of Hybrid Stars

Brightness constraint for cooling models of young neutron stars

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