Neutron star cooling: theoretical aspects and observational constraints

Yakovlev, D. G.; Gnedin, Oleg Y.; Kaminker, A. D.; Levenfish, K. P.; Potekhin, A. Y.

doi:10.1016/j.asr.2003.07.020

Cited by 57 publications

(75 citation statements)

References 42 publications

(43 reference statements)

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“…2. Thick dashed lines show proton gaps which were used in the work of [9] performed in the framework of the "standard plus exotics" scenario. We will call the choice of the "3nt" model from [9] the model I.…”

Section: Cooling Evolution Of Hadronic Starsmentioning

confidence: 99%

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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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Section: Cooling Evolution Of Hadronic Starsmentioning

confidence: 99%

“…[6,7], i.e., if one includes medium effects into consideration. In the "standard plus exotics" scenario for hadronic models the in-medium effects have not been incorporated, see [8,9,10]. Recently [10] called this approach the "minimal cooling" paradigm.…”

Section: Introductionmentioning

confidence: 99%

Cooling Evolution of Hybrid Stars

Grigorian¹

2005

AIP Conference Proceedings

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Section: Introductionmentioning

confidence: 99%

“…We exclude only models V and II from our present discussion, since they are not in our aimed class of models. The remaining models selected are defined in Table I by the choice of the nucleon pairing gaps: (A) models I, IX -gaps from [28]; (B) models III, VI, IV, VII, VIII -gaps from [11]. For all models the 3 P 2 neutron gap is suppressed by 0.1; see Refs.…”

mentioning

confidence: 99%

“…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 into account.The choice of the structure of crust and envelope of the compact object becomes a central question due to the direct connection of the surface temperature with the observations. Since simultaneous measurements of the surface temperature and either the mass or the radius of neutron stars are absent, one needs to relate the known TA data with other observational information in order to discriminate between different models.…”

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confidence: 99%

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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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PSR J1119–6127 and the X-ray emission from high magnetic field radio pulsars

Gonzalez¹,

Kaspi²,

Camilo³

et al. 2007

Isolated Neutron Stars: From the Surface to the Interior

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The existence of radio pulsars having inferred magnetic fields in the magnetar regime suggests that possible transition objects could be found in the radio pulsar population. The discovery of such an object would contribute greatly to our understanding of neutron star physics. Here we report on unusual X-ray emission detected from the radio pulsar PSR J1119-6127 using XMMNewton. The pulsar has a characteristic age of 1,700 yrs and inferred surface dipole magnetic field strength of 4.1×10 13 G. In the 0.5-2.0 keV range, the emission shows a single, narrow pulse with an unusually high pulsed fraction of ∼70%. No pulsations are detected in the 2.0-10.0 keV range, where we derive an upper limit at the 99% level for the pulsed fraction of 28%. The pulsed emission is well described by a thermal blackbody model with a high temperature of ∼2.4×10 6 K. While no unambiguous signature of magnetar-like emission has been found in high-magnetic-field radio pulsars, the X-ray characteristics of PSR J1119-6127 require alternate models from those of conventional thermal emission from neutron stars. In addition, PSR J1119-6127 is now the radio pulsar with the smallest characteristic age from which thermal X-ray emission has been detected.

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Neutron star cooling: theoretical aspects and observational constraints

Cited by 57 publications

References 42 publications

Cooling Evolution of Hybrid Stars

Cooling Evolution of Hybrid Stars

Brightness constraint for cooling models of young neutron stars

PSR J1119–6127 and the X-ray emission from high magnetic field radio pulsars

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