COOLING OF N COOLING OF N EUTRON ST EUTRON ST A A R R S S D.G. Yakovlev Ioffe Physical Technical Institute, St.-Petersburg, Russia Huntsville – May – 2009 • Introduction • Neutrino emission • Cooling theory • Phenomenological concept • Theory and observation • Connections • Conclusions Main collaborators: • A.D. Kaminker, Ioffe Institute • A.Y. Potekhin, Ioffe Institute
COOLING OF N EUTRON ST A R S. D.G. Yakovlev. Ioffe Physical Technical Institute, St.-Petersburg, Russia. Introduction Neutrino emission Cooling theory Phenomenological concept Theory and observation Connections Conclusions. Main collaborators: A.D. Kaminker, Ioffe Institute - PowerPoint PPT Presentation
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
COOLING OF NCOOLING OF NEUTRON STEUTRON STAARRS S
D.G. Yakovlev
Ioffe Physical Technical Institute, St.-Petersburg, Russia
Huntsville – May – 2009
• Introduction• Neutrino emission• Cooling theory• Phenomenological concept• Theory and observation• Connections• Conclusions
Main collaborators:• A.D. Kaminker, Ioffe Institute• A.Y. Potekhin, Ioffe Institute
Cooling Theory: Primitive and complicated at once
OVERALL STRUCTURE OF A NEUTRON STAR
Four main layers:1. Outer crust2. Inner crust3. Outer core4. Inner core
The main mystery:1. Composition of the core+2. The pressure of densematter=The problem ofequation of state (EOS)
Basic Ideas
48 29
Heat content:
~ 10TU T ergs
Main cooling regulators
Neutrino emission in neutron star cores
EOS, composition of matterSuperfluidity
Heat content and conduction in cores
Heat capacityThermal conductivity
Thermal conduction in heat blanketing envelopes
Thermal conductivityChemical compositionMagnetic field
Internal heat sources (for old stars and magnetars)
Viscous dissipation of rotational energyOhmic decay of magnetic fields, ect.
e
ep
n
, e e e en p e p e n n n
dfffwQ epnfi )1)(1(2
npeepn
A Tc
mmmgGQ
6
31022 )31(
10080457
27 6 3 19
46 6 19
~ 3 10
~ 10
Q T erg cm s
L T erg s
FeFpFn ppp 02 ~
n
Strongest Neutrino Emission: Direct Urca Process
Lattimer, Pethick, Prakash, Haensel (1991)
Threshold:In inner cores of massive stars
Similar processes with muons
Similar processes with hyperons, e.g.
Is forbidden in outer core by momentum conservation:
0 9 330 MeV/c, 120 MeV/c, ~ / ~ 0.1 MeV/cFn Fe Fp Bp p p p k T c T
Enhanced emission in inner cores of massive neutron stars
Everywhere in neutron star cores
Neutrino Emission Processes in Neutron Star Cores
6 6FAST 0F 9 FAST 0F 9 Q Q T L L T
Model Process
N/H direct Urca
Pion condensate
Kaon condensate
Quark matter
3 10 [erg cm s ]Q
e eN N e N e N
e eB B e B e B
e ed u e u e d
e eB B e B e B 26 2710 3 10 23 2610 1023 2410 1023 2410 10
8 8SLOW 0S 9 FAST 0S 9 Q Q T L L T
Modified Urca
Bremsstrahlung
nN pNe pNe nN
N N N N
20 2110 3 10
19 2010 10
Direct Urca, N/H
Neutrino Emission Processes in Neutron Star CoresOuter core Inner coreSlow emission Fast emission
}
}
}}
}
e en p e p e n
Pion condensate
Kaon condensation
Or quark matter
e eN N e N e N
e eB B e B e B
e ed u e u e d
Modified Urca nN pNe pNe nN
NN bremsstrahlung N N N N
Enhanced emission in inner cores of massive neutron stars:
After Lombardo & Schulze (2001)A=Ainsworth, Wambach, Pines (1989)S=Schulze et al. (1996)W=Wambach, Ainsworth, Pines (1993)C86=Chen et al. (1986)C93=Chen et al. (1993)
Broadening of threshold for fast neutrino emission
Superfluidity:
Suppresses ordinary neutrino processesInitiates Cooper-pairing neutrino emissionShould be: Strong in outer core to suppress modified Urca Penetrate into inner core to broaden direct Urca thresholdCan be: proton or neutron
E.,g. pion polarizationVoskresensky &Senatorov (1984, 1986)Schaab et al. (1997)
Magnetic broadening Baiko & Yakovlev (1999)
Nuclear physics effects
Effects of accreted envelopes and surface magnetic fields
Different mass / of
accreted material on the surface
M M Dipole magnetic field
in heat blanketing layer
SUMMARY OF CONNECTIONS
Objects Physics which is tested
Middle-aged isolated NSa Neutrino luminosity function
Composition and B-field in heat-blanketing envelopes
Young isolated NSs Crust
Quasistationary XRTs Neutrino luminosity function
Composition and B-field in heat-blanketing envelopes
Deep crustal heating
Quasipersistent XRTsKS 1731—260; MXB 1659—29
Crust
Deep crustal heating
Superbursts Crust
Magnetars after outbursts Crust
Magnetars in quasistationary
states
??
CONCLUSIONS
TodayCooling neutron stars Soft X-ray transients
• Constraints on slow and fast neutrino emission levels• Mass ordering
CONCLUSIONSOrdinary cooling isolates neutron stars of age 1 kyr—1 Myr
• There is one basic phenomenological cooling concept (but many physical realizations)• Main cooling regulator: neutrino luminosity function • Warmest observed stars are low-massive; their neutrino luminosity seems to be <= 1/30 of modified Urca• Coldest observed stars are more massive; their neutrino luminosity should be > 30 of modified Urca (any enhanced neutrino emission would do)• Neutron star masses at which neutrino cooling is enhanced are not constrained• The real physical model of neutron star interior is not selected
Connections
• Directly related to neutron stars in soft X-ray transients (assuming deep crustal heating). From transient data the neutrino luminosity of massive stars is enhanced by direct Urca or pion condensation • Related to magnetars and superbusrts
Future
• New observations and accurate theories of dense matter• Individual sources and statistical analysis