COOLING OF MAGNETARS WITH INTERNAL COOLING OF MAGNETARS WITH INTERNAL LAYER HEATING LAYER HEATING...
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Transcript of COOLING OF MAGNETARS WITH INTERNAL COOLING OF MAGNETARS WITH INTERNAL LAYER HEATING LAYER HEATING...
COOLING OF MAGNETARS WITH INTERNALCOOLING OF MAGNETARS WITH INTERNAL LAYER HEATINGLAYER HEATING
A.D. Kaminker, D.G. Yakovlev, A.Y. Potekhin, N. Shibazaki*, P. Sternin, and O.Y. Gnedin**
Ioffe Physical Technical Institute, St.-Petersburg, Russia*Rikkyo University, Tokyo 171-8501, Japan **Ohio State University, 760 1/2 Park Street, Columbus, OH 43215, USA
Conclusions
Introduction
Physics input
Cooling calculations
Nanjing 2006.07.25
)(TTT ss
Thermal balance:
Photon luminosity:
Heat blanketingenvelope:
ergsTUT2
94810~Heat content:
Cooling theory with internal heating
Main cooling regulators:
1. EOS2. Neutrino emission3. Reheating processes4. Superfluidity5. Magnetic fields6. Light elements on the surface
42L 4 sR T
Heat transport:
( )dT
C T W L Ldt
;dT
Fdr
- effective thermal conductivity
Direct Urca (Durca) process
e
ep
n
Lattimer, Pethick, Prakash, Haensel (1991)
ee nepepn ,
eenn
dfffwQ epnfi )1)(1(2
npeepn
A Tc
mmmgGQ
6
31022 )31(
10080457
169
4610~ sergTL
Threshold: FeFpFn ppp 02 ~in the inner coresof massive stars
Similar processes with muons : produce
Similar processes with hyperons, e.g.:
n
1369
27103~ scmergTQ
Inner cores of massive neutron stars:
Nucleons,hyperons
Pioncondensates
Kaoncondensates
Quarkmatter
e
e
nep
epn
e
e
nep
epn
~~
~~
e
e
qeq
eqq
~~
~~
e
e
deu
eud
scmerg
TQ 36
927103~
scmerg
TQ 36
9262410~
scmerg
TQ 36
9242310~
scmerg
TQ 36
9242310~
serg
TL 69
4610~
serg
TL 69
444210~
serg
TL 69
424110~
serg
TL 69
424110~
Everywhere in neutron star cores. Most important in low-mass stars.
ModifiedUrca process
Brems-strahlung
e
e
NnNep
NepNn
NNNN
scmerg
TQ 38
9222010~
scmerg
TQ 38
9201810~
serg
TL 89
403810~
serg
TL 89
383610~
,,e
NONSUPERFLUID NEUTRON STARS: Modified URCA versus Direct URCA
EOS: PAL-I-240 (Prakash, Ainsworth, Lattimer 1988)
Magnetars versus ordinary cooling neutron stars
Two assumptions:(1) The magnetar data reflect persistent thermal surface emission(2) Magnetars are cooling neutron stars
There should be a REHEATING!Which we assume to be INTERNAL
1. EOS: APR III (n, p, e, µ) Gusakov et al. (2005) Akmal-Pandharipande-Ravenhall (1998) -- neutron star models
Parametrization: Heiselberg & Hiorth-Jensen (1999)
2. Heat blanketing envelope: 310 /10 cmgb
sb TT -- relation;
)(sT surface temperature,
;4442 dTLTR seff
effT -- effective temperature;
d -- surface element
( )b bT T
21
H
H0
Model of heating:
at 21 10 11 3
1 23 10 ; 10 ;g cm i
12 12 31 210 ; 3 10 ;g cm ii
13 14 31 23 10 ; 10 ;g cm iii
14 32 ; =9 10 ;g cm iv
erg s -1
erg cm -3 s -1
- characteristic time of the heating
No isothermal stage
Core — crust decoupling
yrt 310 1- SGR 1900+142- SGR 0526-663- AXP 1E 1841-045
5- AXP 1RXS J170849-4009106- AXP 4U 0142+617- AXP 1E 2259+586
Only outer layers of heating are appropriate for hottest NSs
4- CXOU J010043.-721134
Direct Urca process included :
Modified Urca process :Duration of heating
Enhanced and weakened thermal conductivity
Appearance of isothermal layers
from tomin =3 x 10 12max =10 14 g cm -3
Necessary energy input vrs. photon luminosity
)(s
erg into the layer W 1 2
THE
THE NATURE OF INTERNAL HEATING
1. The stored energy ETOT=1049—1050 erg is released in t=104—105 years.
2. It can still be the energy of internal magnetic field B=(1—3)x1016 G in the magnetar core.
3. The energy can be stored in the entire star but relesed in the outer crust -- Ohmic dissipation? Generation of waves which dissipate in the outer crust?
}Energy release
Energy storage
Neutrino emission mechanisms in the magnetar outer envelope
No Mechanism Reaction
1 Plasmon decay
2 Electron-positron
pair annihilation
3 Electron-nucleus
bremsstrahlung
4 Photoneutrino
5 Neutrino synchrotron
e e
e Z e Z
e e
2 2 22 5 14 2 5F
SYN B 13 95 7 8 3
2 (5) erg ( ) 9.04 10
9 cm s
e G BQ C k T B T
c
e e
NEUTRINO EMISSION IN THE CRUST AT DIFFERENT TEMPERATURES
MAGNETARS WITH NEUTRINO SYNCHROTRON EMISSION
Conclusions
1. Our main assumption: the heating source is located inside the neutron star
2. The heating source must be close to the surface: 115 10 g cm -3
3. The heat intensity should range:19 20
03 10 3 10H erg cm-3 s-1
4. Heating of deeper layers is extremely inefficient due to neutrino radiation
Pumping huge energy into the deeper layers would not increase 5. sT
6. Strongly nonuniform temperature distribution:
in the heating layer T > 109 K;
the bottom of the crust and the stellar core remain much colder T << 109 K
7. Thermal decoupling of the outer crust from the inner layers
8. The total energy release (during 104 – 105 years)
cannot be lower than 1049—1050 erg;
only 1% of this energy can be spent to heat the surface