Exploring interior of neutron star through neutron star cooling ntroduction hermal evolution of neutron stars -Basic concepts of cooling curve of neutron sta Neutrino luminosity as a probe of new form of ma inside neutron stars Observation of Cas A and nucleon superfluidity Summary and concluding remarks T. Tatsumi (Kyoto U.)
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Exploring interior of neutron star through neutron star cooling
Exploring interior of neutron star through neutron star cooling. T. Tatsumi (Kyoto U.). Introduction Thermal evolution of neutron stars -Basic concepts of cooling curve of neutron stars III. Neutrino luminosity as a probe of new form of matter inside neutron stars - PowerPoint PPT Presentation
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Exploring interior of neutron star through neutron star cooling
I. IntroductionII. Thermal evolution of neutron stars -Basic concepts of cooling curve of neutron starsIII. Neutrino luminosity as a probe of new form of matter inside neutron stars IV Observation of Cas A and nucleon superfluidityV Summary and concluding remarks
T. Tatsumi (Kyoto U.)
I. Introduction 3 14 30 0.16fm 2.8 10 g cm
crust core
Structure of neutron stars
M-R relation (Bulk properties of neutron stars)Cooling curve (Thermal evolution)
curveP P (Magnetic evolution)
EOS (Equation of state) gives
Can microphysics understand or explain these observables ?
・ There have been measured various observables about neutron stars , and great progress in observational technique.・ Unfortunately, most of phenomena occurs near the surface , and can provide us with indirect information about interiors of neutron stars, especially the core region, except their bulk properties.・ Among them neutron star cooling can give direct information of properties of matter at high densities through neutrino emission.
Magnetars (1985)
Dipole radiationFastest pulsar: PSR 1987+21
=1.557 806 448 872 75 0.000 000 000 000 03 msP ±
J. Lattimer, arXiv:1305.3510
(P. B. Demorest, Nature 467, 1081, 2010)
J. Antoniadis et al. Science 340 (2013) 6131
1.97 0.04M
R.A. Hulse and J.H. Taylor, Ap J. !95(1975) L51.
(P. B. Demorest, Nature 467, 1081, 2010)
D.Page, arXiv:1206.5011Comparison with observation
Crab
Cas A
3C 58
Vela
1010 K 1MeV
2 810 (10 K) (0.01MeV)in eT T O O
Cas A
Young pulsars
II. Thermal evolution of neutron stars
(+H)
99 /10 (K)T T
(crust)
Cold catalyzed matter: ・ chemical equilibrium ・ charge neutrality
nFp
pFp
eFp
triangle condition:
Ex) n,p,e matter
Direct URCA (b decay) cycle is strongly suppressed in normal neutron star matter.
,e
e
n p e
p e n
e
N N
Modified URCA
( ),n p e
p e
n p e
n n
2 2( ) ( )
2 2
n peF FF
N N
p p pm m
p eF Fp p
3 14 3
0
2/30
2/30
0.16fm 2.8 10 g cm
60( / ) MeV,
340( / ) MeV,
e pF F
nF
p p
p
( )O T
For free particles
' ,
'e
e
N n N p e
N p e N n
2 810 (10 K) (0.01MeV)in eT T O O
dEthdt
CVdTdt
L L
dTdt
q0
cV 0
T 7 t t0 A 1T 6
1T0
6
T t 1/6
CV 43 R3 cV0 T
L 43 R3 q0 T 8
L 4R2 Te4 T 2 [1]
Neutrino Cooling era: L >> L
Photon Cooling era: L<< L
dTdt
T 1 t t0 B 1T
1T0
T t 1/
Basic Cooling: neutrino vs photon cooling eras
No superfluidMURCA(slow cooling)
D.G. Yakovlev and C.J. Pethick, Ann. Rev. Astron. Astrophys. 42 (2004) 169.
3C58
Relaxation Neutrino cooling Photon cooling
8Q T 4Q T “Standard” scenario
III. Neutrino luminosity as a probe of new form of matter inside neutron stars
Fast coolingExotic cooling
New form of matter
Standard cooling
Modified URCA+photon(+superfluidity) Slow cooling
for 3C58, Vela
New form of matter or Various phases inside neutron stars
Strange Quark Matter
Boson Condensate
Hyperonic Matter
Quark Matter
-30 0.16 fm
02-3
0
Kπ
ΣΛ
uds
uds
Inner cores of massive neutron stars:
Nucleons,hyperons
Pioncondensates
Kaoncondensates
Quarkmatter
e
e
nepepn
e
e
nepepn
~~~~
e
e
qeqeqq
~~~~
e
e
deueud
scmergTQ 3
69
27103~
scmergTQ 3
69
262410~
scmergTQ 3
69
242310~
scmergTQ 3
69
242310~
sergTL 6
94610~
sergTL 6
9444210~
sergTL 6
9424110~
sergTL 6
9424110~
Everywhere in neutron star cores. Most important in low-mass stars.
ModifiedUrca process
Brems-strahlung
e
e
NnNepNepNn
NNNN
scmergTQ 3
89
222010~
scmergTQ 3
89
201810~
sergTL 8
9383610~
,,e
sergTL 8
9403810~
Fast cooling vs slow cooling
Exotic cooling – Impact of 3C58
3C58 is the remnant of a supernova observed in the year 1181 by Chinese and Japanese astronomers. A long look by Chandra shows that the central pulsar - a rapidly rotating neutron star formed in the supernova event - is surrounded by a bright torus of X-ray emission. An X-ray jet erupts in both directions from the center of the torus, and extends over a distance of a few light years. Further out, an intricate web of X-ray loops can be seen.
(NASA,2004)
3C58
CONCLUSIONSabout the
THEORY • EOS quite well determined
• The mass of the star has little impact
• The dominant neutrino emission process is from the formation and breaking of Cooper pairs from the neutron 3P2 gap (unless this gap is very small)
• Possibility of the presence of light elements in the envelope allows to accommodate a range of Te at a given age
S. Tsuruta et al., Ap.J. 571 (2002) L143.c
e
h’
h6
pionQ aT
K.G.Elshamouty et al.,arXiV:1306.3387
NASA
W.C.G. Ho et al, Nature 462 (2009) 71
IV. Observation of Cas A and nucleon superfluidity
/ several %/10years!T T
D.Page, arXiv:1206.5011
Cas A
3C58
Predictions for the NEUTRON 1S0 gap
Medium polarizationeffect O(1/3)
Important feature:
WE DO NOT REALLY KNOW WHAT IT IS
Medium polarization effects were expected to increase the 3P2 gap while they probably strongly suppress it.
32neutron gapP
D. Page et al., astro-ph/0508056D.G. Yakovlev and C.J. Pethick, Ann. Rev. Astron. Astrophys. 42 (2004) 169.
Cooling of compact stars and superfluidity
・ Enhancement of neutrino luminosity・ Suppression by the pairing
New form of matter
/Te
norma
*2normal
2
paired normal
pa
l /
//normae lir d
e.g. :
C (0) , (0)3
( / )
( ex) Durca process):
specific heat
luminosit
y
, pn
TV
FV
V
TT
V c
e e
m pN T N
C C M T T
n p e e
C e
n
L e e
p
L
Neutrino cooling era Photon cooling era
Note: , (modified URCA) is suppressed by the factor, exp( / ), for each Fermion through the suppression of the phase space,while receives no effec
/
t.
V
VC L T tC L
T
L
Neutrino emission through the formation and breaking of Cooper pairs (PBF)
Flowers, Ruderman & Sutherland, Ap. J. 205 (1976), 541