Sec on 10.
Mechanism of core-collapse supernovae
10.1 Core-collapseti

10.2 Mechanism of core-collapse supernovae

Let’s understand these ques ons
with the words of physics• Why are stars so luminous?
• Why do stars show L ~ M ?
• Why do stars evolve?
• Why does the des ny of stars depend on the mass?
• Why do some stars explode?
• Why don’t normal star explode?
• Why does stellar core collapses?
• Why is the energy of supernova so huge?
•…
titi

4

Neutron starorBlack holeCollapse(< 1 sec)Supernova!

What triggers the collapse of the star??

Sec on 10.
Mechanism of core-collapse supernovae
10.1 Core-collapseti

10.2 Mechanism of core-collapse supernovae

Results of simula ons (1D)SUMIYOSHI ET AL.

Vol. 629

Sumiyoshi+05

Radius (km)ShockFailure
1 sec
Time (s)ti(thick lines) and LS (thin lines) as a function of time after bounce. The evolution at early (left) and late (right)

fiffiWhy do stars nally explode?
Why is it di cult to reproduce explosions?

ν(1)

(2)

Neutrino trapping

Core-collapseνeFeνν νν

Fe coreννν	ShockSN neutrinoν"νν ννν ννν ννν ννν(3)νCore bounce
図 1.4(4)(5)

Supernova

Neutron star(C) 原子核から読み解く超新星爆発の世界

重力崩壊型超新星の爆発メカニズムの概要．重い星の中心部にある鉄住吉光介さん著 (Kosuke Sumiyoshi)
コアの重力崩壊から始まり，密度・温度が高まる中で発生したニュー(C) A. Burrows

Suwa et al. 2011

Suwa et al.
Suwa et al. 2011

RadiusRadius (km)
[km]

1000

Shock
1D simula on

1000.4 sec
10050

100 150 200 250 300 350 400 450Time（msec）
Timeafter bounce [ms]ti

E ~ 1050 erg (smaller than observa ons by 1 order of magnitude)
Fig. 1. Time evolution of Models M13-1D and M13-2D, v
Oneof the bybiggest
in moderninastrophysics
sualizedmassmysteryshell trajectories
thin gray and orangti07a).
pears
ssive
er ofoups.
ave a09).
modmotoatinga exironpro2006)
m 2D
sport[VSN 1987A(in Large Magellanic cloud, 50 kpc)

Neutrino detec on
From SN 1987A
Kamiokandeti(C) ICRR

nsion between KAMIOKANDE and IMB data

Enu ~ 1053 erg!!
=> Founda on of neutrinodriven mechanism* Observed energy(an electron neutrino) x 6titiFIG.
2. Contours
Jegerlehner
et ofal. constant1996 likelihood which correspond to3%, 90%, and 95.4% confidence regions, and best-fit values forAssignment 4Kamiokande detected 11 neutrino events from SN 1987A.
By this fact, es mate total neutrino energythat SN 1987A released- You can assume the same numbers for all the avors (6 avors).
- protons in water are main reactor (Cross sec on σ ~ 10-41 cm2 )- E ec ve volume of Kamiokande 2 kton
- Distance to the LMC is 50 kpc+flfltititiff⌫¯e + p ! e + n

レポート課題 4
カミオカンデで11イベントのニュートリノが観測された。
このことから、SN 1987Aがニュートリノとして放出した総エネルギーを概算せよ* すべてのフレーバーのニュートリノが同数放出されたと仮定して良い* 主な反応は水分子中の陽子 (反応断面積σ ~ 10-41 cm2 )* カミオカンデの有効体積 2 kton
* 大マゼラン雲までの距離 50 kpc+⌫¯e + p ! e + nSummary: Core-collapse supernovae• Core-collapse• Triggered by electron capture and photo dissocia on• Explosion mechanism=> Bounce => Shock stalled• Core-collapse=> neutrino hea ng• Neutrino detec on from SN 1987A• Detailed mechanism is not yet solvedtitititi• Explosive nucleosynthesis• 56Ni => hea ng source of supernova

Thermodynamics

Electromagne smClassicalmechanics

Sta s calmechanics

Astrophysics
Hydrodynamics

titititi

Rela vity

Quantummechanics
Nuclear physics

Appendix

Timescales of core-collapse supernovae

Core-collapse~0.1 sec

BounceShock revival~0.1-1 sec

Shock breakoutt(breakout) = R(RSG)/v(SN)~ 1014/109 ~ 105 sec~ 1 dayBreakout~1 day (~105 sec)

R(RSG) ~ 1000 Rsun
~ 1014 cmv(SN) ~ 10,000 km/s
(109 cm/s)

Mass fraction log10(x)u. Rev. Astron. Astrophys. 2013.51:457-509. Downloaded from wwby Kokuritsu-Tenmondai Libr. - National Observatory of Japan on

Beforec0–656Ni

54Fe

116O

24He

34

1H24Mg

228Si

–4
40Ca

56Mr (M )Nomoto+13

Mass fraction log10(x)1Hd56Ni

04He

16O

1H24Mg

2Central remnant

A er

28Si

–4
40Ca

54Fe

56–6123456Mr (M )ftNomoto+13