Nozomu Tominaga

(NAOJ Konan Univ.)

16th Jan 2009 Tsukuba University

Introduction

Past studies

Ongoing projects & discussion First star

SN properties in the early universe

SNe in the distant universe

ReferencesNT et al. 2007 ApJ 657 L77NT, Umeda, & Nomoto 2007 ApJ 660 516NT 2009 ApJ 690 526

SN1987A

BrightL~1042erg/s~109L

8

Energy sourceShock heating

56Ni-56Co decayM(56Ni)~0.07M

8

Energetic

EK~1051erg

Gravitational energyGM

8/RNS~1053erg

Core collapse driven by

Fe photodisociation

NS/BH formation

Energy deposition

H

He

C

O

Si

Massive Star (>10M8

)e--capture SNe (8-10M

8)

Fe

Temp

[108K]

0.2

1.5

7

15

30

40

50

Burning

Stage

H

He

C

Ne

O

Si

NSE

Products

He

C,O

Ne,Mg

O,Mg

Si

Cr,Mn56

Ni

NS/BH

Post-shock Temperature

T∝R-3/4E1/4

56Ni(Fe)

R

Complete Si burning

Fe,α,Ni,Zn,Co,V

Incomplete Si burning

Fe,Si,Cr,Mn

O burning

Si

T [109K]

5

4

3

Shock Propagation

Heavier elements (e.g.,56Ni)

are synthesized in the higher T

layers, i.e., in the inner layers.

faint SNefaint SNe

HypernovaeHypernovae

normal SN

normal SN

Properties of present SNe are derived from

the photometric and spectroscopic observations.

NT + 07; Tanaka, NT, + 08

H, He

Star formation SNeH, He, Z

Metal enrichment

Metallicity increases with time,thus metallicity is a time indicator in the mixed universe.

[Fe/H]= log(Fe/H)-log(Fe/H)8

[Fe/H]0-5 -4 -2

SunMetal-poor starsEarly universe

r-process process

(e.g., Cayrel + 04; Honda + 04)

Unmixed

A few SNe contributed to the EMP stars(e.g., Tumlinson 06)

Note: since the universe was

unmixed, metallicity is NOT a

direct time indicator at [Fe/H]<-2.5.

(1) For lower [Fe/H],higher [Zn/Fe]

UMP

HMP

EMP

CEMP

[Fe/H]<-5Hyper Metal-Poor (HMP)[Fe/H]<-4Ultra Metal-Poor (UMP)[Fe/H]<-3Extremely Metal-Poor (EMP)[Fe/H]<-2Very Metal-poor (VMP)

VMP

(Beers & Christlieb 05)

(2) For lower [Fe/H],higher [C/Fe]

~

The variations (1) and (2) will be explained by the SN variations in the early universe.

(e.g., Cioffi et al. 1988)

The star formation is triggered by the SN shock compression.

The star is made from the mixture of the matter ejected by the SN

(Fe, C, O, etc.)and

swept-up by the shockwave (H, He).

If ISM is metal-free, all metals in the next-generation stars are synthesized and

ejected by the parent SN.

Fe, C, O,

Mg, Si, Ca

H, He

8

A/Blog(B))B(

(A)(A)log[A/B]

swej

swej

MM

MM

Even if ISM is not metal-free, if metal-poor ([Fe/H]<-3), the stars are dominantly contributed by nucleosynthesis in an adjacent SN.

Mej(X): the ejected mass of an element XMsw(X): the swept-up mass of X (=XISM(X) x Msw)

In spherical symmetry (e.g., Thronton + 98),

Hence, Msw(H,He)>>Mej(H,He).

For low metallicity (Mej(metal)>>Msw(metal)),

[A/H]~log(Mej(A)/Msw(H))+con. [A/B]~log(Mej(A)/Mej(B))+con.

If ISM includes metals,

24.037/6514

sw cm1/erg10/1023.5 nEMM

8

Since X(Fe)8

~10-3 and Mej(Fe)~0.07M8/SN, Msw(Fe)=Mej(Fe) if Z=10-3Z

8.

faint SNefaint SNe

HypernovaeHypernovae

normal SN

normal SN

Hypernovae: Mms>25M8, E>1052ergs, M(56Ni)~0.1-0.6M

8

Normal SNe: Mms<25M8, E~1051ergs, M(56Ni)~0.07M

8

Faint SNe: Mms>20M8, E<1051ergs, M(56Ni)~0.001-0.01M

8

24.037/6514

sw cm1/erg10/1023.5 nEMM

8

(Thronton + 98)

(PISNe: E~10-80x1051ergs, M(Fe)~1-30M8)

Hypernovae: E>1052ergs, M(Fe)~0.1-0.6M8

Normal SNe: E~1051ergs, M(Fe)~0.07M8

Faint SNe: E<1051ergs, M(Fe)~0.001-0.01M8

Typical [Fe/H] of the next-generation stars

(PISNe) > Normal SNe > Hypernovae ~ Faint SNe(~-1) VMP EMP CEMP

The variations of SNe lead variations of

not only the abundance ratios [X/Fe] but also [Fe/H].

faint SNefaint SNe

Hypernovae Hypernovae

Mms/M813 15 18 20 25 30 40 50

E/1051erg 1 1 1 10 5,10 20 30 40

M(Fe)/M8

0.07 0.07 0.07 0.08 0.1 0.2 0.3 0.6

ObservationsNormal SNe

13, 15, 18M8

HNe, [O/Fe]=0.520, 25, 30, 40, 50M

8

HNe, [Mg/Fe]=0.230, 40, 50M

8

IMF int. (Salpeter)

[Zn/Fe]↗for [Fe/H]↘

×

13,15,18,20,25,30,40,50M8

IMF

E↗: M(H)↗⇒[Fe/H]↘T↗⇒[Zn/Fe]↗

Variations of Mms and E of CCSNe reproduce the trends of [X/Fe] vs.

[Fe/H] in the EMP stars.

NT, Umeda, Nomoto 07

Ultra metal-poor(UMP)

Hyper metal-poor(HMP)

Extremely metal-poor (EMP)

C-enhanced EMP (CEMP)

(e.g., Cayrel + 04; Honda + 04; Christlieb +02;

Frebel +05; Norris + 07)Metal-poor stars tend to have

high [C/Fe] for low [Fe/H].

What realizes C-rich environments?(They are CEMP-no stars.)

If metal line cooling is a dominant cooling mechanism, to form stars with ~1M

8(Frebel + 07),

Note, dust cooling is also suggested for the cooling mechanism (e.g. Schneider + 2006).

Critical metallicity

Jet

BH/NS BH

Jet

Edep[erg/s]: Energy deposition rate

.parameter

(NT et al. 07, NT 09)

Nucleosynthesis in jet-induced SNe is investigated with special relativistic hydrodynamical calculations.

Jet injection is assumed.

⇔ Diversity of GRB luminosities

Edep=120x1051erg/s

Accreted

Accreted

For lower Edep, the accretion is enhanced, M(Fe) is smaller, and [C/Fe] is higher..

.

O/C

He

Si

Fe

He

H

O/C

H

Edep=1.5x1051erg/s.

In the progenitor

CEMP stars(Depagne + 02)

Edep=3x1051erg/s

M(56Ni)~8x10-4M8

EMP stars(Cayrel +04)

Edep=30x1051erg/s

M(56Ni)~0.1M8

.

.

.

HMP stars(Christlieb + 02; Frebel + 05)

Edep=0.5,1.5x1051erg/s

M(56Ni)~3,4x10-6M8

The variations of the metal-poor stars reflect those of E, Mms, and Edep of CCSNe.

EMP, CEMP, (UMP), HMP starsJet-induced SNe with various Edep

HMP

CEMP

EMP

UMP

EMP starsSNe with various E and Mms

.

Edep

.

E & Mms

.

For high Edep

.

(NT+07a;NT09)

(NT+07b)

Characteristic nucleosynthesis

But there are no evidences.

Stellar lives depend on their masses.

140M8

300M8

10M8

Pair-instability SNeCore-collapse SNe Core-collapse (SNe)

Cosmological structure formation calculations(e.g., Yoshida + 07)

100M8

Present SNe

Were there no PISNe?→ All first stars were >300M

8?

Are not past surveys enough?→ Where do the evidences remain?

M(Fe)~10M8

: if it mixes into M(H)~105M8

, [Fe/H]~-1.

explains the abundance

patterns of the EMP stars.

Metal-poor stars are taken from SAGA database (Suda + 08) which collects >1400 stars from >130 papers. http://saga.sci.hokudai.ac.jp/wiki/doku.php

PISN

PISN

The number of stars with detailed abundances

is expected to increase dramatically.

2007: SEGUE (Sloan Digital Sky Survey)

2009: Skymapper (Australian National University)

Planning: WFMOS (SUBARU/Gemini)

HK survey: ~10,000 MP candidates

Hamburg/ESO survey: ~10,000 MP candidates

SDSS/SEGUE: ~100,000 candidates

WFMOS: they said that abundances of 106(!) stars are

determined. If the fraction of PISN-contributed stars is

> 0.0001%, we may observe them.

Salvadori + 07

Variations of metal-poor stars with [Fe/H]<-2.5

can explain by the SN variations of

energy deposition rates, and

main-sequence masses and explosion energies.

Ongoing projects

Future survey might clarify the existence of PISNe and will

constrain the SN properties statistically.

We will acquire another constraint on SNe.

Shock breakout of distant SNe can be observed by a

photometric deep survey. However, unfortunately we cannot

observe shock breakout of Pop III stars being too faint and

too blue.