# Presentation: 154973

## EVOLUTION OF VERY MASSIVE POPULATION III STARS

**T. Ohkubo, H. Umeda, K. Maeda, K. Nomoto, **
**T. Suzuki, S. Tsuruta, M.J. Rees**

- First Stars III Workshop, July 16-20 2007, Santa Fe, NM, USA

## Supernovae and Chemical evolution of the universe

- Big Bang

- core-collapse SNe (massive)

- type Ia SNe (light)

- O,Mg,Si,Ca

**only  H, He (metal-free)**

- Mn,Fe,Co,Ni

- present

- Sun

- Earth

**Metal?**

**metal-rich universe**

**First Stars**

**?**

**Metal**

**1.37x10****10**
**     ****years**

- I. INTRODUCTION

## II. OUR RECENT RESEARCHOhkubo et al. ApJ, 645, 1352, July 10, 2006 

**Evolution**

**Explosion**

**Nucleosynthesis**

- zero-age main sequence to Fe-core collapse
- (initial model for explosion, UV photon supply)

- hydrodynamical calculation
- 2 dimensional jet like explosion

- comparison with observational abundance pattern

## Evolusionary track 

- central temoperature

- central density

## Explosion

- dEjet/dt =  (dMacc/dt) c2

- jet: jet angle(15o)

- initial BH mass・・・100M

- :energy transformation efficiency
-    (0.002 – 0.01)

**1000M******** ****model (our result of evolution)**
- Code・・・2D hydrodynamical code including gravity (Maeda & Nomoto 2003)
-               explosion energy source・・・jet injection around BH

- BH
- Jet
- Disk

## Snapshot of explosion (density structure)

- R/R*

## Abundance pattern and comparison with observational data

-  **Compare** **Abundance Pattern by nucleosynthesis with observational data**
- (extremely metal-poor stars, M82 gas, intracluster matter, inter galactic medium)

- black hole mass increases by accretion
- final black hole mass?

**1**

**(****very-massive star formation****)**

**2**

- Link ?

##  Presupernova Composition

-  Presupernova Composition

- p

- He

- Fe

- Si

- O

- Ne

- C

- Mg

- 56Ni

**‘****Fe’**

- p

- He

- 1000M

- For 25M Model, Fe-core is < 10%
- (Umeda & Nomoto 2003)

**Fe-core is >20%**

## Abundance Pattern

**ε=0.0025****、********jet****=15****o**

-   Metal-poor stars ([Fe/H]<-3)
-                     (Cayrel et al. 2004)

- there is discrepancy in [O/Fe]

**[O/Fe] < 0 ,[Si/Fe] >0 : Consistent**

* ****EMP (extremely metal-poor) ***
***stars***

* ****ICM (intracluster matter)***

**ε=0.005****、********jet****=15****o**

## Consistent rather than 25M hypernova model

- Gas composition in M82
- (Origlia et al. 2004)

**・****[O/Fe]~****-****0.3**
**・ ****[Ne/Fe]~0, [Mg/Fe]~ 0.3, [Si/Fe]~ 0.2**
** ****Black hole mass 500M**  ・・・consistent with IMBH mass

-   25M hypernova model
-       Umeda & Nomoto (2002)

**Consistent rather than 25M**** hypernova model**

## IGM (inter galactic medium) (redshift z:2~4.5)

Observation: [C/Si] <~ -0.5  (Aguirre et al. 2004)

Yields by PISNe: [C/Si] ~ -2.0 -- -1.7
Our 1000M yields: [C/Si] ~ -0.78 ---0.65

     Consistent in order of magnitude with observational ratio

**Observation: [C/Si] <~ ****-****0.5**  (Aguirre et al. 2004)
**Yields by PISNe: [C/Si] ****~ -****2.0 -- ****-****1.7**
**Our 1000M******** yields: [C/Si] ~ ****-****0.78 --****-****0.65**
-      **Consistent in order of magnitude with observational ratio**

## UV photon supply

**Log(T****eff****) ~**** ****5.05**
-                   (4.85 – 5.0 for Pop III 15 – 90M stars)
- 		(Tumlinson & Shull 2000)
-      **Ionizing photons (/s/M****)**
**                                 **
**	****	****	****  ****H I**** :  1.6 × 10****48****  (****16 times higher****) **
**                                 ****He I**** : 1.1 × 10****48****  (****14 times higher****)**
**         **
**                                 ****He II****:  3.8× 10****47****  (****75 times higher**** ****)**
**         **
**than by Salpeter IMF** (values with a Salpeter IMF)

## UV photon supply and chemical contamination

- Nreionize / Nb  (Number of UV photon supply 	per baryon) ~150
-          ( >> 10・・・necessary for reionization of IGM at z~4 )
- 			Miralda-Escude&Rees 97

- UV photon supply

- evolving stars

- exploding star

- chemical contamination

## This work

- normal SN

- Hypernova

- PISN

**this work**

- Initial Mass

- Energy (erg)

- 10

- 100

- 1000

- 1051

- 1052

- 1053

- 1054

- 1055

- 1056

- 300

**1000M******** ****model****・・・****core-collapse very-massive stars**

## III. Summary/CONCLUSION

**(i)**** ****1000M******** stars ****・・・****UV photons efficiently ****	****supplied**** **
**      **
** ****(ii) Final black hole is  ~ 500M******
**     ****・・・****consistent with IMBH mass**
**(iii) Abundance pattern**
**     ****・・・****consistent with M82 gas, ICM, IGM**