(Ken Chen 2011)

The Star's Brain

55,500 MꙨ Star exploding at 1055 erg

Supernovae and the First Stars in the

UniverseThe first cosmic explosions and how the Universe

started to make heavy elements

Alexander Heger (Monash)Ken Chen (UMN)

Pamela Vo (UMN)

Candace Joggerst (LANL)

Stan Woosley (UCSC)

http

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Astronomical Society of Victoria, Monash University, Australia, Feb. 13, 2013

Motivation:

A Brief History of the Universe

`

The Cosmic Dark Age

(after recombination)

(The primordial abundance pattern)Brian Fields (2002, priv. com.)

What the Big Bangmade…

(The solar abundance pattern)Lodders (2003)

What We Find Today

`

Cosmic Dark Age

(after recombination)

time

What WeFind Today

What theBig Bang

made…

(The primordial abundance pattern)Brian Fields (2002, priv. com.)

(The solar abundance pattern)Lodders (2003)

(Pop III star yields)Heger & Woosley (2010)

Frebel et al. (2005)

© Alexander Heger Hubble Deep Field

Setting the Stage:

StellarEvolution

Once formed, the evolution of a star is governed by gravity: continuing contraction

to higher central densities and temperatures

Evolution of central density and temperature of 15 MꙨ

and 25 MꙨ stars

Boom!

Bang!

NG

C3

982

(Janka 2001)(Woosley & Janka 2006)

(Buras et al. 2006)

Core Collapse Supernovae

Entropy and electron per baryon (Ye) at different time snapshots in a core collapse supernova (simulation: equatorial band)

(Janka et al. 2005)

Core Collapse Supernovae – 3D

(Scheck, Janka, et al. 2006)

Cold inflow and hot outflow in 3D simulations similar to dipolar flow pattern observed in 2D rotationally symmetric simulations

Singing Supernovae?

rad

ius

(km

)

rad

ius

(km

)

(Burrows et al. 2005)

(Burrows et al. 2005) (Burrows et al. 2005)

Can sound waves from convection heat bubble andpower a supernova explosion?

Stan Woosley

u8.1Mueller, Janka, Heger (2012)

Explosion of Low-Mass SN

2D simulation with neutrino transport and core cooling

Explosion driven by convection not SASI

Explosion starts fast as accretion drops very rapidly

The First Stars

in the Universe

Formation and Mass of the First Stars

after recombinationNo metals no metal cooling more massive stars

(Bromm, Coppi, & Larson 1999, 2002; Abel, Bryan, & Norman 2000, 2002;Nakamura & Umemura 2001; O’Shea & Norman 2006,...)

typical mass scale ~10...300 MꙨ?

• Now simulations indicate binaries may exist

• But ...We still don't have a really strong constrain on Pop III star masses in general

(Turk, Abel, O'Shea 2010)

credit: Matt Turk

http://maps.google.com/sky/#latitude=-7.01366792756663&longitude=-87.1875&zoom=2&Spitzer=0.00&ChandraXO=0.00&Galex=0.00&IRAS=0.00&WMAP=0.00&Cassini=0.00&slide=1&mI=-1&oI=-1

Were the first stars really big?

How do we know?

?

http://maps.google.com/sky/#latitude=-7.01366792756663&longitude=-87.1875&zoom=2&Spitzer=0.00&ChandraXO=0.00&Galex=0.00&IRAS=0.00&WMAP=0.00&Cassini=0.00&slide=1&mI=-1&oI=-1

The proof:

It is on Google Sky!

Eta Car – a really big star in our galaxy today

The Most Massive Stars Today

R136● young massive star cluster

● Age around 1.5 Myr

● Star “a1”:maybe 200 M

Ꙩ

initial mass

(Crother et al. 2010)

Eje

cted

“m

etal

s”

How Bigger Stars Die:

Pair-InstabilitySupernovae

expl

osio

n en

ergy

/ B

approximate

E expl

Fe-richFe-poor

•Low neutron excess from CNO -> 22Ne in helium burning

•No extended stable period of carbon and oxygen burning where weak interactions might increase the neutron excess

ProblemPair-Instability Supernovae do

not reproduce the abundances as observed in very metal poor halo stars!

(Ken Chen 2011)

Mixing in 250 MꙨ Pair-SN

Pulsational Pair-Instablity

Supernovae

PPSN in 2D

Ken Chen (2012)

Ken Chen (2012)

PPSN in 2D

Ken Chen (2012)

PPSN in 2D

Energy ScalesLog E Explosion Thermonuclear

39 X-ray Bursts √

40 Long-Duration He Bursts √

41

42 X-ray Superbursts √

43

44

45 Classical Novae √

46

48 Faint SN (visible LC?)

49 SN (visible LC)

50 Bright SN (LC?)

51 SN (kinetic) SN Type Ia total

52 Hypernova? GRB? Pair-SN total (low-mass end)

53 SN (neutrinos – several 1053erg) Pair-SN total (upper limit)

54 (a lot of energy - 0.5 MꙨ c2)

55 GR He SN GR He SN (upper limit)

56 GR H SN, Z > 0 (Fuller et al. 1986) √