A presentation on the first cosmic explosions and how the Universe started to make heavy elements, by Monash University's Professor Alexander Heger from the Faculty of Science, School of Mathematical Science.

1. The Star's Brain
55,500 MꙨ Star exploding at 1055 erg (Ken Chen 2011)

2. Astronomical Society of Victoria, Monash University, Australia, Feb. 13, 2013
Supernovae and the
First Stars in the
Universe
The first cosmic explosions and how the Universe
started to make heavy elements
http://CosmicExplosions.org
Alexander Heger (Monash)
Ken Chen (UMN)
Pamela Vo (UMN)
Candace Joggerst (LANL)
Stan Woosley (UCSC)

3. Motivation:
A Brief History
of the Universe

4. The Cosmic Dark Age
`
(after recombination)

7. What the
Big Bang
made…
(The primordial abundance pattern)
Brian Fields (2002, priv. com.)

8. What We
Find Today
(The solar abundance pattern)
Lodders (2003)

10. Cosmic Dark Age
`
(after recombination)
© Alexander Heger Hubble Deep Field
time
What the (Pop III star yields) What We
Heger & Woosley (2010)
Big Bang Frebel et al. (2005) Find Today
made…
(The primordial abundance pattern) (The solar abundance pattern)
Brian Fields (2002, priv. com.) Lodders (2003)

11. Setting the Stage:
Stellar
Evolution

13. 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

14. Ban
g!
Bo
om
!

15. NGC3982

16. Core Collapse Supernovae
(Janka 2001)
(Woosley & Janka 2006)
Entropy and electron
per baryon (Ye) at
different time snapshots
in a core collapse
supernova
(simulation: equatorial band)
(Buras et al. 2006)

17. Core Collapse Supernovae – 3D
Cold inflow and hot outflow
in 3D simulations  similar to dipolar
flow pattern observed in 2D rotationally
symmetric simulations
(Janka et al. 2005)
(Scheck, Janka, et al. 2006)

18. Singing Supernovae?
Can sound waves from convection heat bubble and
Stan
Woosley
power a supernova explosion?
(Burrows et al. 2005)
(Burrows et al. 2005) (Burrows et al. 2005)
radius (km)
radius (km)

19. 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
Mueller, Janka, Heger (2012)
u8.1

20. The First
Stars
in the Universe

21. Formation and Mass
of the First Stars
after recombination
No 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 ... (Turk, Abel, O'Shea 2010)
We still don't have a really strong constrain on
Pop III star masses in general

22. credit: Matt Turk

23. Were the first stars really big?
How do we know?
?
&Spitzer=0.00&ChandraXO=0.00&Galex=0.00&IRAS=0.00&WMAP=0.00&Cassini=0.00&slid

24. The
proof:
It is on
Google
Sky!
=-87.1875&zoom=2&Spitzer=0.00&ChandraXO=0.00&Galex=0.00&IRAS=0.00&WMAP=0.0

25. Eta Car – a really big star in our galaxy today

26. The Most Massive Stars Today
R136
● young massive star
cluster
● Age around 1.5 Myr
● Star “a1”:
maybe 200 MꙨ
initial mass
(Crother et al. 2010)

27. Ejected “metals”

28. How Bigger Stars Die:
Pair-Instability
Supernovae

29. approximate
Fe-poor Fe-rich
explosion energy / B
pl
E ex

30. •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

31. Problem
Pair-Instability Supernovae do
not reproduce the
abundances as observed in
very metal poor halo stars!

32. Mixing in 250 MꙨ Pair-SN
(Ken Chen 2011)

34. Pulsational
Pair-Instablity
Supernovae

35. PPSN in 2D
Ken Chen (2012)

36. PPSN in 2D
Ken Chen (2012)

37. PPSN in 2D
Ken Chen (2012)

38. Energy Scales
Log 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) √