First Stars
Project page for the first stars that formed in the universe.
Collaborators
- Alexander Heger
- Stan Woosley
- Conrad Chan
- James Grimmett
- Bernhard Mueller
- Pamela Vo
- Anna Frebel
- Maria Bergemann
- Norbert Christlieb
- Candace Joggerst
- Weiqun Zhang
- Yong-Zhong Qian
- Daniel Holz
- Evan Scannapieco
- Brian O'Shea
- Daniel Whalen
- Isabelle Baraffe
- Tom Abel
Data
Heger & Woosley (2010):
Evolution and Nucleosynthesis of Primordial Stars
StarFit
(tutorial)
Past Conferences
-
Chemical Enrichment of the Early Universe,
August 9 - August 13, 2004,
Santa Fe, New Mexico
-
The First Stars and Evolution of the Early Universe,
June 19 to July 21, 2006,
Institute for Nuclear Theory, University of Washington, Seattle, WA
-
First Stars III,
Jul 16 to 20, 2007,
Santa Fe, NM
Current Projects
Past Projects
Finding the First Cosmic Explosions
(LANL LDRD Project 20080080ER)
- Alexander Heger
- Daniel Holz
- Brian O'Shea
- Daniel Whalen
- Bruce Fryxell
- Candace Church
Coming out of the Cosmic Dark Ages - The First Stars in the Universe
(LANL LDRD Project 20050031DR)
- Alexander Heger
- Hui Li
- Chris Fryer
- Kent Budge
- Shengtai Li
- Stirling Colgate
- Gerry Jungman
- Mike Warren
- Sanjay Reddy
- Joe Carlson
- Aimee Hungerford
- Rob Coker
- Kim New
- Galen Gisler
- Brian O'Shea
- Falk Herwig
- Shannon Cowell
- Nathan Currier
- Dan Whalen
- Andrew Steiner
- Mike Norman
- Pedro Marronetti
Publications (not current)
-
The Beginning of Stellar Nucleosynthesis
by
A. Heger &
S. E. Woosley
(2002, to appear in proceedings of the 11th Workshop on Nuclear
Astrophysics, Ringberg Castle, eds. E. Müller and
W. Hillebrandt, MPA Proceedings, Garching)
-
Evolution and Explosion of Very Massive Primordial Stars
by
A. Heger,
S. E. Woosley,
I. Baraffe, &
T. Abel
(2002, to appear in Proc. Lighthouses in the Universe,
"ESO Astrophysics Symposia", Springer-Verlag)
-
The Nucleosynthetic Signature of Population III
by
A. Heger &
S. E. Woosley
(2002, accepted by ApJ,
astro-ph/0107037;
DATA)
-
On the stability of very massive primordial stars
by
I. Baraffe,
A. Heger, &
S. E. Woosley
(2001, ApJ, 550, 890
astro-ph/0009410)
-
Pair-Instability Supernovae, Gravity Waves, and Gamma-Ray Transients
by
C. L. Fryer,
S. E. Woosley, &
A. Heger,
(2000, ApJ 541, 1033,
astro-ph/0007176)
-
Evolution and Nucleosynthesis of Very Massive Primordial Stars
by
A. Heger,
I. Baraffe,
C. L. Fryer, &
S. E. Woosley
(2001, Nuclei in the Cosmos 2000,
eds. K. Langanke and J. Christensen-Dalsgaard, Amsterdam:
Elsevier; Nuclear Physics A, 688, p. 197c - 200c;
astro-ph/0010206)
-
Evolution and Nucleosynthesis in Massive Stars of Zero Metallicity
by
A. Heger,
S. E. Woosley, &
R. Waters
(2000, in proceedings of the MPA/ESO workshop The first Stars,
eds. A. Weiss, T. Abel, & V. Hill, Berlin: Springer Verlag, p. 121)
Resources
Figure 1:
Initial-final mass function (IFMF) of non-rotating primordial stars (Z
= 0). The x-axis gives the initial stellar mass. The
y-axis gives both the final mass of the collapsed remnant
(thick black curve) and the mass of the star when the event
begins that produces that remnant (e.g., mass loss in AGB stars,
supernova explosion for those stars that make a neutron star, etc.;
thick gray curve). We distinguish four regimes of initial
mass: low mass stars below ~10 M_sun that from white dwarfs;
massive stars between ~10 M_sun and ~100 M_sun; very massive
stars between ~100 M_sun and ~1000 M_sun; and supermassive
stars (arbitrarily) above ~1000 M_sun. Since no mass loss is
expected for Z = 0 stars before the final stage, the grey curve
corresponds approximately to the line of no mass loss (dotted),
except for ~100-140 M_sun where the pulsational pair-instability
ejects the outer layers of the star before it collapses, and above
~500 M_sun where pulsational instabilities in red supergiants may lead
to significant mass loss. Since the magnitude of the latter is
uncertain, lines are dashed. In the low mass regime we assume,
even in Z = 0 stars, that mass loss on the asymptotic giant branch
(AGB) removes the envelope of the star leaving a CO or NeO white dwarf
(though the mechanism and thus the resulting initial-final mass
function may differ from solar composition stars). Massive stars are
defined by stars that ignite carbon and oxygen burning
non-degenerately and do not leave white dwarfs. The hydrogen-rich
envelope and parts of the helium core (dash-double-dotted
curve) are ejected in a supernova explosion. Below initial masses
of ~25 M_sun neutron stars are formed. Above that, black holes form,
either in a delayed manner by fall back of the ejecta, or directly
during iron core collapse (above ~40 M_sun). The defining
characteristic of very massive stars is the electron-positron
pair instability after carbon burning. This begins as a
pulsational instability for helium cores of ~40 M_sun (M_ZAMS = ~100
M_sun; ZAMS = "zero-age main sequence"). As the mass increases, the
pulsations become more violent, ejecting any remaining hydrogen
envelope and an increasing fraction of the helium core itself. An
iron core can still form in hydrostatic equilibrium in such stars, but
it collapses to a black hole. Above a helium core mass, M_He, of ~63
M_sun or about M_ZAMS = 140 M_sun, and on up to M_He = 133 M_sun or
about M_ZAMS = 260 M_sun) a single pulse disrupts the star. Above 260
M_sun, the pair instability in non-rotating stars results in complete
collapse to a black hole.
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Alexander Heger
Sunday, 09-Dec-2018 08:54:46 AEDT
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