Transcript Frank Timmes (ASU)

Sumner Starrfield
School of Earth and Space Exploration
ASU
With a lot of help from my friends:
Theory:
Frank Timmes (ASU)
Dave Arnett (UA)
Raph Hix (ORNL)
Christian Iliadis (UNC)
Observations:
Stella Kafka (AIP)
Jan-Uwe Ness (ESA)
Greg Schwarz (AAS)
Steve Shore (Pisa)
Mark Wagner (LBTO)
(No Postdoc or Graduate student was harmed in the production of this talk)
Why Novae and Nuclear Physics?
1. Largest hydrogen (fusion) bomb in the universe
2. Temperatures in the TNR sample regimes where cross
sections can be directly measured in the lab
3. Result of accretion onto white dwarfs
4. White Dwarf Core material is mixed with accreted
material and ejected and our studies show:
5. Core composition of white dwarf is: CO or ONe
6. Analyses of the ejected gases show non-solar
abundances of ALL elements
7. Possible galactic contributor of:
7Li, 13C, 15N, 26Al (controversial)
8. Ejecta abundances depend strongly on nuclear physics
Sumnery of Unsolved problems:
1.
2.
3.
4.
5.
6.
7.
Latest results from Fermi/LAT: 2/12 CNe emit > 100MeV photons.
Are Classical, Recurrent, and Symbiotic Novae SN Ia progenitors?
When does the mixing occur during the TNR? How much?
How much mass is accreted and ejected during the CN outburst
Are the WDs growing in mass?
How well do we know the ejecta abundances (and mass)?
CV white dwarfs are growing in mass and do not show evidence of
mixing
8. So, Is there any way to prevent the mixing?
9. And, if so, are Cataclysmic Variables Ia progenitors [not CNe]?
10.What is the mass of the White Dwarf?
11.What is the evolutionary status of the secondary (mass donor)?
12.What are the effects of magnetic fields on the WD and on the
secondary?
Latest Observational Results for SN Ia progenitors: Single Degenerate Scenario:
1. SN Ia 2011fe (M101) discovered by the Palomar Transient Factory about 11 hours after the
explosion. No evidence for circumbinary material and progenitor likely a CO WD.
2. However, PTF 11kx was a SN Ia that exploded in a system with circumbinary material and
they suggest that the progenitor was a Symbiotic Binary like RS Oph. But maybe not.
3. LMC: Schaefer and Pagnotta (2012) did not “find” a star in the “center” of a Ia remnant in
the LMC (to stringent but not impossible limits); Edwards, Pagnotta , Schaefer (2012) find
lots of stars in the center of another SN Ia remnant.
4. Zorotovic et al. (2011) find that the WDs in Cataclysmic Variables are growing in mass.
5. For example: U Gem –1.2M; SS Cyg – 0.8M ; IP Peg – 1.16M; Z Cam – 0.99M
These are the nearest and brightest CV’s. [Canonical value is 0.6M for single WDs]
“Conclusions”
1. SN Ia’s are a mixed zoo but they can “diddle” the data to make them standard candles.
2. The Single Degenerate scenario is not ruled out.
3. Something is preventing mixing in CV’s as opposed to Classical Novae where the mixing
must be taking place.
Large Area Telescope on FERMI
Pair Conversion 30 times more sensitive than EGRET on Compton
Has now detected V407 Cyg (external shocks), Nova Sco 2012 and
Nova Mon 2012 at E > 100 MeV (cause unknown)
2 out of 12 during Fermi’s lifetime
A nova ejects ~10 to 100 Earth
masses (1028 gm to 1029 gm)
at speeds from
300 km/sec to 7000 km/sec
GK Per (1901)
V1974 Cyg (1992)
DQ Her (1934)
V445 Puppis - Discovered in 2000 - imaged with Active Optics
No Hydrogen detected in the ejecta - mostly helium and carbon
White Dwarf accreting from a Hydrogen Deficient Carbon star
Nova V838 Her
1991: Never
showed the
oxygen
forbidden lines
at 4959Å and
5007Å implying
that oxygen was
under abundant
in the ejecta.
The presence of
the sulfur lines
implied that
sulfur was
enriched
These two
novae are
nearly
identical in
ejecta
abundances
but
occurred in
two
different
galaxies
Log Abundance / Abundance of H
Ejecta Abundances for Three Novae:
Breakout: 15O(,)19Ne may have occurred
He
C
N
O
Ne
Vanlandingham et al.
Mg
Al
Si
S
How Does the Mixing Occur?
Chemical Diffusion
Occurs Early in accretion and is too slow.
Insufficient amount of mixing
Shear Mixing During Accretion
Occurs Early in Accretion Phase
Multidimensional Studies in Progress
Convective “Undershooting”
Multidimensional Studies by:
–Glasner, Livne, Truran
–Kercek, Hillebrandt, Truran
–Glasner and Truran
–Casanova, Jose, Shore, Calder
More Work Required (IN PROGRESS)
What might Prevent it in CV’s ?
PROBLEM
Novae are
observed
to eject
more mass
than theory
predicts
can be
accreted
onto the
white
dwarf
There are novae both in our galaxy and in the LMC that have
extremely similar ejecta abundances and so the WD mass
and composition are also probably similar
V838 Her 1991 was an ONe novae where Oxygen was
depleted and Sulfur was enriched.
Hydrodynamic evolutionary simulations done with the Arnett
and Truran Carbon burning abundances seem to require
breakout to reach sulfur.
Simulations done with the Ritossa et al. abundances do
produce sulfur with no breakout. Further work is in progress
Nuclear Thermometers
For
Classical Novae
Lori Downen
Christian Iliadis
Jordi Jose
Sumner Starrfield
ApJ
(Almost in press)
Elemental ratios with steep
temperature dependencies on
Peak temperature determined from
Post processing of the
Jordi Jose
Temperature-density – time
Trajectories
WD Mass
M
T(Peak)
GK
1.15
1.25
1.30
1.35
.228
.248
.265
.313
[Starrfield et al. 2009: 1.25M
1.35M
Peak Temperature (GK)
.32
.39
What is the evidence that
Novae ejected gases
reached
and were inserted into the
forming
Solar System?
Interplanetary Dust Particles (IDPs) collected
from
Comets Grigg-Skjellerup And Tempel-Tuttle
Conclusions:
There are no solved problems
CONCLUSIONS
A nova explosion is the result of accretion of H-rich
material onto a white dwarf.
There are TWO classes of nova:
carbon - oxygen
oxygen - neon- magnesium
The explosion is powered by radioactive decays of the
positron-decay nuclei.
New reaction rates, opacities, and core abundances are
changing the predictions.
The abundance of 26Al is sufficiently large that Novae
may be one of the Galactic sources of 26Al
The predicted abundance of 22Na is sufficiently large for
its decay to be observed in nearby novae.