Stellar fireworks and the origin of the elements

Thanassis Psaltis (@psaltistha)
TU Darmstadt, Institut für Kernphysik Theoriezentrum
 

December 8, 2022
Nuclear Lunch • University of Athens


 

Image Credit: NASA/CXC/DSS/Rutgers/K.Eriksen et al.
Slides available at http://psaltisa.github.io/talks

Acknowledgements

Alan Chen   Almudena Arcones   Melina Avila   Barry Davids   Camilla Juul Hansen   Annika Lennarz   Richard Longland   Peter Mohr   Fernando Montes   Chris Ruiz

+ many graduate students!

How I see nuclear astrophysics

How were the elements from iron to uranium made?

How I see nuclear astrophysics

Nuclear reaction networks

are an essential tool for Nuclear Astrophysics

W. R. Hix and F.-K. Thielemann, J. Comput. Appl. Math 109, 321 (1999)
C. Jiang et al., New J. Phys. 23 083035 (2021)

How do we identify
important reactions?

Sensitivity studies guide our way

Same model, but different nuclear input!

S. Wanajo et al., Astrophys. J 729, 46 (2011)

Why study the $\mathrm{^7Be(\alpha,\gamma)^{11}C}$ reaction?

  • Affects the number of $\mathrm{^{56}Ni}$ during the $\nu p$-process, and the production of $A \sim 100-110$ neutron-deficient species.
    S. Wanajo, H.-T. Janka and S. Kubono, Astrophys. J. 729, 46 (2011)

  • Its rate is not well known over the relevant energy region.
    Only 2 measured resonances (NACRE-II).
    Y. Hu et al. Nucl. Phys. A 918, 61 (2013) • G. Hardie et al., Phys. Rev. C 29, 1199 (1984)
    M. Wiescher et al., Phys. Rev. C 28, 1431 (1983) • H. Yamaguchi et al., Phys. Rev. C 87, 034303 (2013)

Constrain the reaction rate for $\mathrm{^7Be(\alpha,\gamma)^{11}C}$ at $\nu p$-process temperatures

How to measure the $\mathrm{^7Be(\alpha,\gamma)^{11}C}$
reaction in a lab

C.R. Brune and B. Davids, Annu. Rev. Nucl. Part. 65, 87 (2015) • C. Rolfs and C.A. Barnes, Annu. Rev. Nucl. Part. 40, 45 (1990)

The DRAGON recoil separator 🐲

D.A. Hutcheon et al., Nucl. Instr. Meth. Res. A 498, 190 (2003)

Reactions in inverse kinematics

DRAGON's acceptance $ -~\mathrm{\theta_{DRAGON} \sim 21~mrad}$

$\mathrm{^7Be(\alpha,\gamma)^{11}C - \theta_{r,max} \sim 43~mrad}$

C. Ruiz, U. Greife and U. Hager, Eur. Phys. J. A 50, 99 (2014)

Can DRAGON can measure $\omega \gamma$ of reactions
with $\mathrm{\theta_{r,max}>\theta_{DRAGON}}$ ?



Proof-of-principle test: $\mathrm{^6Li(\alpha,\gamma)^{10}B}$
A. Psaltis et al., Nucl. Instrum. Methods Phys. Res. A 987, 164828 (2021)

DRAGON can measure $\omega \gamma$ of reactions with $\mathrm{\theta_{r,max}>\theta_{DRAGON}}$

$\mathrm{\omega \gamma_{lit}= (0.228 \pm 0.038)~eV}$
$\mathrm{\omega \gamma_{DRA}= 0.225^{+0.025}_{-0.035} (stat.) \pm 0.030 (syst.)~eV}$

A. Psaltis et al., Nucl. Instrum. Methods Phys. Res. A 987, 164828 (2021)

Measure the $\mathrm{^7Be(\alpha,\gamma)^{11}C}$ reaction

The DRAGON recoil separator 🐲

D.A. Hutcheon et al., Nucl. Instr. Meth. Res. A 498, 190 (2003)

$\mathrm{^7Be(\alpha,\gamma)^{11}C}$ PID plot

A. Psaltis et al., Phys. Rev. C 106, 045805 (2022)

$\mathrm{^7Be(\alpha,\gamma)^{11}C}$ BGO plot

A. Psaltis et al., Phys. Rev. Lett. 129, 162701 (2022)

$\mathrm{^7Be(\alpha,\gamma)^{11}C}$ resonance strength results

A. Psaltis et al., Phys. Rev. Lett. 129, 162701 (2022) • A. Psaltis et al. Phys. Rev. C 106, 045805 (2022)

The new $\mathrm{^7Be(\alpha,\gamma)^{11}C}$ reaction rate

We decreased the rate uncertainty to $\approx 10\%$ over $T= 1.5-3$ GK

Take-home message #1


We measured the $\mathrm{^7Be(\alpha,\gamma)^{11}C}$ reaction using DRAGON and constrained its rate over $\nu p$-process energies.

How I see nuclear astrophysics


 

 

 

 

 

 

 
HD 122563 (DSS2/ Aladin Sky Atlas)

What do the old stars reveal to us?

See also: C. Sneden, J. J. Cowan and R. Gallino, Annu. Rev. Astron. Astrophys. 46, 241 (2008)

How many processes contribute to the production of elements between Sr and Ag?

What is the impact of the
$\mathbf{(\alpha,xn)}$ reactions
in the weak $r$-process?

How I see nuclear astrophysics

How well do we know the $(\alpha,xn)$ reaction rates?

The $(\alpha,xn)$ reaction rates are sensitive to the $\alpha$-optical model potential and can differ by up to two orders of magnitude.

J. Pereira and F. Montes, Phys. Rev. C 93, 034611 (2016) • P. Mohr, Phys. Rev. C 94, 35801 (2016)

How I see nuclear astrophysics

The impact of new $(\alpha,n)$ reaction rates to
elemental abundances

Same model, but different $(\alpha, xn)$ reaction rates!

A. Psaltis et al., Astrophys. J 935, 27 (2022)

The impact of new $(\alpha,n)$ reaction rates
to elemental abundance ratios

A. Psaltis et al., Astrophys. J 935, 27 (2022)

Combine observations, astrophysical modeling and nuclear physics uncertainties

A. Psaltis et al., Astrophys. J 935, 27 (2022)

Which are the most important
$\mathbf{(\alpha,xn)}$ reactions
for the weak $r$-process?

Finding the most important $(\alpha,n)$ reactions
for the weak $r$-process

The most important $(\alpha,n)$ reactions
for the weak $r$-process

  1. $\mathrm{^{84}Se}$, $\mathrm{^{87-89}Kr, ^{93}Sr}$
    Affect many elemental ratios in many astrophysical conditions

  2. $\mathrm{^{86}Br,^{86, 90}Kr, ^{87-89}Rb, ^{91, 92, 94}Sr, ^{94}Y}$
    Affect few elemental ratios in many astrophysical conditions

  3. $\mathrm{^{85}Se, ^{85}Br}$
    Affect many elemental ratios in few astrophysical conditions

  4. $\mathrm{^{63}Co, ^{67}Cu, ^{79, 81}Ga, ^{76}Zn, ^{80, 82}Ge, ^{83}As}$
    $\mathrm{^{87, 90, 91}Rb, ^{88-90}Sr, ^{95, 96}Y, ^{96-98}Zr}$
    Affect few elemental ratios in few astrophysical conditions

Take-home message #2


We combined observations, astrophysical modeling and nuclear theory
to study the impact of $(\alpha,xn)$ reactions to the weak $r$-process

Can we study these $\mathbf{(\alpha,xn)}$ reactions in the lab?

First measurement of the $\boldsymbol{\mathrm{^{93}Sr}(\alpha,xn)\mathrm{^{96-x}Zr}}$ reaction

$\mathrm{^{93}Sr}(\alpha,xn)\mathrm{^{96}Zr}$ at Argonne with MUSIC

M. L. Avila et al., Nucl. Instrum. Methods Phys. Res A 859, 63 (2017)

  • Re-accelerated $\mathrm{^{93}Sr}$ beam from $\nu$CARIBU.
  • Close to 100% efficiency due to its segmented anode structure. Self-normalizing, no additional monitor detectors are needed.
  • Measure a large range of excitation functions of angle and energy integrated cross sections using single beam energy
Proposal #1923, PI: Psaltis, co-PI: Ong

Measurement of $\boldsymbol{(\alpha,xn)}$ reactions at FRIB using SECAR

Most of the relevant beams are accessible now!

FRIB PAC2 expected beam rates

The SECAR recoil separator

G. Berg et al., Nucl. Instrum. Methods Phys. Res A 877, 87 (2018)

What we expect in the near future

More observations of old stars and measurements on the key $(\alpha, xn)$ reactions will help us constrain the production site of the elements between Sr and Ag.

Take-home messages

  1. We measured the $\mathrm{^7Be(\alpha,\gamma)^{11}C}$ reaction using DRAGON and constrained its rate over $\nu p$-process energies.

  2. We combined observations, astrophysical modeling and nuclear theory to study the impact of $(\alpha,xn)$ reactions to the weak $r$-process.

  3. Experiments in the current and next-generation facilities, along with multimessenger observations and theoretical modeling will help us better understand the origin of the elements.