Miklós Kiss Berze High School, Gyöngyös, Hungaryparrise.elte.hu/tpi-15/slides/Kiss_Miklos_Nucleosynthesis.pdf · Neutron Capture Nucleosynthesis Kiss Miklós, Berze High School

Neutron Capture Nucleosynthesis Kiss Miklós, Berze High School Gyöngyös Teaching Physics Innovatively ELTE, 2015.08.17-19. 1

Neutron Capture Nucleosynthesis

Miklós Kiss

Berze High School, Gyöngyös, Hungary

Teaching Physics Innovatively

ELTE, 2015.08.17-19.


Contents

1. The Chart of nuclei

2. Neutron sources

3. The neutron capture processes

4. Competition, lifetime

5. s-process – r-process

6. The neutron

7. Our model

8. Input data

9.1 Example 1: classical s-process

9.2 Example 2: r-process

9.3 Example 3: r-process

9.4 Example 4: m-process

10. Termination of s-process?

11. The role of base time, the width of

the band

12. The role of base time, the profile

of the band

13 The role of neutron density, the

profile of the band

14. Experiences and conclusion

15. Tellurium I.

16. Tellurium II.

17. Criteria

18. Rate Analysis or a Possible

Interpretation of Abundances

19. Isotopic case

20. Isotonic case

21. What neutron density is required?

22. Final conclusions

23. References


1. The Chart of Nuclei

[Chart of Nuclides (NuDat2) National Nuclear Data Center www.nndc.bnl.gov/nudat2, Brookhaven National Laboratory]

How nuclei are formed beyond iron?


2. Neutron sources The two main processes:

and

The first process occurs in massive helium burning stars and in AGB TP, the second

occurs in AGB stars at the TDU following the TP


3. The neutron capture processes

Neutron capture

Beta decay after

neutron capture

Gamow 1948, B2FH = Burbidge, Burbidge, Fowler és Hoyle 1957


4. Competition, lifetime

Lifetime of unstable nuclei:

Time between two neutron captures:


5. s-process – r-process

data

nuclei formation in the valley of

beta stability

nuclei formation far from the

valley


6. The neutron

Half-time: 10.4 min (611±1 s)

(Average) lifetime: 15 min (881.5±1.5 s)

[K. Nakamura et al. (Particle Data Group), JP G 37, 075021 (2010) and 2011 partial update for the 2012 edition

(URL: http://pdg.lbl.gov)]

Classical:

Into the s-process we must involve the nuclei if the lifetime greater than ten years.

Question:

Does the neutron take part in the neutron capture process?


7. Our model

There are no previously

excluded nuclei.

All nuclei are involved.

The exclusion made by

model.

We must take into account

all data of all nuclei.


8. Input data data of 2696 nuclei (stable 178, unstable 2518)

at r-process: 5353 nuclei

half-times, decay modes, decay ratio,

neutron capture cross sections

MACS http://adg.llnl.gov/Research/RRSN/semr/30kev/rath00_7.4.30kev_calchttp://adg.llnl.gov/Research/RRSN/semr/30kev/rath00_7.4.30kev_calchttp://adg.llnl.gov/Research/RRSN/semr/30kev/rath00_7.4.30kev_calchttp://adg.llnl.gov/Research/RRSN/semr/30kev/rath00_7.4.30kev_calc


9.1 Example 1: classical s-process

Base time ~1 day, fast decaying nuclei are excluded (T < 3,75 h)

There are some r-nuclei


9.2 Example 2: r-process few initial nuclei ( 5103 ⋅ )

320

n cm105n −⋅= r-process without s-nuclei


9.3 Example 3: r-process a great many initial nuclei

45103 ⋅ , 319

n cm105n −⋅=

The s-nuclei appeared with two exceptions. These are and .


9.4 Example 4: m-process

AGB conditions, time dependent neutron density


10. Termination of s-process?

The passage is available if the

band reached

nuclei

(T = 33 s) .


11. The role of base time, the width of the band


12. The role of base time, the profile of the band


13. The role of neutron density, profile of the band


14. Experiences and conclusion

1. The formation of nuclei occur in a band

2. There are no r-nuclei (in exclusive meaning)

3. Most of s-nuclei can form in r-process

4. The bypass of bismuth is possible at medium neutron density

5. The m-process (medium neutron density) is very important

Example: Tellurium


15. Tellurium I.

Tellurium\A 120 122 123 124 125 126 128 130

Z=52 \ N= 68 70 71 72 73 74 76 78

Solar 0,09 2,55 0,89 4,74 7,07 18,84 31,74 34,08

s-process 0 19,16 5,42 28,02 8,60 34,81 2,99 0,00

m-process 0 5,36 1,29 5,90 5,65 28,51 37,10 15,20

r-process 0 0,00 0,00 0,00 5,87 0,22 22,34 70,57

Fitted 0 3,66 0,89 4,11 5,76 18,84 31,66 34,10

(In fact, only two parameters! if a = 1)

64.5% AGB


16. Tellurium II.

The AGB stars are important places of element formation

Fitting of the tellurium isotopes


17. Criteria

1. Traditional approach

"The success of any theory of nucleosynthesis has to be measured by comparison with the

abundance patterns observed in nature."

say Käppeler, Beer and Wisshak ,

that is, we need to create such model that gives back the observed abundance.

[F. Käppeler, H. Beer and K. Wisshak, s-process nucleosynthesis-nuclear physics and the

classical model: Rep. Prog. Phys. 52 (1989) 945-1013.]

2. New point of view

It seems that the reverse approach is also useful: the abundance is the preserver of the

nuclei’s formation conditions. So instead investigating whether the theoretical model fits

the observed abundance, we look for the circumstances when the observed abundance is

available.

[M. Kiss, NIC2014, http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=204]


18. Rate Analysis or a Possible

Interpretation of Abundances

We assume the equilibrium formation of the

nuclei. From the corresponding rate equations we

can get the required neutron density both in

isotopic and isotonic cases.


19. Isotopic case


20. Isotonic case


21. What is the range of the processes?


22. Final conclusions

All experienced isotope ratios can be obtained

both at K108 temperature and at K103 8⋅ temperature

at intermediate neutron density

31412

n cm1010n −−=

so the m-process and the AGB

stars are probably one of the main places of

nucleosynthesis.


23. References

[1] E. M. Burbidge, G. R. Burbidge, W. A. Fowler, and F. Hoyle (1957). "Synthesis of the Elements in Stars". Reviews of Modern Physics 29 (4): 547. Bibcode:1957RvMP...29..547B.

doi:10.1103/RevModPhys.29.547.

[2] F. Käppeler, H. Beer and K. Wisshak, s-process nucleosynthesis-nuclear physics and the classical model: Rep. Prog. Phys. 52 (1989) 945-1013.

[3] C. E. Rolfs, W. S. Rodney: Cauldrons in the Cosmos, The Univ. of Chicago Press, 1988

[4] K. Takahashi, K. Yokoi: BETA-DECAY RATES OF HIGHLY IONIZED HEAVY ATOMS IN STELLAR INTERIORS, ATOMIC DATA AND NUCLEAR DATA TABLES 36,375-409 (1987)]

[5] M. Kiss and Z. Trócsányi, “Phenomenological Description of Neutron Capture Cross Sections at 30 keV,” ISRN Astronomy and Astrophysics, vol. 2013, Article ID 170954, 8 pages, 2013.

doi:10.1155/2013/170954

[6] D Arnett: Supernovae and Nucleosynthesis, Princeton University Press, 1996

[7] J. J. Cowan and W. K. Rose: PRODUCTION OF 14

C AND NEUTRONS IN RED GIANTS, The Astrophysical Journal, 212:149-158, 1977 February 15

[8] R. A. Malaney, Heavy -element synthesis in AGB and post-AGB stars of low mass, Mon. Not. R. astr. Soc. (1986) 223, 709-725

[9] M. Lugaro, A. I. Karakas Sara Bisterzo Models and observations of the s process in AGB, PoS(NIC X)034, 2008:

[10] P. Prado, L. Dardalet, E. Heringer, C. Higgs, C. Ritter, S. Jones, M. Pignatari, M. Bertolli, P. Woodward, Falk Herwig, i process and CEMP-s+r stars NIC XIII. 2014

[11] M. Kiss, PhD Thesis/Egyetemi doktori (PhD) értekezés, Debreceni Egyetem Debrecen 2012

[12] http://www.kadonis.org/

[13] http://www.nndc.bnl.gov/astro/

[14] Kiss M., Trócsányi Z. A unified model for nucleosynthesis of heavy elements in stars, Journal of Physics: Conference Series (2010) 012024 doi:10.1088/1742-6596/202/1/012024

[15] J. D. Gilmour and G. Turner, CONSTRAINTS ON NUCLEOSYNTHESIS FROM XENON ISOTOPES IN PRESOLAR MATERIAL, The Astrophysical Journal, 657:600Y608, 2007 March 1

[16] T. Lebzelter, J. Hron, Technetium and the third dredge up in AGB stars I. Field stars, A&A 411, 533-542 (2003) doi: 10.1051/0004-6361:20031458

[17] R. A. MALANEY: Production of technetium in red giants by γ- ray-induced fission, Nature 337, 718 - 720 (23 February 1989); doi:10.1038/337718a0

[18] http://www.nndc.bnl.gov/astro/calcmacs.jsp

[19] Kadonis 1.0: http://exp-astro.physik.uni-frankfurt.de/kadonis1.0/


Thank you for your attention!

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Miklós Kiss Berze High School, Gyöngyös, Hungaryparrise.elte.hu/tpi-15/slides/Kiss_Miklos_Nucleosynthesis.pdf · Neutron Capture Nucleosynthesis Kiss Miklós, Berze High School