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NUCLEOSYNTHESIS, THE R- PROCESS, ABUNDANCES AND JIM TRURAN J. J. COWAN University of Oklahoma JINA Frontiers 2010 : Workshop on Nuclear Astrophysics Yerkes.

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Presentation on theme: "NUCLEOSYNTHESIS, THE R- PROCESS, ABUNDANCES AND JIM TRURAN J. J. COWAN University of Oklahoma JINA Frontiers 2010 : Workshop on Nuclear Astrophysics Yerkes."— Presentation transcript:

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2 NUCLEOSYNTHESIS, THE R- PROCESS, ABUNDANCES AND JIM TRURAN J. J. COWAN University of Oklahoma JINA Frontiers 2010 : Workshop on Nuclear Astrophysics Yerkes Observatory - October 21, 2010

3 Abundance Clues and Constraints New observations of n-capture elements in low- metallicity Galactic halo stars providing clues and constraints on: New observations of n-capture elements in low- metallicity Galactic halo stars providing clues and constraints on:halo stars halo stars 1.Synthesis mechanisms for heavy elements early in the history of the Galaxy 2.Identities of earliest stellar generations, the progenitors of the halo stars 3. Suggestions on sites, particularly site or sites for the r-process 4.Galactic chemical evolution 5.Ages of the stars and the Galaxy chronometers r-process synthesis Jim has contributed in all of these areas of study

4 2MASS View of the Milky Way Galactic Halo Stars back Metal-poor Halo Stars are ``fossils’’ of the Early Universe These Stars are Relatives of the First Stars in the Universe

5 r-Process Nucleosynthesis For the r-process: For the r-process: τ nc << τ β decay τ nc << τ β decay (typically 0.01– 0.1 s) Site for the Site for the r-process still not still not identified Despite decades of effort by Jim and others

6 Jim’s Approach to Life Working Playing

7 Most Likely Site(s) for the r- Process Supernovae: The Prime Suspects Supernovae: The Prime Suspects Regions just outside neutronized core: 1957 (Woosley et al. 1994; Wanajo et al. 2002) (ν-wind) Regions just outside neutronized core: 1957 (Woosley et al. 1994; Wanajo et al. 2002) (ν-wind)(ν-wind)(ν-wind) Prompt explosions of low-mass Type II SNe (Wheeler, JC & Hillebrandt 1998) Prompt explosions of low-mass Type II SNe (Wheeler, JC & Hillebrandt 1998) He shells (Truran et al. 1978); Jets and bubbles (Cameron 2001) He shells (Truran et al. 1978); Jets and bubbles (Cameron 2001) NS & NS-BH mergers (Rosswog et al. 1999; Freiburghaus et al. 1999) NS & NS-BH mergers (Rosswog et al. 1999; Freiburghaus et al. 1999)

8 Trying to think outside the box And trying not to get tangled up in details.

9 n-Capture Abundances in CS Very old star. Robust r-process over the history of the Galaxy. Stellar elemental abundances consistent with scaled SS r-process only Historical (~ 1996) Even s-process elements like Ba made in r-process early in the Galaxy. Predicted by Truran (1981) Very little data then

10 Rare Earth Abundances in Five r-Rich Stars: New Atomic Data Sneden et al. (2009) Comparisons of new REE abundances with SS r-only predictions All normalized to Eu Very little scatter

11 CS Abundances Log ε(A) = Log 10 (N A /N H ) + 12 Germanium Platinum (with new atomic and stellar data) 57 elements observed. More than any star except the Sun. (64 HST Orbits) 31 N-Capture Elements DetectedThe Old King

12 Al Cameron Watching Over Us Then … And Now

13 New Abundance Detections of Cd I, Lu II and Os II in BD First detections of these n-cap species in metal-poor stars Roederer et al. (2010)

14 Cadmium: Good in Stars, Bad in People! Heavy Metal: It is not as pervasive as lead. But a study is underway to establish safe levels of cadmium. Heavy Metal: It is not as pervasive as lead. But a study is underway to establish safe levels of cadmium. McDonald’s recently recalled 12 million Shrek-themed glasses because of concern about the level of cadmium contained in the enamel. McDonald’s recently recalled 12 million Shrek-themed glasses because of concern about the level of cadmium contained in the enamel. Time Magazine – July 12, 2010

15 Abundances in BD : Meet the New King! 32 n-capture elements detected in BD Most in any metal-poor halo star to date!

16 Consistency for r-Rich Stars 10 r-process rich stars Same abundance pattern at the upper end and ? at the lower end. CS HD BD CS HD HE CS HE CS HE

17 But Differences Between r-rich and r-poor Stars r-process rich r-process poor Roederer et al. (2010) Note general fall off incomplete r-process

18 Looking at a Range of r-Process Richness Eu/Fe (r-process richness) The ubiqiuity of the r-process (Roederer et al. 2010)

19 r-Process Rich vs. r-Process Poor

20 Origin of the Lighter n-Capture Elements: Work in Progress See Roederer et al. (2010)

21 Looking for Inspiration or Advice?

22 Lighter n-Cap Element Origin? Weak r-process, classical wp approximation, lower n-number densities Weak r-process, classical wp approximation, lower n-number densities More sophisticated: alpha-rich freeze-out/HEW (Kratz and Farouqi et al.) makes many of the elements from Sr-Pd but not Ag and Cd More sophisticated: alpha-rich freeze-out/HEW (Kratz and Farouqi et al.) makes many of the elements from Sr-Pd but not Ag and Cd What about LEPP (Travaglio et al. and Montes et al.)? What about LEPP (Travaglio et al. and Montes et al.)? For some elements like Ge (and others?) nu-p process (Frohlich et al. ) For some elements like Ge (and others?) nu-p process (Frohlich et al. ) Maybe multiple processes? Maybe multiple processes?

23 Traveling the World Always Willing to Pitch In Closest Approach to a Church

24 Cosmochronometers [irrelevant; decays too quickly] Rolfs & Rodney (1988)

25 Th Detections in Four Halo Stars and the Sun Note the strength of the Th lines independent of metallicity

26 Radioactive Age Estimates Can use the radioactive elements (Th and U) to make chronometric age determinations Can use the radioactive elements (Th and U) to make chronometric age determinations For r-rich stars consistent abundance patterns, excluding ``actinide boost stars’’ For r-rich stars consistent abundance patterns, excluding ``actinide boost stars’’ ages depends sensitively on observations and production ratios ages depends sensitively on observations and production ratios Still many uncertainties, but independent technique generally agrees with other estimates Still many uncertainties, but independent technique generally agrees with other estimates Note Jim’s involvement over decades Note Jim’s involvement over decades

27 Some of Jim’s Important Papers Some of Jim’s Important Papers Truran, Arnett & Cameron (1967) Nucleosynthesis in Supernova Shock Waves Truran, Arnett & Cameron (1967) Nucleosynthesis in Supernova Shock Waves Arnett & Truran (1969) Carbon Burning Nucleosynthesis at Constant Temperature Arnett & Truran (1969) Carbon Burning Nucleosynthesis at Constant Temperature Starrfield, Sparks & Truran (1974) CNO Abundances and Hydrodynamic Models of the Nova Outburst Starrfield, Sparks & Truran (1974) CNO Abundances and Hydrodynamic Models of the Nova Outburst Cameron & Truran (1977) The Supernova Trigger for the Formation of the Solar System Cameron & Truran (1977) The Supernova Trigger for the Formation of the Solar System Truran, Cowan & Cameron (1978) The Helium Driven r- Process in Supernovae Truran, Cowan & Cameron (1978) The Helium Driven r- Process in Supernovae Truran (1981) A New Interpretation of the Heavy Element Abundances in Metal-deficient Stars Truran (1981) A New Interpretation of the Heavy Element Abundances in Metal-deficient Stars Cowan, Thielemann & Truran (1991) The r-Process and Nucleochronology Cowan, Thielemann & Truran (1991) The r-Process and Nucleochronology Fields, Truran & Cowan (2002) A Simple Model for r- Process Scatter and Halo Evolution Fields, Truran & Cowan (2002) A Simple Model for r- Process Scatter and Halo Evolution Truran et al. (2002) Probing the Neutron Capture Nucleosynthesis History of Galactic Matter Truran et al. (2002) Probing the Neutron Capture Nucleosynthesis History of Galactic Matter Truran

28 Some Concluding Thoughts on: Nucleosynthesis and Abundances r-process elements observed in very metal-poor (old) halo stars – they are ubiquitous r-process elements observed in very metal-poor (old) halo stars – they are ubiquitous Implies that r-process sites, earliest stellar generations rapidly evolving: live and die, eject r-process material into ISM prior to formation of halo stars exact site still unknown Implies that r-process sites, earliest stellar generations rapidly evolving: live and die, eject r-process material into ISM prior to formation of halo stars exact site still unknown Elements (even s-process ones like Ba) produced in r-process early in Galaxy – predicted by JWT Elements (even s-process ones like Ba) produced in r-process early in Galaxy – predicted by JWT Origin of lighter n-cap elements still uncertain. Origin of lighter n-cap elements still uncertain. Chronometers: interesting results still uncertain Chronometers: interesting results still uncertain JWT major contributor but lots of work to do! JWT major contributor but lots of work to do!

29 With family and friends

30 HAPPY 70 TH BIRTHDAY JIM

31 With Collaborators at: U. of Texas U. of Texas MSU MSU U. of Chicago U. of Chicago Caltech Caltech MIT MIT Carnegie Obs. Carnegie Obs. U. of Wisconsin U. of Wisconsin U. of Mainz U. of Mainz Obs. de Paris Obs. de Paris U. of Basel U. of Basel U. di Torino U. di Torino ESO ESO With generous support from: the National Science Foundation & the Space Telescope Science Institute.

32 Rapid Neutron Capture in Type II SNe ? back


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