NUCLEOSYNTHESIS, THE R-NUCLEOSYNTHESIS, THE R-PROCESS, ABUNDANCES AND PROCESS, ABUNDANCES AND

JIM TRURAN JIM TRURAN

J. J. COWANJ. J. COWAN

University of OklahomaUniversity of Oklahoma

JINA Frontiers 2010 : Workshop on Nuclear Astrophysics Yerkes Observatory - October 21, 2010

Abundance Clues and ConstraintsAbundance Clues and Constraints

New observations of n-capture elements in low-New observations of n-capture elements in low-metallicity Galactic halo stars providing clues and metallicity Galactic halo stars providing clues and constraints on:constraints on:

1.1. Synthesis mechanisms for heavy elements early in Synthesis mechanisms for heavy elements early in the history of the Galaxy the history of the Galaxy

2.2. Identities of earliest stellar generations, the Identities of earliest stellar generations, the progenitors of the halo starsprogenitors of the halo stars

3. Suggestions on sites, particularly site or sites for the 3. Suggestions on sites, particularly site or sites for the r-processr-process

4.4. Galactic chemical evolutionGalactic chemical evolution

5.5. Ages of the stars and the Galaxy chronometersAges of the stars and the Galaxy chronometers

r-process synthesis

Jim has contributed in all of these areas of study

2MASS View of the Milky Way2MASS View of the Milky WayGalactic Halo Stars

back

• Metal-poor Halo Stars are ``fossils’’ of the Early Universe• These Stars are Relatives of the First Stars in the Universe

r-Process Nucleosynthesisr-Process Nucleosynthesis

• For the r-process: For the r-process: • ττncnc << << ττββ decay decay

(typically 0.01–(typically 0.01–0.1 s)0.1 s)• Site for the Site for the r-process still notr-process still notstill not identifiedstill not identified

Despite decades of effort by Jim and others

Jim’s Approach to LifeJim’s Approach to Life

WorkingWorking Playing

Most Likely Site(s) for the r-ProcessMost Likely Site(s) for the r-Process

Supernovae: The Prime SuspectsSupernovae: The Prime Suspects Regions just outside neutronized Regions just outside neutronized

core: 1957 (Woosley et al. 1994; core: 1957 (Woosley et al. 1994; Wanajo et al. 2002) (Wanajo et al. 2002) (νν-wind)-wind)

Prompt explosions of low-mass Prompt explosions of low-mass Type II SNe (Wheeler, JC & Type II SNe (Wheeler, JC & Hillebrandt 1998)Hillebrandt 1998)

He shells (Truran et al. 1978); He shells (Truran et al. 1978); Jets and bubbles (Cameron 2001)Jets and bubbles (Cameron 2001)

NS & NS-BH mergers (Rosswog NS & NS-BH mergers (Rosswog et al. 1999; Freiburghaus et al. et al. 1999; Freiburghaus et al. 1999)1999)

Trying to think outside the boxTrying to think outside the boxAnd trying not to get And trying not to get tangled up in details.tangled up in details.

n-Capture Abundances in n-Capture Abundances in CS 22892-052CS 22892-052

Very old star.Robust r-process overthe history ofthe Galaxy.

Stellar elemental abundances consistent with scaled SS r-process only

Historical(~ 1996)

Even s-processelements likeBa made in r-process early in theGalaxy.Predicted byTruran (1981)

Very little datathen

Rare Earth Abundances in Five Rare Earth Abundances in Five r-Rich Stars: New Atomic Datar-Rich Stars: New Atomic Data

Sneden et al. (2009)

Comparisonsof new REEabundances with SS r-only predictions All

normalized to Eu

Verylittlescatter

CS 22892-052 AbundancesCS 22892-052 Abundances

Log ε(A) = Log10(NA/NH) + 12

Germanium

Platinum

(with new atomic and stellar data)

57 elementsobserved.More than anystar exceptthe Sun.

(64 HST Orbits)

31 N-Capture Elements Detected The Old King

Al Cameron Watching Over UsAl Cameron Watching Over Us

Then …Then …And NowAnd Now

New Abundance Detections of Cd I, New Abundance Detections of Cd I, Lu II and Os II in BD +17 3248Lu II and Os II in BD +17 3248

First detections of these n-cap species in metal-poor stars

Roederer et al. (2010)

Cadmium: Good in Stars, Bad in Cadmium: Good in Stars, Bad in People!People!

Heavy MetalHeavy Metal: It is not as pervasive as : It is not as pervasive as lead. But a study is underway to establish lead. But a study is underway to establish safe levels of safe levels of cadmiumcadmium..

McDonald’s recently recalled 12 million McDonald’s recently recalled 12 million Shrek-themed glasses because of concern Shrek-themed glasses because of concern about the level of about the level of cadmiumcadmium contained in contained in the enamel. the enamel.

Time Magazine – July 12, 2010

Abundances in BD+17 3248: Meet Abundances in BD+17 3248: Meet the New King!the New King!

32 n-capture elements detected in BD +17 3248 Most in any metal-poor halo star to date!

Consistency for r-Rich StarsConsistency for r-Rich Stars

10 r-process rich stars

Same abundance pattern at the upper end and ? at the lower end.

CS 22892-052HD 115444BD +17 3248CS 31082-001HD 221170HE 1523-0901CS 22953-03HE 2327-5642CS 2941-069HE 1219-0312

But Differences Between r-rich and But Differences Between r-rich and r-poor Starsr-poor Stars

r-process rich

r-process poor

Roederer et al. (2010)

Note generalfall off

incompleter-process

Looking at a Range of r-Process Looking at a Range of r-Process RichnessRichness

Eu/Fe

(r-processrichness)

The ubiqiuity of the r-process (Roederer et al. 2010)

r-Process Rich vs. r-Process Poorr-Process Rich vs. r-Process Poor

Origin of the Lighter n-Capture Origin of the Lighter n-Capture Elements: Work in ProgressElements: Work in Progress

See Roederer et al. (2010)

Looking for Inspiration or Looking for Inspiration or Advice?Advice?

Lighter n-Cap Element Origin?Lighter n-Cap Element Origin? Weak r-process, classical wp approximation, Weak r-process, classical wp approximation,

lower n-number densitieslower n-number densities More sophisticated: alpha-rich freeze-out/HEW More sophisticated: alpha-rich freeze-out/HEW

(Kratz and Farouqi et al.) makes many of the (Kratz and Farouqi et al.) makes many of the elements from Sr-Pd but not Ag and Cdelements from Sr-Pd but not Ag and Cd

What about LEPP (Travaglio et al. and Montes What about LEPP (Travaglio et al. and Montes et al.)?et al.)?

For some elements like Ge (and others?) For some elements like Ge (and others?) nu-p process (Frohlich et al. ) nu-p process (Frohlich et al. )

Maybe multiple processes?Maybe multiple processes?

Traveling the WorldTraveling the World

Always Willing to Pitch InAlways Willing to Pitch In Closest Approach to a ChurchClosest Approach to a Church

CosmochronometersCosmochronometers

[irrelevant; decays too quickly]

Rolfs & Rodney (1988)

Th Detections in Four Halo Stars Th Detections in Four Halo Stars and the Sun and the Sun

Note the strengthof the Th linesindependent ofmetallicity

Radioactive Age EstimatesRadioactive Age Estimates

Can use the radioactive elements (Th and U) to Can use the radioactive elements (Th and U) to make chronometric age determinationsmake chronometric age determinations

For r-rich stars consistent abundance patterns, For r-rich stars consistent abundance patterns, excluding ``actinide boost stars’’excluding ``actinide boost stars’’

ages depends sensitively on observations and ages depends sensitively on observations and production ratios production ratios

Still many uncertainties, but independent Still many uncertainties, but independent technique generally agrees with other estimatestechnique generally agrees with other estimates

Note Jim’s involvement over decades Note Jim’s involvement over decades

Some of Jim’s Important PapersSome of Jim’s Important Papers Truran, Arnett & Cameron (1967) Nucleosynthesis in Supernova Shock Truran, Arnett & Cameron (1967) Nucleosynthesis in Supernova Shock

WavesWaves Arnett & Truran (1969) Carbon Burning Nucleosynthesis at Constant Arnett & Truran (1969) Carbon Burning Nucleosynthesis at Constant

TemperatureTemperature Starrfield, Sparks & Truran (1974) CNO Abundances and Hydrodynamic Starrfield, Sparks & Truran (1974) CNO Abundances and Hydrodynamic

Models of the Nova OutburstModels of the Nova Outburst Cameron & Truran (1977) The Supernova Trigger for the Formation of the Cameron & Truran (1977) The Supernova Trigger for the Formation of the

Solar SystemSolar System Truran, Cowan & Cameron (1978) The Helium Driven r-Process in Truran, Cowan & Cameron (1978) The Helium Driven r-Process in

SupernovaeSupernovae Truran (1981) A New Interpretation of the Heavy Element Abundances in Truran (1981) A New Interpretation of the Heavy Element Abundances in

Metal-deficient StarsMetal-deficient Stars Cowan, Thielemann & Truran (1991) The r-Process and NucleochronologyCowan, Thielemann & Truran (1991) The r-Process and Nucleochronology Fields, Truran & Cowan (2002) A Simple Model for r-Process Scatter and Fields, Truran & Cowan (2002) A Simple Model for r-Process Scatter and

Halo EvolutionHalo Evolution Truran et al. (2002) Probing the Neutron Capture Nucleosynthesis History of Truran et al. (2002) Probing the Neutron Capture Nucleosynthesis History of

Galactic MatterGalactic Matter

Some Concluding Thoughts on: Some Concluding Thoughts on: Nucleosynthesis and AbundancesNucleosynthesis and Abundances

r-process elements observed in very metal-poor r-process elements observed in very metal-poor (old) halo stars – they are ubiquitous(old) halo stars – they are ubiquitous

Implies that r-process sites, earliest stellar Implies that r-process sites, earliest stellar generations rapidly evolving: live and die, eject generations rapidly evolving: live and die, eject r-process material into ISM prior to formation of r-process material into ISM prior to formation of halo stars exact site still unknown halo stars exact site still unknown

Elements (even s-process ones like Ba) Elements (even s-process ones like Ba) produced in r-process early in Galaxy – produced in r-process early in Galaxy – predicted by JWTpredicted by JWT

Origin of lighter n-cap elements still uncertain.Origin of lighter n-cap elements still uncertain. Chronometers: interesting results still uncertainChronometers: interesting results still uncertain JWT major contributor but lots of work to do! JWT major contributor but lots of work to do!

With family and friendsWith family and friends

HAPPY 70HAPPY 70THTH BIRTHDAY BIRTHDAY JIMJIM

With Collaborators at:With Collaborators at:

U. of TexasU. of Texas MSUMSU U. of ChicagoU. of Chicago CaltechCaltech MITMIT Carnegie Obs.Carnegie Obs.

U. of WisconsinU. of Wisconsin U. of MainzU. of Mainz Obs. de ParisObs. de Paris U. of BaselU. of Basel U. di TorinoU. di Torino ESOESO

With generous support from: the National Science Foundation & the Space Telescope Science Institute.

Rapid Neutron Capture in Type II Rapid Neutron Capture in Type II SNe ?SNe ?

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