Origins of the Isotopes Workshop

28 Sept 2021, 07:00 → 30 Sept 2021, 19:00 America/New_York

Alexander Ji (University of Chicago), Andy Casey (Monash University), Reto Trappitsch (Brandeis University)

A short two-half-day workshop of invited talks and discussion to kickstart collaboration between presolar grain measurements, stellar chemical abundances, nucleosynthesis, and galactic chemical evolution.

A series of online discussion-only sessions will be organized following the workshop.

Final times:

Sep 28, 2021; from 7-10am EDT (4-7am PDT, 1-4pm CEST, 9pm-midnight AEST)

Sep 30, 2021; from 4-7pm EDT (1-4pm PDT, 10pm-2am CEST, 6am-9am AEST on Oct 1)
[Please note this day has changed from what was originally posted on the website!]

 

Invited Speakers:

Maria Bergemann
Benoit Cote
Camilla Hansen
Erika Holmbeck
Amanda Karakas
Larry Nittler
Marco Pignatari
Thomas Stephan
Francois Tissot
 

Program to come.

 

This workshop is sponsored by IReNA: https://www.irenaweb.org/

Due to an error, the IReNA code of conduct was not previously included in the registration form. If you registered without agreeing to it, please fill out an additional form agreeing to the code of conduct.

 

Slack Information and Introduction

Welcome Slides

Tuesday 28 September

07:00 → 07:10 Welcome

07:10 → 07:40 Amanda Karakas - Nucleosynthesis models of low-mass stars and their connection to stardust grains

I plan to give an overview of the theoretical modelling of low-mass stars, with a focus on the nucleosynthesis during the asymptotic giant branch (AGB). I will provide a brief overview of AGB nucleosynthesis models and compare model predictions to grain data. I will finish with a comment on open problems and future opportunities.

07:40 → 08:10 Maria Bergemann - Making sense of chemical fingerprints in stellar spectra: the devil is in the details

The observed trends of chemical abundance ratios in the Milky Way provide stringent constraints on nucleosynthesis and models of galactic chemical evolution. Many of us are wondering: are high quality spectra sufficient to obtain accurate (or precise) abundances? I will focus on recent developments in the field of theoretical diagnostic spectroscopy. I will highlight two classes of cases: those that demand more sophisticated modelling with effects of 3D radiation transfer, convection, and non-LTE, and those that are nearly invariant to how we model stellar atmospheres. I will also discuss how the new 3D NLTE models change our understanding of Galactic abundance trends and influence their astrophysical interpretation.

08:20 → 08:50 Marco Pignatari - The origin of stardust grains from different astrophysical sites

08:50 → 09:20 Camilla Juul Hansen - Isotopes and elements in very metal-poor stars

In the talk I will focus on the chemical composition in very metal-poor, low-mass stars and which elements and isotopes we can measure and derive abundances of in these. In particular I will talk about CEMP stars, as well as the first low-mass stars and finding ones that show mono enrichment. Finally, I will briefly touch on Ru and Mo in stars vs grains.

09:30 → 10:00 Larry Nittler - Presolar Stardust and the Origin of the Isotopes

This talk will provide an overview of presolar grains in meteorites and their implications for stellar nucleosynthesis, with an emphasis on recent developments and current frontiers.

Thursday 30 September

16:00 → 16:30 Benoit Cote - Chemical evolution of stable and radioactive isotopes

I will present how to model the evolution stable and radioactive isotopes in our Galaxy, in order to explore and quantify the role of different astrophysical sites on the origin of isotopes. I will discuss some of the current challenges in interpreting the isotopic composition of the Solar System, as well highlighting the need for multi-disciplinary collaborations.

16:30 → 17:00 Thomas Stephan - Origin of Molybdenum and Ruthenium Isotopes Inferred from Presolar Silicon Carbide Grains

We have analyzed Mo and Ru isotopes in presolar SiC grains with high precision using the Chicago Instrument for Laser Ionization (CHILI). The results (1) allow to determine the s-process contributions to the various Mo and Ru isotopes, (2) show a clear correlation between s-process signatures in Mo and Ru, (3) provide some insights into the variability of conditions (neutron density, temperature, and timescales) during s-process nucleosynthesis, and (4) suggest a fixed ratio between p- and r-process isotopes in presolar SiC from many different types of parent stars.

17:10 → 17:40 Francois Tissot - Nucleosynthetic anomalies in the Solar System

This talk will provide an overview on nucleosynthetic anomalies, from their discovery, to their instrumental role in establishing genetic relationship between planetary bodies as well as revealing the structure of the early solar system. We will discuss the constraints these signatures have brought us so far, and the remaining limitations that future works should tackle.

17:40 → 18:10 Erika Holmbeck - The Production of the Heaviest Elements through the Nuclear Lens

Our understanding of the production of the heaviest elements by the rapid neutron-capture ("r-") process involves many uncertainties, both in the astrophysical site in which the r-process takes place and in the nuclear physics that determine key properties of the isotopes at play. This talk will explore the impact of nuclear uncertainties on r-process observables and discuss how isotopic - rather than elemental - abundances may be able to shed light on some of the unknowns involved in how the heaviest elements were synthesized.

18:20 → 19:00 Discussion and Followup Topic Determination