ELFT HÍRADÓ

[vidakris AT konkoly.hu]

Szemináriumi meghívó / Invitation to a seminar
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CSFK CSI SZEMINÁRIUM / KONKOLY OBSERVATORY SEMINAR

Date: Oct 17 (Thursday) 14:00


Ulrich (Ott HUN-REN Atomki, Debrecen (Hungary), MPI for Chemistry, Mainz 
(Germany)):
Astrophysical signatures in meteorites and their components, with emphasis on 
p-process
 

Study of the isotopic compositions of meteorites and their variations has 
revealed signatures that can be related to processes of nucleosynthesis in 
stars. Generally, the size of variations scales inversely with the size of 
the phases that show such “anomalies”. For the small effects seen in “bulk” 
it is not always trivial distinguishing astrophysical variations from such of 
more mundane origin. The largest effects are seen in “pre-solar grains”, 
i.e., “stardust”, and the study of silicon carbide grains, in particular, 
provides a wealth of information on the s-process. Bulk compositions of 
primitive chondrites, on the other hand, define the “Solar System abundances”.
Among isotopic variations that are relevant with respect to p-process 
nucleosynthesis and cosmochemistry, prominent and having received the most 
attention are observations related to the presence and decay in the Early 
Solar System of now-extinct radioactive nuclides such as 92Nb, 97Tc and 
146Sm. Especially useful for setting constraints on properties of the 
p-process and possible variability are those cases where an element has more 
than one p-only isotope, like, e.g., Mo, Ru and Xe. Interestingly, Mo 
isotopes indicate no variability in the 92Mo/94Mo ratio, nor in the ratio of 
p- to r-process contributions, between presolar SiC grains and bulk meteorite 
samples (Stephan T. et al. (2019)), while (Fischer-Gödde M. et al. (2018) ) 
favor a different p/r mixing ratio for Ru in refractory metal nuggets from 
the Allende meteorite. Finally, the ratio of the two p-only Xe isotopes 
124Xe/126Xe in presolar nanodiamonds is distinctly different from that in the 
average p-process contribution to
  the Solar System.


The seminar will be held live in the Detre hall with audience, but also 
streamed online via Zoom. If you are unable to attend the presentation in 
person, you can join us via this link
https://us06web.zoom.us/j/82806911982?pwd=SVZpT0syQ1J6dHBvSkF4N2dXNEQ0dz09
or the meeting ID: 828 0691 1982 and passcode: 206265



Everyone is welcome!

Krisztián Vida, Ramon Brasser
organizers
https://konkoly.hu/k-szeminariumok