Astronomy Colloquium - Evan Kirby

Image
Crab Nebula Supernova Remnant
January 30, 2020
3:00PM - 4:00PM
Location
0130 CBEC

Date Range
Add to Calendar 2020-01-30 15:00:00 2020-01-30 16:00:00 Astronomy Colloquium - Evan Kirby Galactic Archaeology: Galaxy Formation and Nucleosynthesis Evan Kirby - California Institute of Technology Galactic archaeology is the use of the velocities and abundances of stars to learn about the history of galaxy formation and nucleosynthesis.  I will tell three stories of galactic archaeology with three different groups of elements: alpha elements, the iron peak, and the r-process. First, I will present detailed abundances of individual stars in the dwarf satellites, stellar streams, and smooth halo of M31.  The evolution of [alpha/Fe] in these stars supports the hierarchical assembly paradigm of galaxy formation. Second, I will present abundances of manganese and nickel in dwarf satellite galaxies of the Milky Way.  These abundances are best explained by a strong contribution of sub-Chandrasekhar-mass Type Ia supernovae. Third, I will present measurements of barium abundances in the globular cluster M15.  The constancy of barium from the main sequence to the red giant branch indicates that the stars in M15 were born with their unusually large dispersion of r-process elements rather than acquiring it from an external source. Coffee and Donuts will be served at 2:30pm in 4054 McPherson Lab. 0130 CBEC Department of Astronomy astronomy@osu.edu America/New_York public
Description

Galactic Archaeology: Galaxy Formation and Nucleosynthesis

Evan Kirby - California Institute of Technology

Galactic archaeology is the use of the velocities and abundances of stars to learn about the history of galaxy formation and nucleosynthesis.  I will tell three stories of galactic archaeology with three different groups of elements: alpha elements, the iron peak, and the r-process. First, I will present detailed abundances of individual stars in the dwarf satellites, stellar streams, and smooth halo of M31.  The evolution of [alpha/Fe] in these stars supports the hierarchical assembly paradigm of galaxy formation. Second, I will present abundances of manganese and nickel in dwarf satellite galaxies of the Milky Way.  These abundances are best explained by a strong contribution of sub-Chandrasekhar-mass Type Ia supernovae. Third, I will present measurements of barium abundances in the globular cluster M15.  The constancy of barium from the main sequence to the red giant branch indicates that the stars in M15 were born with their unusually large dispersion of r-process elements rather than acquiring it from an external source.

Coffee and Donuts will be served at 2:30pm in 4054 McPherson Lab.

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