Subaru Seminars



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The Subaru Seminar is usually held in Room 104 of the Hilo Base Facility, adjacent to the main lobby. Everyone is welcome to attend. If you are interested in giving a seminar, please contact Subaru seminar organizers (Tomonori Usuda, Kumiko S. Usuda, Masahiko Hayashi, Masayuki Akiyama) by email.

January 31, Monday at 11:00am

" Chemical Evolution of the Galaxy's Thick Disk and Outer Disk"

Bruce W. Carney (University of North Carolina)

Evidence will be reviewed regarding the age of the Galaxy's thick disk, and new observations of the behavior of metallicity vs. kinematics, and elemental abundances relative to iron for a sample of thin disk and thick disk stars will be presented. In combination with other larger surveys, it appears that the thick disk has experienced a very different chemical evolution than the thin disk, and that it may well have arisen from an independent galaxy's merger with the Milky Way. There are even signs of an enhanced star formation rate in the old thin disk following the merger. An exploration of elemental abundance patterns of the outer Galactic disk will also be explored. It appears that, contrary to model expectations, the radial metallicity gradient in the outer disk disappears beyond a Galactocentric distance of about 12 kpc. The light elements Mg, Si, Ca, and Ti, and the heavy element Eu, are enhanced relative to iron, suggesting dominance of Type II supernovae and a vigorous star formation rate, which also suggests mergers of low-metallicity material has contributed to the growth of the Galactic disk.

Seminars are also held at JAC, CFHT, and IfA.

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