Observing the signature of a single prolific r-process event in an ultra-faint dwarf galaxy

Frebel, Anna

Title:

Observing the signature of a single prolific r-process event in an ultra-faint dwarf galaxy

dc.contributor.author	Frebel, Anna
dc.contributor.corporatename	Georgia Institute of Technology. School of Physics	en_US
dc.contributor.corporatename	Massachusetts Institute of Technology. Dept. of Physics	en_US
dc.date.accessioned	2017-11-02T19:13:08Z
dc.date.available	2017-11-02T19:13:08Z
dc.date.issued	2017-10-23
dc.description	Presented on October 23, 2017 at 3:00 p.m. in the Marcus Nanotechnology Building, Room 1116-1118.	en_US
dc.description	After studying physics in Germany, Anna Frebel received her PhD from the Australian National University's Mt. Stromlo Observatory in 2006, advised by Prof. John E. Norris. In early 2012 Dr. Frebel joined the MIT physics faculty as Assistant Professor.	en_US
dc.description	Runtime: 58:51 minutes	en_US
dc.description.abstract	The heaviest chemical elements in the periodic table are synthesized through the rapid neutron-capture (r-) process but the astrophysical site where r-process nucleosynthesis occurs is still unknown. The best candidate sites are ordinary core-collapse supernovae and mergers of binary neutron stars. Through their stars, 13 billion year old ultra-faint dwarf galaxies preserve a "fossil" record of early chemical enrichment that provides the means to isolate and study clean signatures of individual nucleosynthesis events. Until now, ultra-faint dwarf galaxy stars displayed extremely low abundances of heavy elements (e.g. Sr, Ba). This supported supernovae as the main r-process site. But based on new spectroscopic data from the Magellan Telescope, we have found seven stars in the recently discovered ultra-faint dwarf Reticulum II that show extreme r-process overabundances, comparable only to the most extreme ancient r-process enhanced stars of the Milky Way's halo. This r-process enhancement implies that the r-process material in Reticulum II was synthesized in a single prolific event. Our results are clearly incompatible with r-process yields from an ordinary core-collapse supernova but instead consistent with that of a neutron star merger. This first signature of a neutron star merger in the early universe holds the key to finally, after 60 years, identifying the cosmic r-process production site, in addition to being a uniquely stringent constraint on the metal mixing and star formation history of this galaxy from the early universe.	en_US
dc.format.extent	58:51 minutes
dc.identifier.uri	http://hdl.handle.net/1853/58860
dc.language.iso	en_US	en_US
dc.publisher	Georgia Institute of Technology	en_US
dc.relation.ispartofseries	Physics Colloquium
dc.subject	Astronomy	en_US
dc.subject	Neutron stars	en_US
dc.subject	Nucleosynthesis	en_US
dc.subject	Stars	en_US
dc.title	Observing the signature of a single prolific r-process event in an ultra-faint dwarf galaxy	en_US
dc.type	Moving Image
dc.type.genre	Lecture
dspace.entity.type	Publication
local.contributor.corporatename	College of Sciences
local.contributor.corporatename	School of Physics
local.relation.ispartofseries	Physics Colloquium
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relation.isOrgUnitOfPublication	2ba39017-11f1-40f4-9bc5-66f17b8f1539
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