Clemson University

Colloquium, Dr. Anna Frebel, MIT

Colloquium

Department of Physics and Astronomy

Kinard G01, Kinard Lab of Physics

Thursday, February 11, 4:00 pm

 

Hunting the first generations of stars and galaxies

 

Abstract: The new Australian SkyMapper 1.3m telescope is carrying out a photometric survey of the entire Southern Sky. From using ugriz filter plus an additional narrow filter placed at the Ca K line at 3933A, stellar parameters can be obtained for all stars observed. This allows for an efficient selection of a variety of stellar types, including metal-poor stars. Recent efforts to search for the most metal-poor stars have indeed delivered a new record holder for the most iron-poor star: no iron lines were detected in the high-resolution follow-up Magellan spectrum and only an upper limit of [Fe/H]<-7.1 could be determined. Contrary to its iron deficiency, the star has a significant amount of carbon. This abundance pattern can be explained with the star being a second-generation star in the universe which formed from a gas cloud enriched by only one PopIII first star. What was the environment in which these early stellar generations formed? A spectroscopic study of the faintest dwarf galaxy Segue 1 has shed light on this question. Given the chemical abundance patterns of some of its only few stars) with metallicities ranging from -4 < [Fe/H] < -1) suggest that this tiny galaxy may be a surviving first galaxy from the early universe. This suggestion is in line with recent age measurements for similar ultra-faint dwarfs, which showed these galaxies to be single-age stellar systems that are about as old as the universe itself.

 

Bio Sketch: Anna Frebel is an Assistant Professor of Physics at the Massachusetts Institute of Technology (MIT). She has received numerous international honors and awards for her discoveries and subsequent chemical abundance analyses of the oldest stars and how these stars can be employed to uncover information about the early Universe some 13 billion years ago. Prof. Frebel has authored more than 70 papers in various refereed journals, and enjoys communicating science to the public through public lectures, magazine articles, interviews as well as her popular science book "Searching for the oldest stars" (2015, by Princeton University Press).

 

Refreshments will be served in the PandA Café after the colloquium.

Thursday, February 11, 2016 at 4:00pm to 5:00pm

Kinard Laboratory of Physics, G01 Kinard Lab
140 Delta Epsilon Ct., Clemson, SC 29634, USA

Notice of Non-Discrimination

Event Type

Lectures / Seminars / Speakers, Seminars

Target Audience

Students, Faculty, Undergraduate, Graduate

Departments

College of Engineering, Computing and Applied Sciences, Physics and Astronomy

Contact Name:

Amanda Ellenburg

Contact Phone:

656-0343

Contact Email:

aellenb@clemson.edu

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