BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:3
UID:UW-Physics-Event-6343
DTSTART:20210914T220000Z
DURATION:PT1H0M0S
DTSTAMP:20260414T193125Z
LAST-MODIFIED:20210908T105425Z
LOCATION:https://berkeley.zoom.us/j/99464252867
SUMMARY:The Milky Way is not special: accreted stars also inhabit the 
 Spite Plateau\, Network in Neutrinos\, Nuclear Astrophysics\, and Symm
 etries (N3AS) Seminar\, Dr. Jeffrey Simpson\, UNSW\, Australia
DESCRIPTION:The ESA Gaia astrometric mission has enabled the remarkabl
 e discovery that a large fraction of the stars within a few kiloparsec
 s of the Sun appear to be debris from a single in-falling system\, the
  so-called Gaia-Sausage-Enceladus. One exciting feature of this result
  is that it gives astronomers for the first time a large sample of eas
 ily observable\, unevolved stars that formed in an extra-Galactic envi
 ronment\, which can be compared to stars that formed within our Milky 
 Way. In this talk I will discuss using these stars to investigate the 
 "Spite Plateau" – the near-constant lithium abundance observed in me
 tal-poor dwarf stars across a wide range of metallicities (-3 < [Fe/H]
  < -1). In particular our aim was to test whether the stars that forme
 d in Gaia-Sausage-Enceladus show a different Spite Plateau to Milky Wa
 y stars that inhabit the disk and halo. Individual galaxies could have
  different Spite Plateaus – e.g.\, the interstellar medium could be 
 more depleted in lithium in a lower galactic mass system due to it hav
 ing a smaller reservoir of gas. We find that the Gaia-Sausage-Enceladu
 s stars show the same lithium abundance as other likely accreted stars
  and in situ Milky Way stars\, strongly suggesting that the "lithium p
 roblem" is not a consequence of the formation environment. This result
  fits within the growing consensus that the Spite Plateau\, and more g
 enerally the "cosmological lithium problem" – the observed discrepan
 cy between the amount of lithium in warm\, metal-poor dwarf stars in o
 ur Galaxy\, and the amount of lithium predicted to have been produced 
 by Big Bang Nucleosynthesis – is the result of lithium depletion pro
 cesses within stars.
URL:https://www.physics.wisc.edu/events/?id=6343
END:VEVENT
END:VCALENDAR