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VERSION:2.0
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PRODID:UW-Madison-Physics-Events
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SEQUENCE:2
UID:UW-Physics-Event-8033
DTSTART:20221208T213000Z
DTEND:20221208T223000Z
DTSTAMP:20260414T113422Z
LAST-MODIFIED:20221123T193026Z
LOCATION:4421 Sterling Hall
SUMMARY:Linking Planet Formation to Exoplanet Composition  \, Astronom
 y Colloquium\, Prof. Edwin(Ted) Bergin\, University of Michigan
DESCRIPTION:For the past decade we have begun to explore the origin of
  planetary compositions which are set in the natal protoplanetary disk
 . In this talk I will explore these links via two lenses that of giant
  planets formed far from their star and in smaller Earth-sized planets
  in the inner regions of planetary systems. For giant planets the prim
 ary link has been through the elemental C/O ratio. This is theorized t
 o vary with position in the planet-forming disk as the main carriers o
 f C and O (H2O\, CO\, and CO2) have spatially separated gas-ice sublim
 ation fronts. I will outline the methodology via which the C/O ratio i
 s traced within disk systems using data from the Atacama Large Millime
 ter Array (ALMA). I will then summarize the state of knowledge through
  a comparison of ALMA measurements of the C/O ratio to those measured 
 with high accuracy in distant exoplanets and discuss what this means f
 or the origins of these planetary systems. For the second part of my t
 alk\, I will explore the disposition of elemental carbon via new model
  of planet formation in the inner parts of the disk. This model relate
 s the initial mantle composition of the planet to its formation zone a
 round its star\, factoring in the relative contributions of refractori
 es (metals and silicates) and volatile components (solid state organic
 s\, water vapor/ice\, and hydrogen-dominated nebular gas). We predict 
 that a population of super-Earth’s and mini-Neptune’s will form in
  particular locations in their protoplanetary disks such that they rec
 eive significant inventories of organics\, but very low amounts of wat
 er. As a result of geochemical equilibrium\, the mantle of such a plan
 et would be rich in reduced carbon but have relatively low oxygen (wat
 er) content. Outgassing would naturally yield the ingredients for haze
  production\, which is widely observed in these systems. Although this
  type of planet has no solar system counterpart\, it should be common 
 in the galaxy.
URL:https://www.physics.wisc.edu/events/?id=8033
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