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SUMMARY:Migration of snowlines through the planet-forming discs - Olja Pan
 ic (IoA)
DTSTART:20141008T153000Z
DTEND:20141008T163000Z
UID:TALK55105@talks.cam.ac.uk
CONTACT:Dr B.-O. Demory
DESCRIPTION:The condensation fronts of some of the main molecular species 
 like H2O and CO are points of significant discontinuity for the chemical c
 omposition of gas and the fraction of ice in solids. Both properties are c
 rucial in determining whether a planet may form and what atmospheric compo
 sition it may have. The location of the CO snowline is determined by both 
 irradiation by the central star and the capability of the disc to capture 
 the stellar photons\, while for the H2O snowline accretion is an additiona
 l efficient source of heating.\n\nWe carried out a grid-based exploration 
 of disc structure models to investigate how disc evolution processes affec
 t the temperature of the planet-forming midplane. We find that as a result
  of gas loss and grain growth – both known to take place over the severa
 l Myr of disc lifetime – snow fronts are pushed closer to the star by 50
 % or more. If the CO snowline fosters formation of planets like Uranus and
  Neptune\, as suggested recently\, our results show that this effect is no
 t limited to a low density outer region of the disc but planets may form p
 rogressively at different locations as the CO snowline migrates towards de
 nser regions. This work also implies that the highest value of the C/O rat
 io in disc gas may be reached much closer to the star than previously thou
 ght.\n\nRecently it has been shown that the CO snowline can be imaged usin
 g submillimetre interferometric imaging of N2H or DCO in discs. This is a 
 promising method to obtain observational constraints on the physical condi
 tions of planet forming regions in statistically significant samples of di
 scs very soon\, considering ALMA sensitivity and resolution.\n
LOCATION:Martin Ryle Seminar Room\, Kavli Institute
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