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BEGIN:VEVENT
DTSTART;TZID=Atlantic/Canary:20200630T123000
DTEND;TZID=Atlantic/Canary:20200630T133000
UID:iactalks-1411
X-WR-CALNAME: IAC Talks: Open Astronomy Seminars
X-ORIGINAL-URL: /iactalks/Talks/view/1411
CREATED:2020-06-30T12:30:00+01:00
X-WR-CALDESC: IAC Talks upcomming talks
SUMMARY:Mass-Metallicity Trends in Transiting Exoplanets
DESCRIPTION:Mass-Metallicity Trends in Transiting Exoplanets\nLuis Welbanks
 \n\nAtmospheric compositions can provide powerful diagnostics of formation
  and migration histories of planetary systems. In this talk, I will presen
 t the results of our latest survey of atmospheric compositions focused on 
 atmospheric abundances of H2O, Na, and K. We employ a sample of 19 exoplan
 ets spanning from cool mini-Neptunes to hot Jupiters, with equilibrium tem
 peratures between ~300 and 2700 K. We employ the latest transmission spect
 ra, new H2 broadened opacities of Na and K, and homogeneous Bayesian retri
 evals. We confirm detections of H2O in 14 planets and detections of Na and
  K in 6 planets each. Among our sample, we find a mass-metallicity trend o
 f increasing H2O abundances with decreasing mass, spanning generally subst
 ellar values for gas giants and stellar/superstellar for Neptunes and mini
 -Neptunes. However, the overall trend in H2O abundances, is significantly 
 lower than the mass-metallicity relation for carbon in the solar system gi
 ant planets and similar predictions for exoplanets. On the other hand, the
  Na and K abundances for the gas giants are stellar or superstellar, consi
 stent with each other, and generally consistent with the solar system meta
 llicity trend. The H2O abundances in hot gas giants are likely due to low 
 oxygen abundances relative to other elements rather than low overall metal
 licities, and provide new constraints on their formation mechanisms. Our r
 esults show that the differing trends in the abundances of species argue a
 gainst the use of chemical equilibrium models with metallicity as one free
  parameter in atmospheric retrievals, as different elements can be differe
 ntly enhanced.\n\nZoom link: https://rediris.zoom.us/j/92734027825
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