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SUMMARY:Radiation Hydrodynamics Simulations of Photoevaporating Protoplane
 tary Disks with Multi-Metallicity Chemistry
DTSTART;VALUE=DATE-TIME:20200512T113000Z
DTEND;VALUE=DATE-TIME:20200512T115000Z
DTSTAMP;VALUE=DATE-TIME:20240704T115618Z
UID:indico-contribution-6@meetings.aip.de
DESCRIPTION:Speakers: Riouhei Nakatani (RIKEN)\nRecent observations have f
 ound shorter lifetimes of protoplanetary disks (PPDs) in low-metallicity e
 nvironments than in the solar neighborhood (Yasui et al. 2009\, 2010). It 
 suggests a more efficient disk dispersal with decreasing metallicity. Prio
 r studies have shown that photoevaporation is one of the essential disk-di
 spersing mechanisms that can yield sufficient mass-loss rates consistent w
 ith observed disk lifetimes. Ercolano & Clarke (2010) have demonstrated th
 at EUV/X-ray photoevaporation potentially explains the shorter disk lifeti
 mes for low-metallicity PPDs. \n In our studies\, we implement photoelectr
 ic heating due to FUV as well as photoionization heating due to EUV/X-ray 
 and examine the effects on thermochemical structures PPDs. We perform a su
 ite of radiation hydrodynamics simulations\, varying disk metallicities\, 
 to study the effects of metallicity on thermochemical structures and photo
 evaporation. Our simulations self-consistently solve hydrodynamics\, radia
 tive transfer\, and nonequilibrium chemistry. We also consistently determi
 ne grain temperatures with 2D radiative transfer. \n The results show incr
 easing mass-loss rates as metallicity decreases at sub-solar metallicities
  owing to the reduced opacity of the disk. It is consistent with the obser
 vational trend that the lifetimes are shorter in low metallicity environme
 nts. At even lower metallicities\, dust-gas collisional cooling remains ef
 ficient compared to FUV photoelectric heating. The disk temperatures are t
 oo low to drive strong photoevaporation regardless of FUV heating. For fur
 ther lower metallicities\, dynamical time is shorter than the heating or c
 ooling timescale\, and thus the atmosphere of PPDs becomes effectively adi
 abatic. Overall\, our results show metallicity significantly affects the t
 hermochemical structures and dynamics of the PPD atmosphere.\n\nhttps://me
 etings.aip.de/event/1/contributions/6/
LOCATION:Leibniz Institute for Astrophysics Potsdam (AIP) Lecture Hall
URL:https://meetings.aip.de/event/1/contributions/6/
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