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SUMMARY:Deciphering giant planet formation - Olja Panic (Leeds)
DTSTART:20250513T120000Z
DTEND:20250513T130000Z
UID:TALK227281@talks.cam.ac.uk
CONTACT:Dr Dolev Bashi
DESCRIPTION:The multitude of detected exoplanets and their diversity never
  cease to fascinate us\, while the statistical trends emerging from these 
 detections present promising opportunities to delve into the past of plane
 tary systems\, all the way back to their formation.  In this talk\, I will
  give an overview of my group's recent observational and theoretical resul
 ts on the formation of gas giants. Owing to their large gravitational infl
 uence these planets cannot be overlooked in the evolution of planetary sys
 tems towards a life-harbouring system such as our own. Results of RV and d
 irect imaging surveys in recent years revealed that gas giants are not a c
 ommon outcome of planet formation\, and that their most frequent hosts - t
 he intermediate-mass stars (IMSs) seem to hold the answers to their format
 ion.\n\nWe investigate the formation of giant planets using the pebble-acc
 retion driven planet formation simulations\, exploring a range of differen
 t formation conditions.\nIn this work\, and in contrast to common approach
 es in the literature\, we implement stellar-mass dependent time evolution 
 of luminosity on the pre-main sequence\, and find that this makes a signif
 icant difference to giant planet formation outcomes. We successfully repro
 duce the giant planet occurrence rates as a function of stellar mass\, fou
 nd by RV surveys. This work revealed that mass accretion rate is the key p
 arameter in determining whether a star will likely host a giant planet in 
 its future planetary system.\n\nOur large surveys of pre-main sequence sta
 r candidates led to the first unbiased sample of such IMSs\, and the resul
 t that their protoplanetary discs are dispersed faster than discs around l
 ow mass stars\, a devastating prospect for giant planet formation unless i
 t happens very fast (e.g.\, via GI). This is in stark contrast with the ob
 servational examples of massive discs actively forming planets at 5-6Myr o
 f age. Our work shows that late gas accretion\, as seen in some of those s
 ources\, must be the dominant mechanism that sustains the mass reservoir o
 f these older protoplanetary discs. Our surveys\, and follow-up with ALMA 
 also allowed a unique insight in the elusive transition state from protopl
 anetary to debris discs and origin of gas in debris discs.
LOCATION:Ryle seminar room + ONLINE - Details to be sent by email
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