BEGIN:VCALENDAR VERSION:2.0 PRODID:icalendar-ruby CALSCALE:GREGORIAN X-WR-CALNAME:Planetary Science and Exploration Seminar\, Andrea Zorzi and M att Reinhold X-WR-TIMEZONE:Pacific Time (US & Canada) BEGIN:VEVENT DTSTAMP:20260616T060924Z UID:tag:localist.com\,2008:EventInstance_48553937015163 DTSTART:20250115T203000Z DTEND:20250115T212000Z DESCRIPTION:Andrea Zorzi\, Earth and Planetary Science PhD student\, Stanfo rd\n\nTitle: Impact induced formation of prebiotic molecules on terrestria l planets\n\nAbstract: New chemical species can form from reactions induce d by shock-heating upon formation of an impact vapor plume and its interac tion with the background atmosphere of a rocky planet. Previous studies ha ve assumed chemical equilibrium in computing the abundance of chemical spe cies: such a simplified model can underestimate those concentrations by a factor of 10 in high-temperature shock conditions. A more accurate descrip tion of the plume/atmosphere interaction demands a coupled hydrodynamics a nd kinetics calculation. We present a new model extending the work of Ishi maru et al. (2010) by considering an atmosphere on the target planet. We a ssess the production of prebiotic molecules (HCN\, CH4\, NH3) for differen t impact scenarios\, varying kinetic energy of the impactor\, atmospheric surface density and composition. We find that prebiotic species are produc ed on Earth-like planets with a N2-CH4 atmosphere. The presence of oxygen in today’s inner solar system planets prevents the production of HCN. On Titan\, impacts can constitute an additional sink for methane. For Archea n Earth conditions\, it is possible to form HCN and CH4. Our findings prov ide necessary but not sufficient conditions for prebiotic chemistry to sta rt\, to assess the astrobiological potential of impacts on terrestrial wor lds.\n\n \n\nMatt Reinhold\, Earth and Planetary Science PhD Student\, Sta nford\n\nTitle: Ignan Earths: Habitability of Terrestrial Planets with Ex treme Internal Heating\n\nAbstract: Is it possible for a rocky planet to h ave too much internal heating to maintain a habitable surface environment? In the Solar System\, the best example of a world with high internal heat ing is Jupiter's moon Io\, which has a heat flux of approximately 2 W/m^2 compared to the Earth's 90 mW/m^2 . The ultimate upper limit to internal h eating rates is the Tidal Venus Limit\, where the geothermal heat flux exc eeds the Runaway Greenhouse Limit of 300 W/m^2 for an Earth-mass planet. B etween Io and a Tidal Venus there is a wide range of internal heating rate s whose effects on planetary habitability remain unexplored. We investigat e the habitability of these worlds\, referred to as Ignan Earth's. We demo nstrate how the mantle will remain largely solid despite high internal hea ting\, allowing for the formation of a convectively buoyant and stable cru st. In addition\, we model the long-term climate of Ignan Earth's by simul ating the carbonate-silicate cycle in a vertical tectonic regime (known as heat-pipe tectonics\, expected to dominate on such worlds) at varying amo unts of internal heating. We find that Earth-mass planets with internal he ating fluxes below 15 W/m^2 produce average surface temperatures that Ear th has experienced in its past (below 30 C)\, and worlds with significantl y higher heat fluxes still result in surface temperatures far below that o f 100 C\, indicating a wide range of internal heating rates may be conduci ve with habitability.\n\n \n\n \n\nLunch held at Mitchell Earth Sciences p atio\, 12:00pm GEO:37.426402;-122.172635 LOCATION:Mitchell Earth Sciences\, B67 SUMMARY:Planetary Science and Exploration Seminar\, Andrea Zorzi and Matt R einhold URL;VALUE=URI:https://events.stanford.edu/event/planetary-science-and-explo ration-seminar-andrea-zorzi-and-matt-reinhold CATEGORIES:Class/Seminar END:VEVENT END:VCALENDAR