Please join us this Wednesday (9/17) for a talk at 2pm by Li Zeng, who will be visiting us from Harvard. Li works with Dimitar Sasselov and Stein Jacobsen on understanding the chemistry of Earth-like planets. His abstract is included below. It should be a very interesting talk! As always, tea and treats will be served.
This week, we will be meeting in a ***NEW LOCATION, ROOM 37-656*** which is on the sixth floor of the same building where we’ve held our last few meetings (MIT Building 37 at 70 Vassar Street).
Uncovering the Chemistry of Earth-like Planets
We propose to use evidence from our solar system to understand exoplanets, and in particular, to predict their surface chemistry and thereby the possibility of life. An Earth-like planet, born from the same nebula as its host star, is composed primarily of silicate rocks and an iron-nickel metal core, and depleted in volatile content in a systematic manner. The more volatile (easier to vaporize or dissociate into gas form) an element is in an Earth-like planet, the more depleted the element is compared to its host star. After depletion, an Earth-like planet would go through the process of core formation due to heat from radioactive decay and collisions. Core formation depletes a planet’s rocky mantle of siderophile (iron-loving) elements, in addition to the volatile depletion. After that, Earth-like planets likely accrete some volatile-rich materials, called “late veneer”. The late veneer could be essential to the origins of life on Earth and Earth-like planets, as it also delivers the volatiles such as nitrogen, sulfur, carbon and water to the planet’s surface, which are crucial for life to occur. We plan to build an integrative model of Earth-like planets from the bottom up. We would like to infer their chemical compositions from their mass-radius relations and their host stars’ elemental abundances, and understand the origins of volatile contents (especially water) on their surfaces, and thereby shed light on the origins of life on them.