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| Uncovering the Chemistry of Earth-like Planets |
| Li Zeng |
| Thursday, Apr 9, 2015 at 8:00 PM |
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| 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.
Speaker Bio
I am originally from Chongqing, China. I received Bachelor of Science Degree in Physics from MIT.
As a 6th-year PhD graduate student now in the Department of Astronomy at Harvard University, I have been working with my research advisor Professor Dimitar Sasselov on interior structure modeling of exoplanets. Recently, I have been collaborating with Professor Stein Jacobsen and Dr. Michail Petaev in the Department of Earth & Planetary Sciences on implementing elemental abundance calculation and mixing calculation to model the chemistry of Earth-like planets.
I am also interested in Traditional Chinese Martial Arts, Medicine, and Healing. I currently serve as the President of Harvard GSAS Anlin Taichi Wudao Association (Oriental Traditional Culture, Science, and Research Association).
Please join us for a pre-meeting dinner discussion at Changsho, 1712 Mass Ave, Cambridge, MA at 6:00pm before the meeting. |
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