June 11, 2021

The ExoExplorer Science Series presents talks by cohort members Kaitlin Rasmussen (U Michigan) and Eileen Gonzales (Cornell) on June 11 from 1-2 PM Pacific / 4-5 PM Eastern. Connection information is below.

Speaker: Eileen Gonzales (Cornell)

Title: Why Brown Dwarfs Should Be Your Friends: Lessons Learned From Their Atmospheric Retrievals

Abstract: Brown dwarfs are objects that straddle the mass boundary between stars and planets. With temperatures ranging from ~250-3,000K, brown dwarfs lie in the same range as those of directly imaged exoplanets. Their plentiful and exquisite spectra available make brown dwarfs prime exoplanet analogs for interpreting atmospheric features. Retrievals provide a powerful data-driven technique to delve into questions about the chemistry and atmospheric properties of substellar objects. In this talk, I will discuss lessons learned from spectral retrievals of brown dwarfs using the Brewster retrieval framework. I will present preliminary results from a comparative sample of field sources to the subdwarf SDSS J1416A to determine how their Pressure-Temperature profiles compare to one another to explore what may drive the differences in their spectra. In doing so, I will tell a cautionary tale in trusting retrieval results. Additionally, I will discuss the results of the unusually red L dwarf 2MASS 2224 to explore the nature of clouds and the power of wide spectral coverage.

Speaker: Kaitlin Rasmussen (U Michigan)

Title: The Hitchhiker’s Guide to the Drake Equation: Past, Present, and Future

Abstract: Far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the Galaxy, the ape-descended lifeforms of an utterly insignificant planet asked a question: "Are we alone?" Frank Drake had an answer: Given a handful of statistics about the local universe, one could calculate the number of intelligent civilizations currently residing in the Milky Way. Today, the Drake Equation poses a serious question in astrophysics: how can we better constrain those statistics? In this talk, I will discuss a variety of approaches to studying the detection, formation rates, and biosignatures of exoplanets, and how they point toward a better understanding of sentient life in the Universe.

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