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Exoplanet Seminar



Brown Dwarfs and Exoplanets: Discovery, Characterization, and High-Precision Instrumentation
Dr. Sarah Logsdon (GSFC)

In this two-part talk, I will give an overview of my ongoing research to characterize late-type brown dwarfs as well as discuss my instrumentation work in support of NEID, a precision radial velocity spectrometer. In the first part of my talk, I will highlight the results of a Keck/NIRSPEC spectroscopic follow-up survey of late-T type brown dwarfs (Teff < 1000 K) with unusual J-H colors. This survey tests the hypothesis that J-H color outliers may represent the old (high-gravity, low-metallicity) and young (low-gravity, solar-metallicity) extremes of the late-T dwarf population. I compare the target spectra to spectral standards and fit to publicly-available atmospheric model grids. The best-fit physical parameters vary depending on the atmospheric model set used, underlining the difficulty of modeling these cold objects. As the target brown dwarfs have temperatures similar to many known exoplanets, setting constraints on fundamental parameters like gravity and metallicity has implications for both brown dwarf and exoplanet atmosphere studies. In the second part of my talk, I will briefly describe the NEID instrument, an optical (380-930 nm), fiber-fed, precision Doppler spectrometer currently in development for the WIYN 3.5 m Telescope at Kitt Peak National Observatory as part of the NN-EXPLORE partnership. Designed to achieve a radial velocity precision of <30 cm/s, NEID will be sensitive enough to detect terrestrial-mass exoplanets around low-mass stars. A sub-component of NEID is the NEID Port Adapter, which delivers the incident light from the telescope to the NEID fibers. I will discuss the work we are doing at Goddard to develop tools and test plans to meet the system requirements of the NEID Port Adapter.

Date December 12, 2017
Start/End Time 01:00 PM - 02:00 PM
Location B34, E215
Event Type Seminars/Colloquia
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