Astronomy Tea Talk

Speaker: Caprice Phillips

Title: Atmospheric Characterization of the Dusty Planetary-Mass Companion BD+60 1417B

Abstract:

In this talk, I will present a detailed characterization of the BD+60 1417 system that incorporates an atmospheric retrieval and spectroscopic variability monitoring of BD+60 1417B, elemental abundance measurements of BD+60 1417, and a spin-alignment measurement of both components. The recently discovered, L6--L8γ planetary-mass companion, BD+60 1417 B (15± 5 MJup), lies at a separation of >1000 AU from its K0 host star and has an age of 50 – 150 Myr. I use the Brewster retrieval code to test thermal profile parameterizations and ultimately detail the atmospheric composition. The retrieval results presented in this work demonstrate that the emergence of condensate cloud species complicates retrieval analysis, most notably when only near-infrared spectra are available. I will also present new spectroscopic monitoring observations of BD+60 1417B obtained with HST/WFC3. We detect significant variability across the full 1.1-1.7 micron region probed by HST that is likely driven by inhomogeneous atmospheric features such as non-uniform clouds. Our observations allow us to measure the rotation rate and viewing angle of the companion BD+60 1417B and thus test the spin axis alignment of the BD+60 1417 system. Finally, I will present the first elemental abundance measurements of the young K-dwarf, BD+60 1417. We find a relatively high Mg/Si value and a near solar C/O ratio, which allows us to predict the cloud conditions likely present in the secondary.

Please note that this is a Zoom-only talk. You can join via the following Zoom link: https://caltech.zoom.us/j/88139532758