[Baps] PLS Tuesday (5/10) - Exoplanet doubleheader — Prajwal Niraula (MIT) & Zoe de Beurs (MIT)

[Jason Soderblom]

Hello everyone,

Please join us next Tuesday, May 10th, for our final regularly scheduled PLS of the semester.  We will have having an exoplanet doubleheader!
For those attending in person, please RSVP here<https://docs.google.com/forms/d/e/1FAIpQLSdIK-ZPn6uBaA4dD6A3u4zTSR8EVSwTZTiTSfBatWLIkTifEg/viewform> for lunch no later than 1 PM Monday (5/9) so we can accurately gauge lunch demand.


Speaker: Prajwal Niraula (MIT)

Title: The Grand Opacity Challenge: Opacity-driven Biases in Exoplanet Atmospheric Characterization

Abstract: Remote sensing enables the study of worlds beyond Earth's neighborhood by leveraging the dependence of light-matter interaction to local conditions to gain insights into, e.g., local composition. The remote sensing of exoplanet atmospheres is currently limited by instruments. With the upcoming generation of observatories, the instrumental contribution to the overall uncertainty budget will decrease. Here, we report on the share of opacity models in this future budget. We perform a sensitivity analysis using \red{nine} different opacity cross-sections representative of standard assumptions and find that despite differences in the cross-sections, most of the retrievals produce harmonious fits owing to compensations in the form of $>$5$\sigma$ biases on the derived atmospheric parameters. These biases reveal an accuracy wall at $\sim$0.5-1.0 dex (i.e., 3 to 10$\times$), which is an order of magnitude above the precision targeted by \textit{JWST} Cycle 1 programs and needed for, e.g., \red{meaningful C/O-ratio constraints and biosignatures identification}. We suggest a two-tier approach to alleviate this problem involving a new retrieval procedure and guided improvements in opacity data, their standardization and optimal dissemination.


Speaker: Zoe de Beurs (MIT)

Title: Examining Planet-Star Interactions in HAT-P-2 b to Understand Stellar Pulsations and Hot Jupiters’ Migration.

Abstract: The role of planet-star interactions in stellar pulsations and in the inward migration of Hot Jupiters is not well understood. One possible migration mechanism proposed is that high-eccentricity gas giants experience tidal interactions with their host star that cause them to lose orbital energy and migrate to a close-in orbit. Here, we study these types of tidal interactions in an eccentric Hot Jupiter called HAT-P-2 b, which is the first system where planet-induced tidal pulsations in a host star were measured and a trend in orbital parameters was found. An additional three years of RV measurements were taken by the California Planet Search (CPS) team on the HIRES spectrograph. In this talk, we will discuss our pipeline that has confirmed a rapid change argument of periastron (ω) and eccentricity (e) from the CPS observations. These orbital parameter changes are significantly larger than what would be expected from general relativity alone and this rapid orbital evolution could be explained by tidal planet-star interactions. Thus, we will also discuss our models of the tidal pulsations observed in the star using MESA and GYRE and how these tidal pulsations relate to the rapid orbital evolution seen in HAT-P-2 b..



Logistics:
When: 12:30 PM ET, Tuesday May 10
In person: 54-517
Zoom: https://mit.zoom.us/j/92330499130
Zoom PW: Green915
RSVP for lunch here<https://docs.google.com/forms/d/e/1FAIpQLSdIK-ZPn6uBaA4dD6A3u4zTSR8EVSwTZTiTSfBatWLIkTifEg/viewform> by 1 PM Monday
Meeting signup: coming soon!

We hope to see you there!

-PLS
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