ExoLunch - spring-2024
Addressing the challenges in understanding the nature of exoplanet atmospheres from their spectra
April 9, 2024
3:30 p.m. - 4:30 p.m.
3853 Slichter Hall
Presented By:
- Luis Welbanks - Arizona State University
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The 2020s and beyond will be the era of spectroscopy of exoplanet atmospheres. In just 3 years, our field has made dramatic advancements, moving from having very limited wavelength coverage and precision data from the Hubble Space Telescope (HST), to having high-precision spectroscopy over a wide wavelength range (~0.4 to 20μm) with the James Webb Space Telescope (JWST). These exquisite observations come with the opportunity to perform detailed reconnaissance of exoplanet atmospheres, explore their chemical and physical properties, and perform population-level studies to test our hypotheses for planet formation and planetary processes. Thanks to these advancements we could very well be the first generation in human history to answer whether we are alone in the universe. However, any interpretation is only as good as our understanding of the limits of the data and the model assumptions themselves, a point often overlooked. Whether exploring hot gas giants or temperate terrestrial exoplanets, the future of the field depends on our models' ability to interpret atmospheric properties from observed spectra. This new era in exoplanetary sciences invites us to overcome previous artificial boundaries between observers and theorist and merging both disciplines to fully exploit this wealth of data. In this talk, I will present my efforts to deliver a holistic view of exoplanet atmospheres, answering not only what exoplanet atmospheres are made of, but also which data drive our inferences, how reliable these inferences are, and their place within the larger astronomical context. I will present several early ground-breaking results from observations with JWST. From these observations we detect and constrain several chemical species that were previously elusive, including methane (CH4), ammonia (NH3), sulfur dioxide (SO2), carbon monoxide (CO), and carbon dioxide (CO2), alongside several precise water (H2O) measurements. I will discuss the challenges we are currently facing, and the advancements required for inferring the complete chemical inventory of our diverse exoplanet sample. Our findings underscore the transformative power of JWST and pave the way for future, in-depth atmospheric investigations of a larger exoplanet population.
A Comprehensive Framework for Modeling Photochemistry, Climate, and Habitability
April 16, 2024
3:30 p.m. - 4:30 p.m.
3853 Slichter Hall
Presented By:
- Shang- Min Tsai - UC Riverside
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Exoplanet science has rapidly progressed, transitioning from the stage of detection to atmospheric characterization. The diversity of exoplanets broadens our understanding of planetary science and provides a profound perspective on the evolution of our world. In this talk, I will give an overview of exoplanet characterization methods and the fundamental processes governing atmospheric composition. I will highlight recent JWST findings, including the first detection of photochemistry in an exoplanet atmosphere and its implications for understanding planet formation. I will address the necessity of moving beyond 1D modeling, to account for global and temporal properties. By employing a 2D—3D modeling framework, I reveal distinct spectral features and limb asymmetries relevant to transit and phase-curve observations. I will discuss the puzzles surrounding the most common class of planets, known as sub-Neptunes, which curiously find no analogues in our Solar System. I will demonstrate how studying their atmospheres can help break the internal structure degeneracies. Lastly, did JWST detect signs of life on the sub-Neptune exoplanet K2-18b? I will share our recent insights into probing microbial life on oceanic sub-Neptune exoplanets.
Transforming exoplanet atmospheric and interior characterisation in the JWST era (and beyond)
April 23, 2024
3:30 p.m. - 4:30 p.m.
3853 Slichter Hall
Presented By:
- Matt Nixon - University of Maryland
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The study of exoplanetary systems holds the promise of helping humanity to better understand its place in the universe. Measuring the chemical composition of exoplanets allows us to test formation and evolutionary hypotheses and search for signs of life, making it a crucial step towards characterizing the exoplanet population and putting our Solar System in context. JWST is providing the observational capability to characterize exoplanets in much more detail than has previously been possible, and promises to answer several long-standing questions in the field. However, while our capacity to observe exoplanet atmospheres is being revolutionized, significant advances in modeling are also required to deliver on these promises. In this talk, I will present ongoing work to transform the way we model exoplanet atmospheres and interiors. I will show how combining the power of different models can allow us to place more robust constraints on an exoplanet’s composition, which can help to avoid biased inferences. For giant planets, I will highlight the importance of moving from 1D to 3D models when fitting JWST data in order to accurately constrain atmospheric properties. For sub-Neptunes, I will discuss how to connect both atmospheric and interior models to observations in order to break crucial degeneracies and truly characterize this mysterious population. These modeling improvements will help us to maximize the scientific return from JWST, while setting the stage for longer-term advances in our understanding of exoplanets from upcoming facilities.
Transforming exoplanet atmospheric and interior characterization in the JWST era (and beyond)
April 23, 2024
3:30 p.m. - 4:30 p.m.
Slichter Hall 3853
Presented By:
- Matt Nixon - University of Maryland
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The study of exoplanetary systems holds the promise of helping humanity to better understand its place in the universe. Measuring the chemical composition of exoplanets allows us to test formation and evolutionary hypotheses and search for signs of life, making it a crucial step towards characterizing the exoplanet population and putting our Solar System in context. JWST is providing the observational capability to characterize exoplanets in much more detail than has previously been possible, and promises to answer several long-standing questions in the field. However, while our capacity to observe exoplanet atmospheres is being revolutionized, significant advances in modeling are also required to deliver on these promises. In this talk, I will present ongoing work to transform the way we model exoplanet atmospheres and interiors. I will show how combining the power of different models can allow us to place more robust constraints on an exoplanet’s composition, which can help to avoid biased inferences. For giant planets, I will highlight the importance of moving from 1D to 3D models when fitting JWST data in order to accurately constrain atmospheric properties. For sub-Neptunes, I will discuss how to connect both atmospheric and interior models to observations in order to break crucial degeneracies and truly characterize this mysterious population. These modeling improvements will help us to maximize the scientific return from JWST, while setting the stage for longer-term advances in our understanding of exoplanets from upcoming facilities.
A New Era of Planetary Science with JWST and High-Resolution Spectrographs
April 30, 2024
3:30 p.m. - 4:30 p.m.
Slichter Hall 3853
Presented By:
- Bjorn Benneke - University of Montreal
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We are at the dawn of a new era of planetary science, marked by groundbreaking discoveries and rapid advances in our understanding of planets and their atmospheres in the most general way. The opportunity is no less than to assess the full diversity of the planets in the Universe, to understand their climatic states, and to finally answer humanity's millennia-old questions of "How did we get here?" and "Are we alone?" In this colloquium, I will give you a first glimpse of this new era by showing how our early results from JWST and high-resolution spectrographs are already challenging many long-held ideas in planetary science. I will present new "hot off the press" JWST results that are fundamentally changing our understanding of the likely most common type of planet in the Universe, with masses between Earth and Neptune. I will also discuss how our ongoing observations are advancing our understanding of planet formation and evolution, and finally, I will present the first JWST spectroscopic results for habitable-zone rocky worlds outside the Solar System and our next steps to further characterize them.