Julianne I. Moses
A5048466695- Astro and Planetary Science
- Planetary Science and Exploration
- Atmospheric Ozone and Climate
- Stellar, planetary, and galactic studies
- Space Exploration and Technology
- Isotope Analysis in Ecology
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Solar and Space Plasma Dynamics
- Spacecraft and Cryogenic Technologies
- Spectroscopy and Laser Applications
- Laser-induced spectroscopy and plasma
- Atmospheric chemistry and aerosols
- Molecular Spectroscopy and Structure
- Atmospheric and Environmental Gas Dynamics
- Geology and Paleoclimatology Research
- High-pressure geophysics and materials
- Ionosphere and magnetosphere dynamics
- Calibration and Measurement Techniques
- Atomic and Molecular Physics
- Spacecraft Design and Technology
- Methane Hydrates and Related Phenomena
- Scientific Research and Discoveries
- Gamma-ray bursts and supernovae
- Mass Spectrometry Techniques and Applications
Space Science Institute
2015-2024
Seabrook
2010-2023
Excellence Cluster Origins
2022
California Institute of Technology
1988-2021
Berkeley College
2021
Hampton University
2021
University of California, Santa Cruz
2021
University of California, Berkeley
2021
Sinclair Pharma
2021
Search for Extraterrestrial Intelligence
2021
We have developed a one-dimensional photochemical and thermochemical kinetics diffusion model to study the effects of disequilibrium chemistry on atmospheric composition "hot-Jupiter" exoplanets. Here we investigate coupled neutral carbon, hydrogen, oxygen, nitrogen species HD 189733b 209458b compare results with existing transit eclipse observations. find that vertical profiles molecular constituents are significantly affected by transport-induced quenching photochemistry, particularly...
Motivated by recent spectroscopic evidence for carbon-rich atmospheres on some transiting exo-planets, we investigate the influence of C/O ratio chemistry, composition, and spectra extrasolar giant planets both from a thermochemical-equilibrium perspective consideration disequilibrium processes like photochemistry transport-induced quenching. We find that although CO is predicted to be major atmospheric constituent hot Jupiters all ratios, other oxygen-bearing molecules H2O CO2 are much more...
Neptune-sized extrasolar planets that orbit relatively close to their host stars -- often called "hot Neptunes" are common within the known population of exoplanets and planetary candidates. Similar our own Uranus Neptune, inefficient accretion nebular gas is expected produce hot Neptunes whose masses dominated by elements heavier than hydrogen helium. At high atmospheric metallicities 10-10,000x solar, will exhibit an interesting continuum compositions, ranging from more Neptune-like,...
Measuring the abundances of carbon and oxygen in exoplanet atmospheres is considered a crucial avenue for unlocking formation evolution exoplanetary systems. Access to an exoplanet's chemical inventory requires high-precision observations, often inferred from individual molecular detections with low-resolution space-based high-resolution ground-based facilities. Here we report medium-resolution (R$\sim$600) transmission spectrum atmosphere between 3-5 $\mu$m covering multiple absorption...
Abstract Carbon dioxide (CO 2 ) is a key chemical species that found in wide range of planetary atmospheres. In the context exoplanets, CO an indicator metal enrichment (that is, elements heavier than helium, also called ‘metallicity’) 1–3 , and thus formation processes primary atmospheres hot gas giants 4–6 . It one most promising to detect secondary terrestrial exoplanets 7–9 Previous photometric measurements transiting planets with Spitzer Space Telescope have given hints presence but not...
Photochemistry is a fundamental process of planetary atmospheres that regulates the atmospheric composition and stability. However, no unambiguous photochemical products have been detected in exoplanet to date. Recent observations from JWST Transiting Exoplanet Early Release Science Program found spectral absorption feature at 4.05 $\mu$m arising SO$_2$ atmosphere WASP-39b. WASP-39b 1.27-Jupiter-radii, Saturn-mass (0.28 M$_J$) gas giant orbiting Sun-like star with an equilibrium temperature...
Abstract The search for habitable environments and biomarkers in exoplanetary atmospheres is the holy grail of exoplanet science. detection atmospheric signatures Earth-like exoplanets challenging owing to their small planet–star size contrast thin with high mean molecular weight. Recently, a new class exoplanets, called Hycean worlds, has been proposed, defined as temperate ocean-covered worlds H 2 -rich atmospheres. Their large sizes extended atmospheres, compared rocky planets same mass,...
Abstract Hot Jupiters are among the best-studied exoplanets, but it is still poorly understood how their chemical composition and cloud properties vary with longitude. Theoretical models predict that clouds may condense on nightside molecular abundances can be driven out of equilibrium by zonal winds. Here we report a phase-resolved emission spectrum hot Jupiter WASP-43b measured from 5 μm to 12 JWST’s Mid-Infrared Instrument. The spectra reveal large day–night temperature contrast (with...
The recent inference of sulfur dioxide (SO2) in the atmosphere hot (approximately 1,100 K), Saturn-mass exoplanet WASP-39b from near-infrared JWST observations1-3 suggests that photochemistry is a key process high-temperature atmospheres4. This because low (<1 ppb) abundance SO2 under thermochemical equilibrium compared with produced H2O and H2S (1-10 ppm)4-9. However, was made single, small molecular feature transmission spectrum at 4.05 μm and, therefore, detection other absorption bands...
We have developed a one‐dimensional, diurnally averaged, photochemical model for Jupiter's stratosphere that couples photodissociation, chemical kinetics, vertical diffusion, and radiative transport. The predictions regarding the abundances profiles of hydrocarbon compounds are compared with observations from Infrared Space Observatory (ISO) to better constrain atmospheric composition, define eddy diffusion coefficient profile, understand reaction schemes produce destroy observed...
Characterizing the atmospheres of extrasolar planets is new frontier in exoplanetary science. The last two decades exoplanet discoveries have revealed that exoplanets are very common and extremely diverse their orbital bulk properties. We now enter a era as we begin to investigate chemical diversity exoplanets, atmospheric interior processes, formation conditions. Recent developments field led unprecedented advancements our understanding chemistry implications for review these present work....
The James Webb Space Telescope (JWST) presents the opportunity to transform our understanding of planets and origins life by revealing atmospheric compositions, structures, dynamics transiting exoplanets in unprecedented detail. However, high-precision, timeseries observations required for such investigations have unique technical challenges, prior experience with Hubble, Spitzer, other facilities indicates that there will be a steep learning curve when JWST becomes operational. In this...
We use a 1D model to address photochemistry and possible haze formation in the irradiated warm Jupiter, 51 Eridani b. The intended focus was be carbon, but sulfur turns out important. case for organic photochemical hazes is intriguing falls short of being compelling. If form, they are likeliest do so if vertical mixing Eri b weaker than would found below altitudes where methane water photolyzed. more novel result that H$_2$S into elemental sulfur, here treated as S$_8$. In cooler models,...
We explore quench kinetics in the atmospheres of substellar objects using updated timescale arguments, as suggested by a thermochemical and diffusion model that transitions from thermochemical-equilibrium regime deep atmosphere to quench-chemical at higher altitudes. More specifically, we examine CO chemistry on T dwarf Gliese 229B CH4 hot-Jupiter HD 189733b. describe method for correctly calculating reverse rate coefficients chemical reactions, discuss predominant pathways interconversion...
Chemical kinetics plays an important role in controlling the atmospheric composition of all planetary atmospheres, including those extrasolar planets. For hottest exoplanets, can closely follow thermochemical-equilibrium predictions, at least visible and infrared photosphere dayside (eclipse) conditions. However, for temperatures < ~2000 K, uppermost atmosphere any temperature, chemical matters. The two key mechanisms by which kinetic processes drive exoplanet out equilibrium are...
Abstract UV radiation can induce photochemical processes in exoplanet atmospheres and produce haze particles. Recent observations suggest that and/or cloud layers could be present the upper of exoplanets. Haze particles play an important role planetary may provide a source organic material to surface impact origin or evolution life. However, very little information is known about cool, high-metallicity exoplanetary atmospheres. Previously, we investigated formation particle size distribution...