Article
Astronomy & Astrophysics
Ryoichi Koga, Tatsuya Suzuki, Fuminori Tsuchiya, Takeshi Sakanoi, Yasuhiro Hirahara
Summary: By analyzing ALMA archive data, the study detected the submillimeter spectrum of SO2 gas from volcanic plumes and lava areas on Jupiter's moon Io, with high intensity areas of SO2 found to be associated with volcanically active regions. Column densities and temperature changes before and after eclipse suggest volcanic eruptions maintain the atmosphere, while atmospheric SO2 around Janus Patera may be supplied by evaporation from lava areas after eclipse.
ASTROPHYSICAL JOURNAL LETTERS
(2021)
Article
Astronomy & Astrophysics
D. -D. Niu, J. Cui, H. Gu, X. -S. Wu, Y. -T. Cao, L. -K. Dai, M. -Y. Wu, T. -L. Zhang, Z. -J. Rong, Y. Wei
Summary: The study utilizes measurements from instruments on board the Mars Atmosphere and Volatile Evolution spacecraft to analyze the heating rates of neutrals, ions, and electrons on the nightside of Mars. It is found that nightside neutral heating is primarily influenced by exothermic chemistry and interaction with thermal ions, while ion heating is mainly driven by energetic ion production.
ASTROPHYSICAL JOURNAL
(2021)
Article
Multidisciplinary Sciences
Maggie A. Thompson, Joshua Krissansen-Totton, Nicholas Wogan, Myriam Telus, Jonathan J. Fortney
Summary: Methane has been proposed as a potential biosignature for exoplanets, but it is important to consider the specific planetary conditions. Methane has a short lifetime in terrestrial planet atmospheres and requires large replenishment fluxes. While methane can be produced abiotically, known abiotic processes cannot easily generate atmospheres rich in methane and carbon dioxide with limited carbon monoxide. Therefore, planets with certain conditions are more likely to have biogenic methane.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Review
Multidisciplinary Sciences
Yao Chang, Michael N. R. Ashfold, Kaijun Yuan, Xueming Yang
Summary: This review highlights the rich photochemistry of triatomic molecules in the vacuum ultraviolet region and discusses their potential implications for our understanding of interstellar chemistry and molecular evolution in the universe. The study focuses on the photofragmentation dynamics of five triatomic molecules-H2O, H2S, CO2, OCS, and CS2-using the recently constructed VUV free electron laser. The review aims to provide new photochemical insights, explore the implications of this photochemistry for interstellar chemistry, and identify future research directions in chemical reaction dynamics and astrochemistry enabled by VUV-FEL sources.
NATIONAL SCIENCE REVIEW
(2023)
Article
Geochemistry & Geophysics
M. L. Wong, A. Prabhu, J. Williams, S. M. Morrison, R. M. Hazen
Summary: Previous studies have found that Earth's atmospheric chemical reaction network has a unique structure distinct from other planetary atmospheres in the Solar System. By investigating the topologies of different planetary atmospheres using network science and graph theory techniques, we show that Earth's network stands out with its nonrandom topology and similarity to biological networks. Furthermore, we discuss the potential development of a network-based biosignature applicable to exoplanets through further investigations using advanced network representations and novel network metrics.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2023)
Article
Geochemistry & Geophysics
Laura K. Schaefer, Vivien Parmentier
Summary: The atmospheric composition of rocky exoplanets is influenced by their bulk composition and orbital position. While hot planets may have nontraditional gases, clement planets depend on volatile richness acquired during planet formation. Future observatories will enhance precision in probing exoplanet atmospheres, presenting new challenges for terrestrial planet observations.
Article
Astronomy & Astrophysics
Julianne Moses, Zarah L. Brown, Tommi T. Koskinen, Leigh N. Fletcher, Joseph Serigano, Sandrine Guerlet, Luke Moore, J. Hunter Waite, Lotfi Ben-Jaffel, Marina Galand, Joshua M. Chadney, Sarah M. Horst, James A. Sinclair, Veronique Vuitton, Ingo Muller-Wodarg
Summary: During the Grand Finale stage of the Cassini mission, researchers discovered the flow of organic-rich ring material into Saturn's equatorial upper atmosphere. Through photochemical models, they studied the impact of this material on the composition of Saturn's atmosphere. However, observations did not confirm the predicted chemical consequences, leading to the conclusion that the ring influx may have been a transient event triggered by a recent dynamical event or that the material entered the atmosphere in the form of small dust particles.
News Item
Multidisciplinary Sciences
Elizabeth Gibney
Summary: Scientists are determining the time that local atomic clocks will keep for satellite navigation systems in lunar settlements.
News Item
Multidisciplinary Sciences
Myriam Vidal Valero
Summary: The need for future missions to the planet becomes more apparent after NASA puts one mission on hold.
Article
Astronomy & Astrophysics
Munazza K. Alam, Mercedes Lopez-Morales, Ryan J. MacDonald, Nikolay Nikolov, James Kirk, Jayesh M. Goyal, David K. Sing, Hannah R. Wakeford, Alexander D. Rathcke, Drake L. Deming, Jorge Sanz-Forcada, Nikole K. Lewis, Joanna K. Barstow, Thomas Mikal-Evans, Lars A. Buchhave
Summary: Exoplanets with cloud-free, haze-free atmospheres are important for detailed atmospheric characterization and precise chemical abundance constraints. The study presents the first transmission spectrum of WASP-62b, showing Na i and SiH spectral features. Using simulated observations, it is demonstrated that the James Webb Space Telescope can conclusively detect various molecules in the atmosphere of WASP-62b, making it a benchmark giant exoplanet for atmospheric characterization.
ASTROPHYSICAL JOURNAL LETTERS
(2021)
Review
Astronomy & Astrophysics
Christophe Sotin, Klara Kalousova, Gabriel Tobie
Summary: The Cassini-Huygens mission revolutionized our understanding of Titan, the only known moon with a dense atmosphere and stable surface liquids, through exploration of the Saturn system from 2004 to 2017. It revealed Titan as an ocean world, with differentiation into a hydrosphere and rocky core. The presence of organic molecules synthesized and sedimented on Titan's surface, along with interactions between water, rock, and organics, have strong astrobiological implications. Further exploration by the Dragonfly mission and comparison with data from JUICE for Ganymede will reveal Titan's astrobiology potential.
ANNUAL REVIEW OF EARTH AND PLANETARY SCIENCES, VOL 49, 2021
(2021)
Article
Astronomy & Astrophysics
Nikolay Nikolov, Gracjan Maciejewski, Savvas Constantinou, Nikku Madhusudhan, Jonathan J. Fortney, Barry Smalley, Aarynn L. Carter, Ernst J. W. de Mooij, Benjamin Drummond, Neale P. Gibson, Christiane Helling, Nathan Mayne, Thomas Mikal-Evans, David K. Sing, Jamie Wilson
Summary: The study presents a ground-based optical transmission spectrum for the warm Saturn-mass exoplanet WASP-110b using the FOcal Reducer and Spectrograph on the Very Large Telescope. Analysis of high-resolution optical spectroscopy reveals evidence of a cloud deck in the planet's atmosphere, which may affect its transmission spectrum characteristics.
ASTRONOMICAL JOURNAL
(2021)
Article
Geochemistry & Geophysics
Jianping Huang, Zhaopeng Wu, Jun Cui, Xin Wan, Jiahao Zhong, Yongqiang Hao
Summary: This study used a full-wave model to simulate the observed gravity wave structure on Titan and found that gravity waves could significantly modify the temperature structure of the upper atmosphere. The thermal effect of gravity waves is sensitive to eddy viscosity.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2022)
Article
Astronomy & Astrophysics
Giuseppe Morello, Camilla Danielski, Subhajit Sarkar
Summary: The tables provided contain stellar limb-darkening coefficients for the Ariel ESA M4 space mission, corresponding to different wavelength bins and white bands for various spectrographs and photometers. The coefficients are calculated using three grids of stellar atmosphere models obtained with the ATLAS9 and PHOENIX codes, covering wide ranges of stellar parameters. Comparisons are made between the models in the ATLAS9 and PHOENIX grids in terms of limb-darkening coefficients.
EXPERIMENTAL ASTRONOMY
(2022)
News Item
Multidisciplinary Sciences
Alexandra Witze
Summary: The telescope is providing a wealth of information about protoplanetary disks.
Article
Astronomy & Astrophysics
Sebastien Rodriguez, Sandrine Vinatier, Daniel Cordier, Gabriel Tobie, Richard K. Achterberg, Carrie M. Anderson, Sarah Badman, Jason W. Barnes, Erika L. Barth, Bruno Bezard, Nathalie Carrasco, Benjamin Charnay, Roger N. Clark, Patrice Coll, Thomas Cornet, Athena Coustenis, Isabelle Couturier-Tamburelli, Michel Dobrijevic, F. Michael Flasar, Remco de Kok, Caroline Freissinet, Marina Galand, Thomas Gautier, Wolf D. Geppert, Caitlin A. Griffith, Murthy S. Gudipati, Lina Z. Hadid, Alexander G. Hayes, Amanda R. Hendrix, Ralf Jaumann, Donald E. Jennings, Antoine Jolly, Klara Kalousova, Tommi T. Koskinen, Panayotis Lavvas, Sebastien Lebonnois, Jean-Pierre Lebreton, Alice Le Gall, Emmanuel Lellouch, Stephane Le Mouelic, Rosaly M. C. Lopes, Juan M. Lora, Ralph D. Lorenz, Antoine Lucas, Shannon MacKenzie, Michael J. Malaska, Kathleen Mandt, Marco Mastrogiuseppe, Claire E. Newman, Conor A. Nixon, Jani Radebaugh, Scot C. Rafkin, Pascal Rannou, Ella M. Sciamma-O'Brien, Jason M. Soderblom, Anezina Solomonidou, Christophe Sotin, Katrin Stephan, Darrell Strobel, Cyril Szopa, Nicholas A. Teanby, Elizabeth P. Turtle, Veronique Vuitton, Robert A. West
Summary: In response to ESA's Voyage 2050 announcement, the proposed POSEIDON mission aims to explore Saturn's largest moon, Titan, through joint orbital and in situ investigations. The mission aims to exceed the accomplishments of the Cassini-Huygens mission and explore Titan's northern latitudes in complement with NASA's upcoming Dragonfly mission. The ideal arrival time at Titan would be slightly before the next northern Spring equinox in 2039.
EXPERIMENTAL ASTRONOMY
(2022)
Article
Geosciences, Multidisciplinary
Ralph D. Lorenz
Summary: Saltation modeling by Comola et al. (2022) suggests smaller sand size and frequent sand transport on Titan, contradicting previous assumptions. The upcoming Dragonfly mission can test these predictions.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Multidisciplinary Sciences
S. Maurice, B. Chide, N. Murdoch, R. D. Lorenz, D. Mimoun, R. C. Wiens, A. Stott, X. Jacob, T. Bertrand, F. Montmessin, N. L. Lanza, C. Alvarez-Llamas, S. M. Angel, M. Aung, J. Balaram, O. Beyssac, A. Cousin, G. Delory, O. Forni, T. Fouchet, O. Gasnault, H. Grip, M. Hecht, J. Hoffman, J. Laserna, J. Lasue, J. Maki, J. McClean, P. -y. Meslin, S. Le Mouelic, A. Munguira, C. E. Newman, J. A. Rodriguez Manfredi, J. Moros, A. Ollila, P. Pilleri, S. Schroder, M. de la Torre Juarez, T. Tzanetos, K. M. Stack, K. Farley, K. Williford
Summary: The acoustic environment on Mars was unknown before the Perseverance rover landing. This study presents the first characterization of the acoustic environment on Mars using Perseverance microphone recordings, providing important data for atmospheric studies.
Article
Astronomy & Astrophysics
Ralph D. Lorenz
Summary: This paper presents simple discrete and continuous gust models for the lower atmosphere of Titan to verify the design of the Dragonfly rotorcraft. The existing models for terrestrial airworthiness certification, which are essentially empirical, cannot be directly applied due to the different properties of Titan's atmosphere. The origins of terrestrial specifications are reviewed, and the relevant parameters are scaled using first-principles physics. A discrete 'random-walk' turbulence formulation is introduced, providing a simple implementation for numerical flight simulations and applicability to other missions.
PLANETARY AND SPACE SCIENCE
(2022)
Article
Astronomy & Astrophysics
Jason J. Benkoski, Timothy J. Montalbano, William L. Luedeman, John O. Teehan, Ralph D. Lorenz
Summary: The factors controlling dust particle adhesion are crucial for camera system design on the Moon, Mars, asteroids, and Titan. Previous experiments found that maximizing window surface electrical conductivity and minimizing surface energy can reduce adhesion of Titan dust simulants to camera windows. In this study, the effects of airflow velocity on dust adhesion were tested using sapphire windows coated with indium tin oxide and treated with fluorosilane. Results showed that dust adhesion was highest within a narrow range of airflow velocities centered at 0.11 m/s. The presence of large particles above 0.16 m/s prevented the adhesion of medium-sized particles, while particles larger than 200 μm were generally too heavy to adhere to the window at any velocity.
PLANETARY AND SPACE SCIENCE
(2023)
Article
Geochemistry & Geophysics
M. T. Lemmon, R. D. Lorenz, J. Rabinovitch, C. E. Newman, N. R. Williams, R. Sullivan, M. P. Golombek, J. F. Bell III, J. N. Maki, A. Vicente-Retortillo
Summary: Martian atmospheric dust plays a crucial role in shaping the weather on Mars, with wind-driven mobilization of surface dust being a complex and little-understood process. This study utilized video footage from helicopter flights to measure dust lifting at different altitudes and flight stages.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2022)
Article
Geochemistry & Geophysics
D. Viudez-Moreiras, M. de la Torre, J. Gomez-Elvira, R. D. Lorenz, V Apestigue, S. Guzewich, M. Mischna, R. Sullivan, K. Herkenhoff, D. Toledo, M. Lemmon, M. Smith, C. E. Newman, A. Sanchez-Lavega, J. A. Rodriguez-Manfredi, M. Richardson, R. Hueso, A. M. Harri, L. Tamppari, I Arruego, J. Bell
Summary: Wind speeds measured in Jezero crater by the Mars 2020 Perseverance rover were found to be generally calmer than in previous landing sites, despite intense aeolian activity. However, variations in wind speed were heavily influenced by turbulence and wave activity, rather than local, regional, or large-scale circulation. The power spectral density of wind speed fluctuations followed a power-law, but the slope deviated depending on the time of day. Daytime fluctuations were related to convection cells and smaller eddies in the boundary layer, while nighttime fluctuations suggested strong mechanical turbulence. Convective vortices played a role in rapid wind fluctuations and extreme winds.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2022)
Article
Engineering, Aerospace
Ralph D. Lorenz, Gary A. Allen Jr
Summary: This article presents previously-unpublished data from the Pioneer Venus multiprobe mission, documenting key events in the entry and descent process. The data includes the latter part of the hypersonic entry, deceleration through the transonic region, and parachute deployment. The comparison with the DAVINCI mission and other missions' parachute deployment records provides insights into the sample rate required to characterize key events.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Astronomy & Astrophysics
Ralph D. Lorenz, Sylvestre Maurice, Baptiste Chide, David Mimoun, Alexander Stott, Naomi Murdoch, Martin Giller, Xavier Jacob, Roger C. Wiens, Franck Montmessin, Havard Grip, Theodore Tzanetos, Bob Balaram, Nathan Williams, Matt Keennon, Sara Langberg, Jeremy Tyler, Tanguy Bertrand, Adrian Brown, Nicolas Randazzo, Benjamin Pipenberg
Summary: The sounds of the Ingenuity Helicopter flying in the Martian atmosphere were recorded by the microphone on the SuperCam instrument. The recorded audio signals show distinct frequencies at 84 Hz and occasionally at 168 Hz, corresponding to the blade crossing frequency and its first harmonic. The sound recordings also exhibit a deep modulation with nulls spaced by around 15-20s, in addition to the expected decline in amplitude with distance.
PLANETARY AND SPACE SCIENCE
(2023)
Article
Geochemistry & Geophysics
Alexander E. Stott, Naomi Murdoch, Martin Gillier, Don Banfield, Tanguy Bertrand, Baptiste Chide, Manuel De la Torre Juarez, Ricardo Hueso, Ralph Lorenz, German Martinez, Asier Munguira, Luis Mora Sotomayor, Sara Navarro, Claire Newman, Paolo Pilleri, Jorge Pla-Garcia, Jose Antonio Rodriguez-Manfredi, Agustin Sanchez-Lavega, Michael Smith, Daniel Viudez Moreiras, Nathan Williams, Sylvestre Maurice, Roger C. Wiens, David Mimoun
Summary: We use SuperCam's Mars microphone to provide information on high-frequency wind speed and turbulence on Mars. We demonstrate the sensitivity of the microphone signal level to wind speed and establish a power law dependence. A calibration function is developed using Gaussian process regression, which takes the microphone signal and air temperature as inputs to estimate the wind speed. This enables us to analyze the fast fluctuations and turbulent behavior of the wind on Mars.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2023)
Article
Astronomy & Astrophysics
Ralph Lorenz
Summary: This paper reviews topographic slopes on Titan. Cassini radar provides information on large scale slopes, while Arecibo and Cassini radar scattering properties provide information on wavelength scale slopes. The slopes on Titan are shallower compared to terrestrial planets and the Moon. The overall slope statistics suggest a fractal Hurst exponent of -0.5, but deviations may exist at dune and gravel scales. The design requirements for the Dragonfly lander and other missions are contextualized by comparing the slope tolerance of previous planetary lander missions with terrestrial rotorcraft specifications.
PLANETARY AND SPACE SCIENCE
(2023)
Article
Geochemistry & Geophysics
Keisuke Onodera, Kiwamu Nishida, Taichi Kawamura, Naomi Murdoch, Melanie Drilleau, Ryoji Otsuka, Ralph Lorenz, Anna Horleston, Rudolf Widmer-Schnidrig, Martin Schimmel, Sebastien Rodriguez, Sebastian Carrasco, Satoshi Tanaka, Clement Perrin, Philippe Lognonne, Aymeric Spiga, Don Banfield, Mark Panning, William Bruce Banerdt
Summary: Convective vortices and dust devils are common phenomena on Mars that reflect the atmospheric structure and drive the dust cycle. Investigating these vortices can improve our understanding of the Martian atmosphere and subsurface properties. NASA's InSight was used to study the vortices with meteorological and seismic data, resulting in a catalog of parameters to characterize their structure and subsurface properties. The study found that most vortices move with a tilted wall in the advection direction and that the subsurface structure can be modeled with two layers transitioning at depths of 5-15 meters.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2023)
Editorial Material
Geochemistry & Geophysics
Ralph D. Lorenz
Summary: Observations using sensitive photodiode detectors, along with movie recordings of the Ingenuity helicopter's downwash impingement, provide new insights into the dust-lifting phenomenon on Mars, revealing that particle motion and darkening can be caused by lower aerodynamic pressures than previously thought.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2023)
Article
Astronomy & Astrophysics
Aadvik S. Vashist, Michael F. Heslar, Jason W. Barnes, Corbin Hennen, Ralph D. Lorenz
Summary: We document the evolution of the north-south asymmetry (NSA) of Titan's haze albedo during the Cassini mission. Over half of a Titan year, we observe a near-complete transition in the NSA boundary latitude across the geographic equator from the southern to the northern hemisphere. Comparison of NSA images taken at similar times but different phase angles shows the NSA boundary is detectable, albeit with less contrast, at moderately high phase angles.
PLANETARY SCIENCE JOURNAL
(2023)
Article
Astronomy & Astrophysics
Lea E. Bonnefoy, Antoine Lucas, Alexander G. Hayes, Sebastien Rodriguez, Valerio Poggiali, Daniel E. Lalich, Ralph D. Lorenz, Alice Le Gall
Summary: This study utilizes radar imaging data from the Cassini spacecraft to map the Selk crater region on Titan. The results reveal variations in surface properties, indicating the exposure and fracturing of low-loss tangent materials, such as water-ice bedrock, due to impacts. The dunes and dark terrains are composed of smooth, uniform material with low dielectric constant, likely organic sand. This research provides valuable insights into the composition and geological history of Titan's surface.
PLANETARY SCIENCE JOURNAL
(2022)