Article
Astronomy & Astrophysics
J. A. Sinclair, C. M. Lisse, G. S. Orton, M. Krishnamoorthy, L. N. Fletcher, J. Hora, C. Palotai, T. Hayward
Summary: We retrospectively analyzed Earth-based mid-infrared observations of Jupiter after its impacts by SL9 in July 1994 and the Wesley impactor in July 2009, using consistent data reduction and analysis methods. The SL9 impacts resulted in enhanced CH4 emissions at 7.9 μm and NH3 emissions at 8.5-11.5 μm, while the Wesley impact exhibited enhanced emissions at 8.8-11.5 μm and 18-19 μm. The different composition and altitude of the impacts indicate deeper penetration for SL9, with NH3 abundances about 40 times higher than in the Wesley impact. The absence of silicates in the Wesley impact suggests a different incident angle and entry angle for the impactor.
Review
Astronomy & Astrophysics
Dennis Bodewits, Zexi Xing, Mohammad Saki, Jeffrey P. P. Morgenthaler
Summary: The Neil-Gehrels Swift Observatory has significantly contributed to our understanding of small bodies in our solar system. Its rapid response and tracking capabilities have enabled important studies on the water sources in comets, changes in the rotation period of comets, and the properties of asteroids over time through near-UV spectroscopic observations.
News Item
Multidisciplinary Sciences
Alexandra Witze
Summary: Despite the disruption caused by the pandemic, astronomers detected thousands of previously unknown near-Earth asteroids last year.
Article
Astronomy & Astrophysics
Andrew C. Roberts, Marco A. Munoz-Gutierrez
Summary: The dynamics of small bodies in the near Centaur region (NCR) were examined, revealing their short lifetimes and quick passage through the region. Resonant behavior was found to be common in this area, trapping objects for up to 100 Kyr. Limits on the reservoir size of Neptune crossers were determined through simulations, ultimately providing constraints on the population of Centaurs and the NCR population.
Article
Astronomy & Astrophysics
Pawel Kankiewicz, Ireneusz Wlodarczyk
Summary: The dynamical studies of retrograde asteroid populations with various non-gravitational force models provide insight into the stability of retrograde bodies. The Yarkovsky effect and cometary effects play significant roles in influencing the stability of retrograde bodies, while retrograde resonances are confirmed to be involved in the process. The use of models with non-gravitational effects for retrograde bodies is justified based on the results obtained.
ASTRONOMY & ASTROPHYSICS
(2021)
News Item
Multidisciplinary Sciences
Alexandra Witze
Summary: Samples collected by NASA's OSIRIS-REx mission have the potential to reveal secrets of the Solar System.
News Item
Multidisciplinary Sciences
Alexandra Witze
Summary: The mysterious space rock, possibly the exposed core of a planet that failed to fully form, could provide insights into the origins of the Solar System.
Article
Astronomy & Astrophysics
Eloy Pena-Asensio, Josep M. Trigo-Rodriguez, Albert Rimola
Summary: There is a continuous influx of extraterrestrial materials into the Earth's atmosphere, with some objects producing luminous columns upon encountering air molecules. By studying NASA's fireball database, we were able to infer the dynamic origin of large bolides produced by meter-sized projectiles that hit the Earth. Our findings suggest that a significant fraction of these impactors may have asteroidal or cometary origins, and that interstellar meter-sized meteoroids could be more common than previously thought.
ASTRONOMICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Aster G. Taylor, Davide Farnocchia, David Vokrouhlicky, Darryl Z. Seligman, Jordan K. Stecklofff, Marco Micheli
Summary: Significant nonradial and nongravitational accelerations, which cannot be explained by radiation-driven effects, have been observed in seven photometrically inactive near-Earth objects. The study proposes that these accelerations can be explained by anisotropic outgassing resulting from differential heating on the nucleus of these objects. This explanation, although lacking confirmation of spin axes, provides a plausible mechanism for the observed accelerations and accurately perturbs the heliocentric motions of most of these objects.
Article
Astronomy & Astrophysics
A. Dell'Oro, J. Boccenti, F. Spoto, P. Paolicchi, Z. Knezevic
Summary: This paper discusses methods for estimating the ages of asteroid families, and explores mechanisms that can affect these methods, such as initial velocity distribution, correlations between ejection direction and rotational axis orientation, gravitational reaccumulation, and collisional reorientation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Editorial Material
Multidisciplinary Sciences
Marco Micheli
Summary: A simple and physically realistic model is proposed to reconcile the seemingly contradictory observations of the first known interstellar object, providing an understanding of its peculiarities.
Article
Astronomy & Astrophysics
Lea Ferellec, Colin Snodgrass, Alan Fitzsimmons, Agata Rozek, Daniel Gardener, Richard Smith, Hissa Medeiros, Cyrielle Opitom, Henry H. Hsieh
Summary: Main Belt Comets (MBCs) show sublimation-driven activity while orbiting in the Main Asteroid Belt. MBCs and candidates exhibit a higher concentration of perihelion longitudes around 15 degrees compared to other objects in the Outer Main Belt (OMB). This characteristic may aid in the discovery of new candidates by observing objects in similar orbits.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Josep M. Trigo-Rodriguez, Juergen Blum
Summary: Meteor physics provides new insights into cometary disintegration products, bridging various research fields. Estimations of mass distributions of meteoroids from different cometary streams help understand their characteristics.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Editorial Material
Multidisciplinary Sciences
Meenakshi Wadhwa
Summary: The safe delivery of samples from an asteroid on September 24th will commence a global scientific journey, highlighting the need for support in similar missions.
Article
Astronomy & Astrophysics
He Liang, Jianchun Shi, Yuehua Ma, Ruiqi Xu, Juncen Li
Summary: By analyzing the evolutionary patterns and activity status of four main-belt comets that do not have obvious coma and have small amplitudes, we can gain a better understanding of the activity process and decay process of these low-level active comets, and then understand the evolution of comet activity.
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.
Article
Astronomy & Astrophysics
A. Praet, G. Poggiali, M. A. Barucci, B. E. Clark, X-D Zou, A. A. Simon, H. H. Kaplan, J-Y Li, C. Alcaria
Summary: The OSIRIS-REx spacecraft successfully sampled and stored the surface of asteroid Bennu. The sampling maneuver altered the morphology of the sampling site, providing an opportunity to study the subsurface of Bennu in detail. Analysis of the infrared spectrum showed no significant variations in the near-infrared bands, but the sampling site appeared redder and possible modifications were observed in the hydrated band.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Geochemistry & Geophysics
A. Munguira, R. Hueso, A. Sanchez-Lavega, M. de la Torre-juarez, G. M. Martinez, C. E. Newman, E. Sebastian, A. Lepinette, A. Vicente-Retortillo, B. Chide, M. T. Lemmon, T. Bertrand, R. D. Lorenz, D. Banfield, J. Gomez-Elvira, J. Martin-Soler, S. Navarro, J. Pla-Garcia, J. A. Rodriguez-Manfredi, J. Romeral, M. D. Smith, J. Torres
Summary: The Mars Environmental Dynamics Analyzer instrument on Mars 2020 records temperature changes in Jezero, showing convective regime during the daytime and stable atmosphere at night with peak temperature fluctuations of 2.5K. The thermal inertia of the terrain affects surface temperatures and breaks the nighttime thermal inversion over terrains with high thermal inertia. Possible detections of thermal tides and atmospheric waves in near-surface temperatures are investigated, and the response of the surface and atmosphere during a regional dust storm is analyzed.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2023)
Article
Geochemistry & Geophysics
J. Polkko, M. Hieta, A. -M. Harri, L. Tamppari, G. Martinez, D. Viudez-Moreiras, H. Savijarvi, P. Conrad, M. P. Zorzano Mier, M. De La Torre Juarez, R. Hueso, A. Munguira, J. Leino, F. Gomez, I. Jaakonaho, E. Fischer, M. Genzer, V. Apestigue, I. Arruego, D. Banfield, A. Lepinette, M. Paton, J. A. Rodriguez-Manfredi, A. Sanchez Lavega, E. Sebastian, D. Toledo, A. Vicente-Retortillo
Summary: The Mars 2020 mission rover Perseverance, launched on 30 July 2020 by NASA, successfully landed on 18 February 2021 at Jezero Crater, Mars. The payload of Perseverance includes the MEDA HS sensor, which measures relative humidity on Mars. The observations from sol 80 to sol 410 show that the measured humidity is reliable during the late night hours and few tens of minutes after sunrise when it is greater than 2%. Data delivered include relative humidity, sensor temperature, uncertainty, and volume mixing ratio.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2023)
Article
Geochemistry & Geophysics
R. Hueso, C. E. Newman, T. del Rio-Gaztelurrutia, A. Munguira, A. Sanchez-Lavega, D. Toledo, V. Apestigue, I. Arruego, A. Vicente-Retortillo, G. Martinez, M. Lemmon, R. Lorenz, M. Richardson, D. Viudez-Moreiras, M. de la Torre-juarez, J. A. Rodriguez-Manfredi, L. K. Tamppari, N. Murdoch, S. Navarro-Lopez, J. Gomez-Elvira, M. Baker, J. Pla-Garcia, A. M. Harri, M. Hieta, M. Genzer, J. Polkko, I. Jaakonaho, T. Makinen, A. Stott, D. Mimoun, B. Chide, E. Sebastian, D. Banfield, A. Lepinette-Malvite
Summary: We characterized vortex and dust devils at Jezero using data from the Mars Environmental Dynamics Analyzer (MEDA) instrument on Mars 2020. We found that vortices are abundant, with a peak at noon. At least one in every five vortices carries dust, and 75% of vortices with a pressure drop greater than 2.0 Pa are dusty. Vortices are more frequent and intense over terrains with lower thermal inertia.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2023)
Article
Geochemistry & Geophysics
D. Toledo, V. Apestigue, I. Arruego, M. Lemmon, L. Gomez, F. Montoro, R. Hueso, C. Newman, M. Smith, D. Viudez-Moreiras, G. Martinez, R. Lorenz, A. Vicente-Retortillo, A. Sanchez-Lavega, M. de la Torre Juarez, J. A. Rodriguez-Manfredi, I. Carrasco, M. Yela, J. J. Jimenez, E. Garcia-Menendez, S. Navarro, F. J. Gomez-Elvira, A. -M. Harri, J. Polkko, M. Hieta, M. Genzer, N. Murdoch, E. Sebastian
Summary: The Mars Environmental Dynamics Analyzer onboard the Perseverance rover is a meteorological station that detected 374 dust devils on Mars. The study estimated the frequency of dust devil formation and analyzed their diameter, height, and trajectory. The findings also revealed the impact of dust devils on UV irradiance.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2023)
Article
Geochemistry & Geophysics
G. M. Martinez, E. Sebastian, A. Vicente-Retortillo, M. D. Smith, J. R. Johnson, E. Fischer, H. Savijarvi, D. Toledo, R. Hueso, L. Mora-Sotomayor, H. Gillespie, A. Munguira, A. Sanchez-Lavega, M. T. Lemmon, F. Gomez, J. Polkko, L. Mandon, V. Apestigue, I. Arruego, M. Ramos, P. Conrad, C. E. Newman, M. de la Torre-Juarez, F. Jordan, L. K. Tamppari, T. H. McConnochie, A. -M. Harri, M. Genzer, M. Hieta, M. -P. Zorzano, M. Siegler, O. Prieto, A. Molina, J. A. Rodriguez-Manfredi
Summary: The Mars Environmental Dynamics Analyzer (MEDA) on board Perseverance includes first-of-its-kind sensors to measure various radiation fluxes on Mars surface. Using these measurements and ground temperature data, the study determines the radiative budget and broadband albedo of Mars, as well as calculates the thermal inertia of homogeneous terrains. The study also compares the results with other measurements to validate model predictions and provide ground-truth data.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2023)
Article
Astronomy & Astrophysics
James S. D. Blake, L. N. Fletcher, G. S. Orton, A. Antunano, M. T. Roman, Y. Kasaba, T. Fujiyoshi, H. Melin, D. Bardet, J. A. Sinclair, M. Es-Sayeh
Summary: Ground-based mid-infrared images of Saturn over a multi-decade period reveal seasonal and non-seasonal variability in thermal emission. 8-m class observatories can resolve thermal contrasts on various scales and confirm the consistency of Saturn's thermal structure from year to year. However, inter-annual variations are observed in the equatorial banding, suggesting the influence of tropospheric meteorology.
Review
Astronomy & Astrophysics
Leigh N. Fletcher, Thibault Cavalie, Davide Grassi, Ricardo Hueso, Luisa M. Lara, Yohai Kaspi, Eli Galanti, Thomas K. Greathouse, Philippa M. Molyneux, Marina Galand, Claire Vallat, Olivier Witasse, Rosario Lorente, Paul Hartogh, Francois Poulet, Yves Langevin, Pasquale Palumbo, G. Randall Gladstone, Kurt D. Retherford, Michele K. Dougherty, Jan-Erik Wahlund, Stas Barabash, Luciano Iess, Lorenzo Bruzzone, Hauke Hussmann, Leonid I. Gurvits, Ondrej Santolik, Ivana Kolmasova, Georg Fischer, Ingo Mueller-Wodarg, Giuseppe Piccioni, Thierry Fouchet, Jean-Claude Gerard, Agustin Sanchez-Lavega, Patrick G. J. Irwin, Denis Grodent, Francesca Altieri, Alessandro Mura, Pierre Drossart, Josh Kammer, Rohini Giles, Stephanie Cazaux, Geraint Jones, Maria Smirnova, Emmanuel Lellouch, Alexander S. Medvedev, Raphael Moreno, Ladislav Rezac, Athena Coustenis, Marc Costa
Summary: ESA's Jupiter Icy Moons Explorer (JUICE) will conduct a detailed investigation of the Jovian system in the 2030s, utilizing state-of-the-art instruments and a tailored orbital tour. The mission aims to gather information on the climate, meteorology, and chemistry of Jupiter's atmosphere and auroras, as well as studying phenomena on various timescales. The remote sensing payload includes spectroscopy, imaging, and sounding techniques, allowing for a comprehensive characterization of the planet's atmosphere and auroras.
SPACE SCIENCE REVIEWS
(2023)
Article
Multidisciplinary Sciences
Samantha K. K. Trumbo, Michael E. E. Brown, Dominique Bockelee-Morvan, Imke de Pater, Thierry Fouchet, Michael H. H. Wong, Stephanie Cazaux, Leigh N. Fletcher, Katherine de Kleer, Emmanuel Lellouch, Alessandro Mura, Olivier Poch, Eric Quirico, Pablo Rodriguez-Ovalle, Mark R. R. Showalter, Matthew S. S. Tiscareno, Federico Tosi
Summary: Ganymede, the only satellite with an intrinsic magnetic field, experiences interactions with the Jovian magnetosphere, resulting in the accumulation of charged particles in its polar regions. Observations with JWST have revealed the presence of hydrogen peroxide, a product of radiolysis, at high latitudes, indicating the modification of polar caps by precipitation of Jovian charged particles along partially open field lines within Ganymede's magnetosphere. This discovery, along with the contrasting distribution of hydrogen peroxide on Europa, has important implications for understanding water-ice radiolysis in the solar system.
Article
Astronomy & Astrophysics
Ricardo Hueso, Agustin Sanchez-Lavega, Thierry Fouchet, Imke de Pater, Arrate Antunano, Leigh N. Fletcher, Michael H. Wong, Pablo Rodriguez-Ovalle, Lawrence A. Sromovsky, Patrick M. Fry, Glenn S. Orton, Sandrine Guerlet, Patrick G. J. Irwin, Emmanuel Lellouch, Jake Harkett, Katherine de Kleer, Henrik Melin, Vincent Hue, Amy A. Simon, Statia Luszcz-Cook, Kunio M. Sayanagi
Summary: Observations from the James Webb Space Telescope reveal the presence of a strong equatorial jet in Jupiter's atmosphere, with a velocity of 140 m/s and confined within +/- 3 degrees of the equator.
Article
Astronomy & Astrophysics
Brandon Park Coy, Conor A. Nixon, Naomi Rowe-Gurney, Richard Achterberg, Nicholas A. Lombardo, Leigh N. Fletcher, Patrick Irwin
Summary: This work presents the first infrared spectra of Titan obtained from the Spitzer Space Telescope. The data includes emissions of various molecules such as CH4, C2H2, C2H4, C2H6, C3H4, C3H6, C3H8, C4H2, HCN, HC3N, and CO2. Comparisons with the Cassini Composite Infrared Spectrometer (CIRS) reveal discrepancies in the observations, suggesting the need for further analysis.
PLANETARY SCIENCE JOURNAL
(2023)
Review
Astronomy & Astrophysics
Christopher R. Webster, Amy E. Hofmann, Paul R. Mahaffy, Sushil K. Atreya, Christopher H. House, Amy A. Simon, James B. Garvin
Summary: Distinguishing planetary formation and evolution pathways and understanding the origins of volatiles on planetary bodies can be achieved by accurately measuring the relative abundances and isotope ratios in noble gases, as well as the isotope ratios in C, H, N, O and S. Traditional planetary mass spectrometers provide excellent survey capability, while tunable laser spectrometers (TLS) can achieve high precision measurements of isotope ratios in C and O to distinguish planetary evolution models. TLS instruments are capable of detecting a wide variety of gases at parts-per-billion levels and can achieve isotope ratio measurements at precisions of similar to 1-2 parts per thousand for C, H, N, O and S molecules.
SPACE SCIENCE REVIEWS
(2023)
Article
Geochemistry & Geophysics
P. G. J. Irwin, J. Dobinson, A. James, M. H. Wong, L. N. Fletcher, M. T. Roman, N. A. Teanby, D. Toledo, G. S. Orton, S. Perez-Hoyos, A. Sanchez-Lavega, A. Simon, R. Morales-Juberias, I. de Pater
Summary: Spectral observations of Neptune in 2019 reveal spatial variations in aerosol scattering properties and methane abundance in the planet's atmosphere. The darkening of certain features in the atmosphere is due to spectrally dependent darkening of particles in a deep aerosol layer, while bright zones at longer wavelengths are attributed to brightening of particles in the same aerosol layer. The properties of an upper methane/haze aerosol layer remain constant with latitude, and variations in an upper tropospheric haze layer account for changes in reflectivity at methane-absorbing wavelengths.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2023)
Article
Astronomy & Astrophysics
Maria Angeles Lopez-Cayuela, Maria-Paz Zorzano, Juan Luis Guerrero-Rascado, Carmen Cordoba-Jabonero
Summary: The atmospheric dust cycle on Mars plays a dominant role in the planetary radiative balance, atmospheric photochemistry escape, and redistribution of materials on the surface. A methodology is presented to accurately describe the annual dust redistribution cycle on Mars using orbital global and seasonal measurements of atmospheric dust opacity. The analysis shows that approximately 4 trillion kilograms of dust is transported globally in the atmosphere during a typical Mars year.
Article
Astronomy & Astrophysics
Audrey Vorburger, Shahab Fatemi, Shane R. Carberry Mogan, Andre Galli, Lucas Liuzzo, Andrew R. Poppe, Lorenz Roth, Peter Wurz
Summary: The study presents new model results for the composition of Ganymede's atmosphere, finding that sublimation remains the major source process for H2O, while radiolysis induced by auroral electrons dominates the source fluxes for O2 and H2.
Article
Astronomy & Astrophysics
Qi He, Zhi Cao, Yuqi Qian, Hejiu Hui, Ioannis Baziotis, Long Xiao, Zaicong Wang, Biji Luo, Yiheng Li, Zongjun Ying, Yang Li
Summary: The Chang'e-5 mission collected lunar soil containing magnesian troctolitic granulites, which provide valuable information on the composition of the lunar crust. Through analysis and modeling, it is suggested that these granulites may have originated from the Pythagoras crater and were transported to the landing site.
Article
Astronomy & Astrophysics
Jordan M. Bretzfelder, Kathryn M. Stack, Abigail A. Fraeman, Mackenzie Day, William E. Dietrich, Alexander B. Bryk
Summary: This study investigates the development of bedrock ridges on Mars and their implications for wind history, deposition, and erosion in Gale crater.
Article
Astronomy & Astrophysics
Lot Ram, Diptiranjan Rout, Rahul Rathi, Paul Withers, Sumanta Sarkhel
Summary: This study investigates the impacts of interplanetary coronal mass ejections (ICMEs) on the Martian ionosphere, specifically the behavior of the ionospheric peak density and height during ICME passages. The study used observations from the Radio Occultation Science Experiment (ROSE) aboard the MAVEN spacecraft and selected 8 ICMEs from existing catalogs. The results show that ICMEs lead to an elevation of the ionospheric peak height and a decrease in peak density, and propose that vertical pressure gradient and electron temperature enhancement are plausible causes for ionospheric variability.
Article
Astronomy & Astrophysics
Benoit Jabaud, Riccardo Artoni, Gabriel Tobie, Erwan Le Menn, Patrick Richard
Summary: The Cassini spacecraft discovered active jets of water vapour and ice grains at the South Pole of Enceladus, resulting in the deposit of freshly erupted materials on the moon's icy surface. Similar processes may be happening on Europa as well. Determining the mechanical properties of fresh icy powder-like materials is essential for future landing and sampling missions. The flowability and surface energy of ice powders decrease with increasing temperatures, which may have implications for stable landing and the flow of ice materials on Enceladus and Europa.
Article
Astronomy & Astrophysics
Lydie Bonal, Eric Quirico, Gilles Montagnac, Mutsumi Komatsu, Yoko Kebukawa, Hikaru Yabuta, Kana Amano, Jens Barosch, Laure Bejach, George D. Cody, Emmanuel Dartois, Alexandre Dazzi, Bradley De Gregorio, Ariane Deniset-Besseau, Jean Duprat, Cecile Engrand, Minako Hashiguchi, Kanami Kamide, David Kilcoyne, Zita Martins, Jeremie Mathurin, Smail Mostefaoui, Larry Nittler, Takuji Ohigashi, Taiga Okumura, Laurent Remusat, Scott Sandford, Miho Shigenaka, Rhonda Stroud, Hiroki Suga, Yoshio Takahashi, Yasuo Takeichi, Yusuke Tamenori, Maximilien Verdier-Paoletti, Shohei Yamashita, Tomoki Nakamura, Hiroshi Naraoka, Takaaki Noguchi, Ryuji Okazaki, Hisayoshi Yurimoto, Shogo Tachibana, Masanao Abe, Akiko Miyazaki, Aiko Nakato, Satoru Nakazawa, Masahiro Nishimura, Tatsuaki Okada, Takanao Saiki, Kanako Sakamoto, Satoshi Tanaka, Fuyuto Terui, Yuichi Tsuda, Tomohiro Usui, Sei-ichiro Watanabe, Toru Yada, Kasumi Yogata, Makota Yoshikawa
Summary: This paper focuses on characterizing the thermal history of asteroid Ryugu by studying the structure of polyaromatic carbonaceous matter in the returned samples. The study finds that there is no structural difference in the polyaromatic component between the two sampling sites on Ryugu, indicating that the thermal metamorphism related to radioactive decay was not significant. However, some structural variability is observed within the particle set.
Article
Astronomy & Astrophysics
M. Luginin, A. Fedorova, D. Belyaev, F. Montmessin, O. Korablev, J. -l. Bertaux
Summary: Spectroscopic solar occultation measurements by the SPICAV/SOIR instrument onboard the Venus Express orbiter provided new data on the upper haze aerosol properties, its distribution, and variations. A joint analysis of data from two spectrometers revealed a bimodal distribution in about 50% of observations previously believed to be unimodal, and characterized the size distribution 10 km higher in the atmosphere compared to previous analysis.
Article
Astronomy & Astrophysics
A. Mahieux, S. Viscardy, K. L. Jessup, F. P. Mills, L. Trompet, S. Robert, S. Aoki, A. Piccialli, A. C. Vandaele
Summary: We report on the mean upper limit number densities and volume concentrations of H2CO, O-3, NH3, HCN, N2O, NO2, NO, and HO2 at the Venus terminator above the cloud layer. Attempts to detect these species using a statistical algorithm and the method presented by Trompet et al. (2021) were unsuccessful, and upper limits of detection are provided.
Article
Astronomy & Astrophysics
P. M. Streeter, S. R. Lewis, M. R. Patel, J. A. Holmes, K. Rajendran
Summary: The northern polar vortex on Mars shows a high degree of interannual repeatability in its structure and evolution, except during large dust storms. The seasonal timing of these storms seems to be the key factor determining their impacts on the polar vortex.
Article
Astronomy & Astrophysics
Michael T. Mellon, Hanna G. Sizemore, Jennifer L. Heldmann, Christopher P. McKay, Carol R. Stoker
Summary: The search for life is a major focus of Mars exploration, with temperature and water activity being key factors for habitability. The most recent habitable conditions occurred about 510 kyrs ago and lasted for about 10s of kyrs each occurrence. All latitudes offer potential for life exploration, but middle-latitude sites have access to 100-kyr-old ice that experienced past habitable conditions, while high-latitude sites offer access to ancient ice over 1 Myrs old.
Article
Astronomy & Astrophysics
Anthony Ozerov, Jeffrey C. Smith, Jessie L. Dotson, Randolph S. Longenbaugh, Robert L. Morris
Summary: The Geostationary Lightning Mapper (GLM) instruments, with their large combined field of view, are useful for studying the population of atmospheric phenomena like bolides. However, there are biases when using GLM for non-lightning purposes, which need to be studied and accounted for before precise measurements of bolide flux can be obtained. A Bayesian Poisson regression model was developed to estimate instrumental biases and the latitudinal variation of bolide flux concurrently. The estimated bias corresponds to the known sensitivity of the GLM instruments, and the latitudinal flux variation estimates are consistent with a strong bias towards high-velocity bolides, as compared to existing theoretical models.
Article
Astronomy & Astrophysics
P. Beck, P. Y. Meslin, A. Fau, O. Forni, O. Gasnault, J. Lasue, A. Cousin, S. Schroeder, S. Maurice, W. Rapin, R. C. Wiens, A. M. Ollila, E. Dehouck, N. Mangold, B. Garcia, S. Schwartz, W. Goetz, N. Lanza
Summary: Analysis of data obtained by ChemCam on Mars reveals that the carbon signal is mainly related to ionization of the atmosphere, with variability potentially linked to the physical state of the atmosphere. Up to sol 3355, no carbonate was detected in the ChemCam dataset, suggesting that it is not a major constituent (>50%) in the analyzed targets and that carbon in soils is not enriched beyond the limit of detection. The dominant salts found in Gale are sulfate and chlorides, while the absence of carbonates, seen in Jezero, may be due to differences in protolith.
Article
Astronomy & Astrophysics
Eloy Pena-Asensio, Jaakko Visuri, Josep M. Trigo-Rodriguez, Hector Socas-Navarro, Maria Gritsevich, Markku Siljama, Albert Rimola
Summary: The observation of interstellar objects 1I/'Oumuamua and 2I/Borisov suggests the existence of a larger population of smaller projectiles that impact our planet with unbound orbits. A statistical evaluation of uncertainties in the CNEOS database and study of its hyperbolic fireballs reveals an anisotropic geocentric radiant distribution and low orbital inclinations, challenging the assumption of a randomly incoming interstellar population. These findings suggest that apparent interstellar meteors may, in fact, be the result of accelerated meteoroid impacts caused by close encounters with massive objects within or passing through our solar system.
Article
Astronomy & Astrophysics
Cecilia W. S. Leung, Leslie K. Tamppari, David M. Kass, German Martinez, Erik Fischer, Michael D. Smith
Summary: Using a combination of orbital and surface observations, this study investigates the vertical distribution of water vapor in the lower atmospheres of Mars. The findings suggest that the assumption of uniformly mixed water vapor in the boundary layer is not always consistent with observational constraints. The results provide important insights into the seasonal transport of water and the role of regolith-atmospheric exchange.