Marwane Mokhtari, Bernard Bourdon
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2025.116801]
Laboratoire de Géologie de Lyon, Terre Planètes Environnement, ENS de Lyon, CNRS, Université Lyon 1. 46 Allée d’Italie, 69007 Lyon, France
Copyright Elsevier
Recent astronomical observations have shown that dust can get locally concentrated in protoplanetary disks, forming ring structures. The thermal processing of such regions could lead to dust evaporation and local enrichment of the solar gas in condensable elements. Previous studies focusing on major element behavior have shown that condensation of such dust-enriched gas could lead to the formation of a silicate melt with compositions resembling that of chondrules. However, previous studies focusing on dust-enriched environments were restricted to a limited set of elements. To study the mineralogical and chemical composition of condensates in these conditions, we have performed equilibrium calculations using the FactSage™ software for a dust-enriched solar gas. The calculations were done with dust-enrichment factors of 1 (solar composition), 10 and 100 at pressures ranging from 10−6 bar to 10−3 bar, for a CI-chondrite dust and a H-chondrite dust. The trace element condensation was accurately modelled with newly calculated activity coefficients in different solid and melt solutions. The available gas phase database was completed with new trace element species that are important to consider in oxidized conditions. The mineralogical sequence, melt composition and condensation temperature for all condensable elements were then quantified.
Our calculations show that the iron contents of olivine in equilibrium with a gas that is x100 enriched in CI-dust is consistent with that of amoeboid olivine aggregates and chondrules. Furthermore, our estimated temperature at which fayalite can form in these conditions is higher than what was previously proposed, enabling diffusion and homogenization of iron in olivine. The calculated composition of refractory metals for a x10 and x100 CI-dust enriched gas at 10−4 bar is consistent with the measured compositions of refractory metal nuggets. The possibility for these grains to have fractionated in an H2O ice-enriched gas can be ruled out as the calculated fractionation patterns in this case did not match the observed compositions.
Day: September 16, 2025
Trends in planetary science research in the Puna and Atacama Desert regions: Underrepresentation of local scientific institutions?
1A. Tavernier,2,3G. A. Pinto,4,5,6M. Valenzuela,1A. Garcia,1C. Ulloa,7R. Oses,8,9,10,11B. H. Foing
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13972]
1Instituto de Investigaciones Científicas y Tecnológicas, IDICTEC, Laboratorio de Investigacion de la Criosfera y Aguas, Universidad de Atacama, UDA, Copiapó, Chile
2Instituto de Investigación en Astronomía y Ciencias Planetarias, INCT, Universidad de Atacama, UDA, Copiapó, Chile
3Centre de Recherches Pétrographiques et Géochimiques, CRPG, Université de Lorraine, Nancy, France
4Departamento de Ciencias Geológicas, Universidad Católica del Norte, UCN, Antofagasta, Chile
5Millennium Institute of Astrophysics, MAS, Santiago, Chile
6Center for Excellence in Astrophysics and Associated Technologies, CATA, Santiago, Chile
7Centro Regional de Investigacion y Desarrollo Sustentable de Atacama, CRIDESAT, Universidad de Atacama, UDA, Copiapó, Chile
8Instituto de Investigación en Astronomía y Ciencias Planetarias, INCT, Universidad de Atacama, UDA, Copiapó, Chile
9International Lunar Exploration Working Group, ILEWG, EuroMoonMars, Noordwijk, The Netherlands
10Vrije Universiteit Amsterdam, VUA, Amsterdam, The Netherlands
11Universiteit Leiden, Leiden, The Netherlands
Published by arrangement with John Wiley & Sons
In 2019, while launching a multidisciplinary research project aimed at developing the Puna de Atacama region as a natural laboratory, investigators at the University of Atacama (Chile) conducted a bibliographic search identifying previously studied geographic points of the region and of potential interest for planetary science and astrobiology research. This preliminary work highlighted a significant absence of local institutional involvement in international publications. In light of this, a follow-up study was conducted to confirm or refute these first impressions, by comparing the search in two bibliographic databases: Web of Science and Scopus. The results show that almost 60% of the publications based directly on data from the Puna, the Altiplano, or the Atacama Desert with objectives related to planetary science or astrobiology do not include any local institutional partner (Argentina, Bolivia, Chile, and Peru). Indeed, and beyond the ethical questioning of international collaborations, Latin-American planetary science deserves a strategic structuring, networking, as well as a road map at national and continental scales, not only to enhance research, development, and innovation, but also to protect an exceptional natural heritage sampling extreme environmental niches on Earth. Examples of successful international collaborations such as the field of meteorites, terrestrial analogs, and space exploration in Chile or astrobiology in Mexico are given as illustrations and possible directions to follow to develop planetary science in South America. To promote appropriate scientific practices involving local researchers, possible responses at academic and institutional levels will eventually be discussed.
A comprehensive study of comet 67P/Churyumov-Gerasimenko in the 2021/2022 apparition. I. Photometry, spectroscopy, morphology
Vera Rosenbusha,b, et al. (>5)
Icarus (in Press) Open Access Link to Article [https://doi.org/10.1016/j.icarus.2025.116799]
aAstronomical Observatory of Taras Shevchenko National University of Kyiv, 3 Observatorna St., Kyiv 04053, Ukraine
Copyright Elsevier
We present observations of comet 67P/Churyumov–Gerasimenko during its 2021/22 apparition, aiming to investigate its dust and gas environment and compare the results with those obtained in 2015/16 using the same telescope. Quasi-simultaneous photometric, spectroscopic, and polarimetric observations were carried out at the 6-m BTA SAO telescope. The comet was observed on 6 October 2021, 31 days before perihelion, with g-sdss and r-sdss filters, and on 6 February 2022, 96 days after perihelion, using narrowband cometary filters: BC (λ4450/62 Å), RC (λ6839/96 Å), and CN(λ3870/58 Å). These were complemented by images from the 2-m Liverpool Telescope (La Palma). On 6 October 2021, a sunward jet and long dust tail were detected. By 6 February 2022, the dust coma morphology had changed noticeably, revealing a bright sunward neckline structure superimposed on the projected dust tail, along with two jets at position angles of 133° and 193°. Spectra showed strong CN emission, with relatively weak C₂, C₃, and NH₂ emissions. The dust production rate Afρ did not exceed 200 cm (uncorrected for phase angle) in both epochs. An unusual CN coma morphology was observed, with evidence of an additional CN source associated with dust jets. Geometric modeling of the jets’ dynamics indicated an active area at latitude −70° ± 4° with a jet opening angle of 20° ± 6° on 6 October 2021, and two active areas at latitudes −58° ± 5° and − 53° ± 10°, separated by longitude 150° ± 20°, producing the observed jets on 6 February 2022. The average particle velocity in the jets was about 0.32 ± 0.04 km s−1.
The YORP effect for meter-sized asteroids
Conor J. Benson, Daniel J. Scheeres
Icarus (in Press) Open Access Link to Article [https://doi.org/10.1016/j.icarus.2025.116794]
University of Colorado Boulder, 3775 Discovery Drive, Boulder, CO 80303, USA
Copyright Elsevier
The spin states of meter-sized asteroids should evolve rapidly due to the Yarkovsky-O’Keefe-Radzievskii-Paddack (YORP) effect. While these asteroids are very challenging to observe, artificial geosynchronous (GEO) satellites are convenient analogues given that they are driven primarily by solar torques, evolve rapidly, and are easy to observe. These artificial objects could provide insight about the evolution of their natural counterparts. Recent studies of YORP for defunct GEO satellites with full and tumbling-averaged models have uncovered rich dynamical structure with tumbling cycles, angular momentum sun-tracking, and tumbling resonances. Applying the tumbling-averaged YORP models to meter-sized pseudo asteroids, we find that the solar torque structure yields sun-tracking precession in many cases, particularly for asteroids with at least some elongation. Precession about the sun line results in the long-term obliquity averaging to roughly 90°. As a result, the sun-tracking behavior could potentially shut off Yarkovsky drift for these asteroids and thereby limit their mobility out of the main asteroid belt. For some asteroid shapes, tumbling cycles with alternating spin up and spin down are also observed. These tumbling cycles offer a possible avenue to prevent spin-driven disruption of meteoroids.
Cosmochemistry Papers 