Saturn’s magnetism and diamagnetism of ice can help explain the emergence of visible dense rings by transformation of the protoplanetary cloud containing ice bodies into a disk-shaped system of stable visible dense rings with extreme flatness at Saturn’s equator. It can also explain the thin structure of the rings as a whole, the sharp edges of dense rings, the existence and specific features of B-rings, and the stability of the entire dense ring system around Saturn. Additionally, it allows calculation of equilibrium separation of ice bodies, as predicted by J.C. Maxwell, with the magnetic repulsion of the ice bodies compensating for their gravitational attraction.

This study analyzes the motion of bodies ejected from the Earth or the Moon. We studied the ejection of bodies from several points on the Earth’s surface, as well as from the most far point of the Moon from the Sun. Different velocities and angles of ejection of bodies were considered. The dynamical lifetimes of bodies reached a few hundred million years. Over the entire considered time interval, the values of the probability of a collision of a body ejected from the Earth with the Earth were approximately 0.3, 0.2, and 0.15–0.2 at an ejection velocity υej equaled to 11.5, 12, and 14 km/s, respectively. At υej≤11.3 km/s, most of the ejected bodies fell back onto the Earth. The total number of bodies delivered to the Earth and Venus probably did not differ much. The probabilities of collisions of bodies with Mercury and Mars usually did not exceed 0.1 and 0.02, respectively. At υej ≥11.5 km/s, the probability of a collision of a body ejected from the Earth with the Moon was about 15–35 times less than that with the Earth, and it was about 0.01. The probability of a collision with the Earth for a body ejected from the Moon moving in its present orbit was about 0.3–0.32, 0.2–0.22, and 0.1–0.14 at υej =2.5 km/s, υej =5 km/s, and at 12≤ υej ≤16.4 km/s, respectively.

The increasing addition of meteor showers to the International Astronomical Union (IAU) list underscores the need for more accurate identification of new parent bodies, especially with the growing availability of video meteor data. Current methods using a high-threshold single-linking Dsh criterion often lack accuracy, prompting our study to explore advanced techniques for linking meteors to their parent bodies. Using the Moroccan meteor observation network as a foundation, we applied and compared several methods on the SonotaCo and EDMOND databases to detect new parent bodies. We further applied rigorous statistical tests to avoid random associations. This presentation highlights the network’s innovative methodology, its success in accurately tracing meteoroid origins, and its potential to predict impact zones on Earth (Guennoun et al.(2019)). Through collaborative efforts, this network provides a significant contribution in the study of meteor dynamics.

Whether an exoplanet can retain its atmosphere is mainly controlled by the extreme-ultraviolet (EUV) radiation received from its host star, and the photo-chemistry in its outer atmosphere is driven by the far-ultraviolet radiation, primarily the hydrogen Lyman-α line, from its host star. Since interstellar hydrogen absorbs most of this EUV and Lyman-α radiation, there is a critical need for accurate reconstruction techniques to identify the intrinsic EUV and Lyman-α radiation that impacts the outer atmosphere of an exoplanet. This paper describes and critiques the available reconstruction techniques.

The motion of planetesimals was studied in the Proxima Centauri and TRAPPIST 1 exoplanetary systems. The size of the feeding zone of planet Proxima Centauri c is discussed. It was noted that after hundreds of Myrs, some planetesimals could still move in elliptical resonant orbits inside the feeding zone of this planet that had been mainly cleared from planetesimals. The probability of a collision of a planetesimal initially located in the feeding zone of planet c with inner planet b was obtained to be about 0.0002 and 0.001 at initial eccentricity of orbits of planetesimals equal to 0.02 or 0.15, respectively. A lot of icy material and volatiles could be delivered from the icy zone near the orbit of planet c to inner planets b and d. The inclinations of orbits of 80% of the planetesimals that moved between 500 or 1200 AU from the star did not exceed 10°. It was obtained that several planets in the TRAPPIST-1 system accumulated planetesimals initially located at the same distance. Outer layers of neighbouring TRAPPIST-1 planets can include similar material.

The characterisation of stellar magnetism of planetary host stars has increased momentum, especially for transmission spectroscopy investigations of exoplanets. Indeed, the magnetic field regulates how irradiated planets are, and the presence of inhomogeneities on the stellar surface hinder the precise extraction of the planetary atmospheric absorption signal. We are conducting a spectropolarimetric campaign to unveil the magnetic field properties of known exoplanet hosting stars included in the current list of Ariel targets. Here, we will focus on two of them: GJ 436 and HD 63433. The former hosts a warm-Neptune experiencing substantial atmospheric loss, modelled as a comet-like trail of hydrogen atoms. The latter hosts two sub-Neptunes and an Earth-sized planet that have likely experienced different atmospheric evolution paths. We reconstructed the stellar large-scale magnetic field via Zeeman-Doppler imaging, and used it as boundary condition to simulate the stellar magnetised wind and environment at the planetary orbits. For GJ 436, the planet motion is sub-Alfvénic, meaning that star-planet magnetic connections can occur. We derived the power released by star-planet interactions to be 1022 − 1023 erg/s, consistent with the upper limit of 1026 erg/s measured from ultraviolet lines. For HD63433, we identified 10% of the innermost planetary orbit as sub-Alfvénic, while the outer planets are outside the Alfvén surface, and a bow shock between the stellar wind and the planetary magnetosphere could form.

Liquid water can exist on exoplanets in a circumstellar region significantly wider than the Conservative Habitable Zone (CHZ). In particular, tidally locked planets orbiting closer inwards than the inner CHZ border could have liquid water on their night side provided the heat transport between the day and night side is low. Planets further away than the outer CHZ boundary can maintain subglacial liquid water if they have geothermal heat sources or in the form of subglacial lakes similar to the Martian polar lakes. Pressurized water can reach the planetary surface through faults and cracks in the ice cover, creating plumes and enriching the atmosphere with molecules that may be present in subglacial oceans. We discuss the model and the conditions needed to detect water and other molecules in the transmission spectrum by JWST, as have recently been detected in small hot exoplanets such as GJ287 b.

In this work, we compared the chemistry and emission spectra of nitrogen-dominated Ultra-Short-Period (USP) super-Earth atmospheres at various surface pressures (0.1 to 10 bar) in and out of chemical equilibrium. We used the VULCAN chemical kinetic code, which includes thermochemical kinetics, vertical transport, and photochemistry, linked with the petitRADTRANS radiative transfer model to predict emission spectra. Radiative-convective temperature-pressure profiles were computed with the HELIOS code. Using PandExo noise simulations, we explored the observability of disequilibrium effects with JWST. Our results showed that surface pressure significantly impacted temperature profiles, atmospheric abundances, and emission spectra. Disequilibrium signatures in cooler planets were detectable by targeting HCN, C2H4, and CO, while warmer planets showed CH4 and HCN features using JWST’s NIRSpec and MIRI instruments. These species also provided insights into the presence of surfaces in nitrogen-dominated atmospheres, revealing details about atmospheric thickness.

Water, an essential molecule for sustaining life on Earth, plays a crucial role in the physical and chemical processes governing the formation of stars and planets, serving as a primary coolant in the environments surrounding emerging stars. The journey of water from the earliest stages of star and planet formation to its eventual incorporation to exoplanetary atmospheres and its potential oceans is still a matter of debate. Very recent works using ALMA and JWST data reveals that water can be found in the inner astronomical units in protoplanetary disks, in the terrestrial planet-forming zone. Detecting water molecules from ground-based telescopes is challenging due to the water vapor content within Earth’s atmosphere, severely limiting atmospheric transmissivity. Nevertheless, water is one of the few compounds capable of generating bright maser emission within star-forming regions. Their exceptional brightness, narrow spectral profiles, and their origin in highly compact regions offer a unique set of characteristics that render them invaluable tools for investigating circumstellar structure and dynamics at sub-arcsecond spatial scales. In this work we present our efforts to search and characterize water maser emission at submillimeter frequencies in a sample of young stellar objects.

Infrared observations with JWST open up a new window into the chemical composition of the gas in the inner disk (<few au) where planets are built. Results from the MIRI GTO program MINDS are presented for several disks around T Tauri and lower-mass stars. A large diversity in spectra is found. Some disks are very rich in H2O lines whereas other disks show prominent CO2. The spectra of disks around very low-mass stars (<0.3 M⊙, late-M type stars like Trappist-1) are dominated by C2H2 and other hydrocarbon features including those of benzene, suggesting volatile C/O>1. Together these data point to a rich chemistry in the inner regions that is linked to the physical structure of these disks (e.g., dust traps) and that may be affected by processes such as radial drift of icy pebbles from the outer to the inner disk.

We propose the implementation of an AstroLab project in Africa, dedicated to Astronomy and Planetary Science Education. Our goal is to contribute significantly to the development of digital education in astronomy across universities and schools on the African continent. The AstroLab project seeks to inspire and engage students from diverse cultural backgrounds by providing them with a unique opportunity to conduct astronomical research and education through remotely accessed telescopes. This initiative is particularly crucial in regions where the lack of astronomy infrastructure impedes students from hands-on experience in this field. In addition, we will implement this program in three distinct languages to ensure accessibility and inclusivity for the diverse communities of the continent.

A groundbreaking collaboration in Canada has united astrophysicists, science educators, and teachers to create Exoplanets in the Classroom – a dynamic suite of K-12 resources designed to inspire the next generation of scientists. Featuring hands-on activities, practical slide decks, engaging videos, and profiles of trailblazing Canadian astronomers, this comprehensive collection of resources is freely accessible online in both French and English. Since 2021, the Trottier Institute for Research on Exoplanets (IREx) at the Université de Montréal, in partnership with Discover the Universe and other educational innovators, has crafted these resources with input from over one hundred Canadian teachers. This rigorous, iterative process ensures seamless integration into a wide range of subjects, from science to the arts, all while meeting Canadian K-12 curriculum standards.

These innovative resources provide educators with the tools to captivate students with the wonders of exoplanet research and the stories of diverse, local scientists at the forefront of discovery. Already tested and embraced by students and teachers from diverse backgrounds, these materials are now poised to inspire a global audience, offering astrophysicists and educators a powerful way to ignite curiosity and engage learners in classrooms and beyond.

“Il cielo in salotto” (in English, “The sky in your living room”) is a format for live streaming astronomical observations created by the Italian National Institute for Astrophysics (INAF). The project started in late 2020 in the midst of the Covid-19 pandemic to engage the general public and students with astronomy and space science remotely, when observatory visits were not possible. The format later evolved, in the “new normal” scenario, as a complementary activity to in-person events, featuring astronomical phenomena - such as planet alignments, eclipses, different Moon phases, comets, sunspots, exoplanet-hosting stars - observed live by the INAF network of telescopes all around the country. These events are enriched by live interviews with INAF researchers and supported by large-scale public engagement campaigns conducted together with space enthusiasts, amateur astronomy associations and other partners. Viewers can ask questions live to the experts and also select some of the targets to observe. We present lessons learnt and best practices from three and a half years running the project, along with some of the technical and logistics, content and communication solutions adopted in the format of potential interest to colleagues organising similar events in other countries. We also discuss the results of a focus group conducted for three years in a row during the summer “SuperMoon” broadcasts, a regular programme taking advantage of the popularity of this event in the news to cover current topics in planetary science.

It was found that the cluster NGC 1977, located in the region of Orion’s Sword, in past epochs approached in space the star TOI-2796, which has a planetary system. It should be noted that in the vicinity of NGC 1977, the James Webb Space Telescope observed more than 500 free planets and free binary planets. Numerical calculations of the orbit around the Galactic Center were carried out. It is shown that these objects approached at a distance of ∼7.8 pc about ∼4.4 million years ago. This approach could have a gravitational effect on the Oort cloud analogue TOI-2796, leading to a change in the orbital elements of small bodies. It is important to note that the observed effect could be the loss of objects from the TOI-2796 planetary system into interstellar space.

The vast observational survey project aimed to search and study of variable stars in different regions of the Galaxy is presented. This project is undertaking within the frame of international research collaboration between Indian and Uzbekistan astronomers. The main targets were the open star clusters and stellar associations but we also considered a multitude of known variable stars of various types with prominent activity. The observations were carried out at Maidanak astrophysical observatory (Uzbekistan) and ARIES observatories at Devasthal and Manora Peak as well as Hanle observatory (India). The main results of the projects are presented briefly. The prospects of the project especially in a point of view to support the possible programs and projects using the James Webb Space Telescope are discussed.

This paper studies instability of the in-plane equilibrium points (EPs) which lies on the line joining the main bodies in the frame of the restricted three-body problem with Poynting-Robertson (P-R) drag force and variable masses. The dynamical structures of the primaries and their mass variation are governed by the Gylden-Mestschersky problem (GMP) and the Mestschersky combined law (MCL), respectively, under the conditions that both primaries are radiation emitters with the Doppler shift and the absorption and subsequent re-emission of the incident radiation, considered. It is seen that there can be three, four and even up to six Collinear In-plane Equilibrium Points (CIEPs). Some are independent of the P-R drag while others depend on the mass parameter and P-R drag of the primaries. The stability of the CIEPs is investigated analytically and numerically for a dust grain particle in the gravitational field of all binary systems which covers most astronomical systems, and it is seen that all the CIEPs are unstable. Additionally, it is seen that the zero velocity curves (ZVC) around the CIEP L0, for all mass parameter do not exist as the P-R drag effects are annulled in the force function. Consequently, the resulting CIEP will be located on same point as the bigger primary, which in turns means that the force function will be undefined in this case. The stability of the CIEPs of the non-autonomous system which differ from those of the autonomized system by a function of time, are unstable as they do not converge as time tends to infinity. Our problem can be applied to the description of a dust grain in the gravitational field of stellar systems with radiation force and variable masses.

Earth’s and Venus’ atmosphere mass and composition today are accumulated results of the solar hydrologic cycle over billions of years with comet collisions infusing gassy material onto the planets and solar wind blowing away the lighter gasses leaving primarily only carbon dioxide and nitrogen on both Earth and Venus. The comets entering the inner solar system have higher evaporation rate than collision probability, resulting in far less mass infusion onto inner planets than outer planets. The infused gasses onto the Earth are further processed by its chemical processes. Being too close to the Sun to have liquid water, Venus lacks chemical processes. The solar hydrologic cycle theory predicts comet mass infusion ratio between Venus and Earth to be 1:0.76. Comparing carbon dioxide and nitrogen mass in Venus atmosphere with nitrogen mass in Earth atmosphere plus carbon and nitrogen deposits in the crust, the ratio is 1:0.45-0.54.

This study presents geodynamic experiments within the outer ice shell of Ganymede to investigate the effects of partial melting into the convective layer, and trying to infer any correlation between internal processes and strain deformations in surface regions such as cryovolcanism and polar deposits. The numerical models were conducted performing a sensitive analysis of the internal dynamic for compressible fluids by varying the viscosity, ice shell thickness, pressure at the melting point of ice, and applying the Anelastic Liquid Approximation (ALA). Results show molten material under restricted geophysical parameters that could allow for emerging material from the subsurface ocean to the surface. These findings will support the objectives of the RIME instrument on board of the JUICE mission, as they point out specific conditions that may, in the future, help to have a better understanding of the internal mechanisms that transfer heat on the surface and modify the geomorphology and atmospheric processes.

FU Ori stars (FUors) are undergoing powerful luminosity outbursts of ∼100 L⊙ in magnitude and of several decades in duration. Such outbursts inevitably affect physical and chemical structure of the surrounding protoplanetary disk. Using astrochemical and radiative transfer modelling, we study the lasting impact of the outburst on disks with and without an envelope and how it changes flux in chosen molecular lines. We formulate a number of criteria indicative of a recent outburst activity based on the molecular emission, analyze the chemistry behind the flux change and apply the criteria to available observations of quiescent protoplanetary disks. The latter revealed ten objects with possible outbursts in the past and four of them satisfy multiple proposed criteria.

We explore the position and stability of the collinear Lagrangian points in the Restricted Three-Body Problem (RTBP) where one primary body is radiative and the other is oblate. We examine the influence of Poynting-Robertson drag and the position and stability of the Lagrangian points which are affected by variations in the radiation parameter and oblateness. We compare our results with ten exoplanet systems, to identify locations in these exoplanet systems where one can detect asteroids, primodial material, or seeds where planet formation can take place. Moreover, for all ten planetary systems examined in this study, the Lagrangian points are unstable and may be possible locations where minor planets, asteroids, or debris can be found. The instability of the Lagrangian points can also be a possible cause of relocation and migration of planetesimals. These could also be used as possible candidates for observations with the James Webb.