As the number of large Earth-orbiting satellite networks (i.e., mega-constellations or mega-sats) increases, so does the threat posed to astronomical research. Bright satellite trails in exposures of the night sky can affect the quality of observations and hinder science objectives. Using the MASCARA station to detect satellites from the SpaceX Starlink network as a representative case, this study quantifies the present and future impact of mega-sats on ground-based optical astronomy. We find that further design revisions are required to mitigate the brightness concern of pre-Gen2 Starlinks and that hundreds of satellites could be visible in all-sky observations at peak observing times if additional measures are not taken.

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.

“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.

The study of strong solar energetic particles (SEPs) allows one to understand their acceleration and propagation in interplanetary space and gives the necessary basis to quantify the related cosmic-ray-induced terrestrial and space weather effects. During solar eruptive processes, such as solar flares and/or coronal mass ejections solar ions are accelerated to a high energy range. In most cases, the energy of the accelerated solar ions reaches several tens of MeV/nucleon, yet occasionally it exceeds 100 MeV/n or even reaches the GeV/n range. In the latter case, the energy of SEPs is enough, so that they induce a complicated particle shower in the earth’s atmosphere, whose secondary particles reach the ground, eventually registered by ground-based detectors, such as neutron monitors (NMs). This particular class of events is known as ground-level enhancements (GLEs). Here we present a method for the analysis of GLEs, using neutron monitor data. Verification of the method with direct space-borne measurements is performed and good agreement is achieved. The derived SEP spectra give the necessary basis to model and quantify cosmic-ray-induced terrestrial and space weather effects following major solar eruptions. We present an example study, that is a full chain analysis of notable GLEs, namely their SEP energy/rigidity spectra derived using records from the global NM network and a model for computation of the induced space weather effects i.e. effective doses during those events.

Strong solar flares and coronal mass ejections (CMEs) are prone to originate within and near active regions (ARs) with a high magnetic complexity. Therefore, to better understand the generation mechanism of flares and the resultant CME eruption and to gain insight into their stellar counterparts, it is crucial to reveal how solar flare-productive ARs are generated and developed. In this review, first, we summarize some general aspects of solar flares and key observational characteristics of such ARs. Then, we discuss a series of flux emergence simulations that were performed to elucidate the subsurface origins of their complexity and introduce state-of-the-art models that consider the effect of turbulent thermal convection. Future flare observations using SOLAR-C, a next-generation high-throughput extreme ultraviolet spectroscopy mission, are also discussed.

Large-scale solar eruptions often include ejection of a filament, a solar flare, and expulsion of a coronal mass ejection (CME). Unravelling the magnetic processes that build up the free energy for these eruptions and trigger that energy’s release in the eruption is a continuing challenge in solar physics. Such large-scale eruptions are comparatively infrequent, with the moderate level ones (say, GOES M-class events) occurring perhaps once every few days on average during active-activity times, and much less frequently during quieter times. In contrast, solar coronal jets, which are long (: 50,000 km), narrow (less than about 10,000 km), transient (: 10—20 min) plasma spires with bright bases and that are seen in soft X-rays and EUV, occur much more frequently, likely several hundred times per day independent of large-scale solar activity level. Recent studies indicate that coronal jets are small-scale versions of large-scale eruptions, often produced by eruption of a small-scale “miniflament,” that results in a “miniflare” analogous to a larger typical solar flare, and that sometimes produces a CME analogue (a “narrow CME” or “white-light jet”). Under the assumption that jets are small-scale eruptions, their higher occurrence frequency and faster build-up evolution reveals perhaps fundamental aspects of all eruptions that are not as easy to discern in the more-complex magnetic environment and the slower build up to the larger eruptions. Therefore, the study of coronal jets can provide insights into the onset mechanism of CME-producing large-scale eruptions.

We carried out spectroscopic observations of an active K-dwarf LQ Hya using the 3.8-m Seimei telescope and 1.88-m telescope at Okayama Observatory simultaneously with the photometric observation by the Transiting Exoplanet Survey Satellite (TESS). During our observing run, we successfully detected a superflare with the bolometric energy of 1035 erg. The Hα line width significantly increased from ∼ 3 Å to ∼ 18 Å during the rising phase of the superflare and peaked at almost the same time as the flare peak time of optical continuum flux. In addition, the Hα line profile showed no line asymmetry during the flare. The absence of the line asymmetries in the Hα line suggests that the mass of the erupted plasma is smaller than 1017–1018 g if we assume that the observed superflare was accompanied by the solar-like filament/prominence eruption with the velocity of ∼500 km s−1.

The study of cosmic rays (CRs) and their interactions with exoplanetary atmospheres and stellar environments can provide essential insights into the habitability and atmospheric chemistry of these distant worlds. For instance, on Earth, radiation from cosmic rays constitutes only about 10 percent of the total radiation exposure at ground level, but this percentage can be significantly higher for planets orbiting stars close to cosmic ray sources. Furthermore, the modulation of cosmic rays varies considerably among different stars. This research focuses on modelling the modulation of CRs by various stellar types, particularly F, G, K, and M stars, to understand the impact on exoplanets in their habitable zones. Employing an analytical one-dimensional model of the Cosmic Ray Transport Equation, which allows us to study a wide range of parameters, we analyse how different stellar parameters, such as wind speed and magnetic field strength, influence the cosmic ray environment. The developed model simulates the cosmic ray spectra and mean free path, considering factors like the star’s relative motion through the interstellar medium. This work aims to contribute to the understanding of radiation conditions on exoplanets, which is crucial for assessing their potential to support life. It offers a preliminary but meaningful exploration into the complex interactions between cosmic rays and exoplanetary environments, shedding light on factors that might influence the habitability of these alien worlds.

Exoplanet follow-up with JWST requires precise masses and radii. HARPS-N is a high-resolution spectrograph on the Telescopio Nazionale Galileo (TNG), predominantly used to detect and characterize exoplanets using the radial velocity (RV) method. The HARPS-N Collaboration has been characterising exoplanets with HARPS-N for over a decade. In this short paper we highlight the contributions that the HARPS-N Collaboration has made to the characterisation of small exoplanets.

The rising number of exoplanet discoveries and advances in machine learning (ML) techniques present new possibilities for exploring and understanding the characteristics of worlds beyond our solar system. This research examines the exoplanet dataset by applying ML techniques to categorize these systems, uncover relationships among their physical features, and predict the exoplanet radius. We group the data into two primary categories: ‘small’ and ‘giant’ planets, with thresholds at Rp = 8.13R⊕ and Mp = 52.48M⊕. Our study indicates that the planetary mass, orbital period, and stellar mass play critical roles in predicting the exoplanet radius. A notable finding of our research is that small planets exhibit a positive linear mass-radius relationship, consistent with other studies. Conversely, for giant planets, we observe a strong correlation between planetary radius and the mass of their host stars, potentially providing significant insights into the relationship between giant planet formation and stellar properties.

The search for habitable planets and signatures of extraterrestrial life is one of the most ambitious and consequential projects of our civilization. Observations taken with Kepler, Transiting Exoplanet Survey Satellite (TESS) and the Hubble Space Telescope have detected over 5600 exoplanets suggesting that majority of young rocky exoplanets in the habitable zones around magnetically active cool stars are exposed to extreme stellar coronal X-ray, Extreme UV (EUV) and particle fluxes. They have also revealed frequent (super) flares on young solar-like planet hosting stars, providing a mechanism by which host stars may have profound effects on the physical and chemical evolution of exoplanetary atmospheres. Recent data including our observational campaigns of EK Dra suggest that superflares from young solar analogs are accompanied by fast and energetic coronal mass ejections (CMEs). As CMEs propagate out from the stellar corona into interplanetary space at a few thousand km/s, they drive strong and extended shocks. Shocks are the sites of efficient acceleration of stellar energetic particles (StEPs) to tens of GeVs via diffusive shock acceleration. While CMEs interact with magnetospheres of rocky planets by disturbing them, StEPs can penetrate (exo)planetary atmospheres via open magnetic field and cause significant changes in atmospheric chemistry. Here, I will describe our recent results of observational data-constrained 3D MHD models of initiation and propagation of CMEs in coronae of young solar-like stars and acceleration of shock driven stellar energetic particles (StEP) to 40 GeV. I will then review our recent models of CME interaction with magnetospheres of rocky exoplanets that provide an efficient way for precipitation of StEPs into planetary lower atmospheres. I will also discuss how the flare/StEP modified chemistry may affect climates of rocky exoplanets, the critical factor of habitability. This model was recently validated with our laboratory experiments of proton irradiation of gas mixtures representative of a weakly reducing volcanicaly driven secondary atmospheres of young rocky exoplanets. I will discuss the implications of our recent theoretical simulations and laboratory experiments for the conditions required to find a prebiotic exoplanet around a solar-like stars and its pre-biosignatures.

We discuss that, when considering discovery or searching for life on other planets, we have to take note that such life could be in any comparative time snapshot. Furthermore, the evolutionary scenario might work out differently, depending on the initial conditions.

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.

This article examines four different points where an astrological or astrobiological discovery might propose a challenge for Christian religion. These points of contact are the size of the cosmos, human uniqueness, Christological considerations and the ultimate fate of the cosmos. I argue that the most popular interpretations of these challenges are not very serious, while there are certain issues that may genuinely push Christian religion and theology to reconsider some topics in their belief system.

We present the observations of a quiescent filament eruption and its deflection from the radial direction. The event occurred in the southern solar hemisphere on 2021 May 9 and was observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO), by the STEREO -A Observatory and GONG. Part of the filament erupted in the west direction, while major part of the filament deviated towards east direction. LASCO observed a very weak CME towards the west direction where it faded quickly. Moreover, the eruption was associated with CME observed by STEREO A COR1 and COR2. Our observations provide the evidence that the filament eruption was highly non-radial in nature.

The CHaracterising ExOPlanet Satellite (CHEOPS) is a partnership between the European Space Agency and Switzerland with important contributions by 10 additional ESA member States. It is the first S-class mission in the ESA Science Programme. CHEOPS has been flying on a Sun-synchronous low Earth orbit since December 2019, collecting millions of short-exposure images in the visible domain to study exoplanet properties.

A small yet increasing fraction of CHEOPS images show linear trails caused by resident space objects crossing the instrument field of view. CHEOPS’ orbit is indeed particularly favourable to serendipitously detect objects in its vicinity as the spacecraft rarely enters the Earth’s shadow, sits at an altitude of 700 km, and observes with moderate phase angles relative to the Sun. This observing configuration is quite powerful, and it is complementary to optical observations from the ground.

To characterize the population of satellites and orbital debris observed by CHEOPS, all and every science images acquired over the past 3 years have been scanned with a Hough transform algorithm to identify the characteristic linear features that these objects cause on the images. Thousands of trails have been detected. This statistically significant sample shows interesting trends and features such as an increased occurrence rate over the past years as well as the fingerprint of the Starlink constellation. The cross-matching of individual trails with catalogued objects is underway as we aim to measure their distance at the time of observation and deduce the apparent magnitude of the detected objects.

As space agencies and private companies are developing new space-based surveillance and tracking activities to catalogue and characterize the distribution of small debris, the CHEOPS experience is timely and relevant. With the first CHEOPS mission extension currently running until the end of 2026, and a possible second extension until the end of 2029, the longer time coverage will make our dataset even more valuable to the community, especially for characterizing objects with recurrent crossings.

The KAVLI-IAU Symposium (IAUS 387), held on April 15-19, 2024 at University of Durham, UK, brought together specialists from a range of complementary fields to discuss the probability of extraterrestrial life, methods of detection and the ramifications of its detection for humanity, The Symposium underscored the need for strong cooperation between scientists, ethicists, theologians, and journalists. Critical outcomes included the exploration of detection protocols to elevate the credibility of the Search for Extraterrestrial Intelligence (SETI), and the need to increase outreach activities on the possibility of life detection (or non-detection). The Symposium’s Discussion panels focussed on the importance of defining life, extending the concept of habitability, and exploring the Great Filter. The Symposium concluded with a strong advocacy for integrating these perspectives into global sustainability policies, highlighting the benefits of astrobiology for understanding both the cosmos and Earth.

Type II radio bursts, characterized by their slow frequency drift, are associated with accelerated electron beams at coronal mass ejection (CME)-driven shock fronts. These bursts serve as crucial indicators of shock propagation and space weather phenomena. Recently, Krupar et al. (2024) introduced a wavevector correction technique, initially applied to type III bursts, to account for the scattering effects in the solar wind, thereby enhancing triangulation accuracy. In this study, we investigate the application of this correction to type II bursts, aiming to improve localization and understand their relation to CME dynamics. We compare the corrected type II source locations with white-light observations of CMEs and in situ measurements of interplanetary shocks. Our findings indicate a significant improvement in the correlation between radio triangulation results and both white-light and in situ data, underscoring the potential of this correction method to refine our understanding of CME propagation and its impact on space weather forecasting.

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.

The Search for Extraterrestrial Intelligence (SETI) is, at its core, a grand endeavour in communication. While we hope to detect signals from intelligent civilisations beyond our solar system, searching for cosmic company has profound implications for our species’ curiosity, technological capabilities, and innate need to connect socially. It gives pause for thought that while we focus the search and post-detection, we undervalue what evolutionary psychologists assert, neuroscientists have demonstrated, science communicators know works in connecting science with society, and journalists employ: We are hardwired for storytelling by evolution, remaining our most effective form of communication. What if the most important message is not from the stars but what the search tells about wanting to know what is in the last chapter of one of the most profound stories ever told? Should the experiment succeed, the stories of survival of intelligence from a distant civilisation may be of most interest.