“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 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.

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.

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.

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.

Astrobiologists are moving purposefully towards the detection of extraterrestrial intelligence (ETI) through the radio and optical methods of SETI. Meanwhile, members of the public have formed their own opinions, only partially informed by science. In the United States, two thirds of all adults believe there is intelligent life beyond Earth, and a substantial minority believe we have already made contact. Opinions about the existence and nature of aliens are part of a complex landscape of beliefs that includes pseudoscience and superstition and extends to conspiracy theories. The widespread belief that unidentified flying objects (UFOs) represent visits by ETI is at the center of this landscape. Beliefs about ETI are also shaped by films, TV shows, and popular culture. This chapter summarizes what the public believes about ETI and presents possible explanations for these beliefs. Some international comparisons are presented. The author has surveyed the opinions and beliefs of tens of thousands of students on topics relating to life beyond Earth and the data gives insights into the modes of thinking of the college-age population. People are not “blank canvasses” when it comes to their beliefs and expectations about ETI, and this should be considered by the scientists who are preparing for eventual, actual contact.

On 24 May 2023, a simulated extraterrestrial message was transmitted towards Earth by the Trace Gas Orbiter, a spacecraft of the European Space Agency. The radio signal containing the message was received by several terrestrial radio antennas, as part of the interdisciplinary project “A Sign in Space”. I conceived the project in 2019, and developed it in collaboration with the SETI Institute, the Green Bank Observatory, the Italian Institute for Astrophysics and the European Space Agency. The message designed for the project required one year to be decoded by citizen scientists. The public reaction to the project provides preliminary insights into the unfolding of a concrete First-Contact scenario.

In recent years, the protection of dark and quiet skies (D&QS) has become an increasingly urgent concern, driven by the proliferation of artificial light at night (ALAN) and the deployment of mega-constellation satellites in low-earth orbit (LEO). This paper presents preliminary research findings from the IAU CPS Policy Hub National Analysis Team, focusing on the national policy and legal approaches to safeguarding D&QS for astronomical observations worldwide. It synthesises the key interim results with a primary focus on light pollution mitigation, outlining measures to combat light pollution and emerging regulatory trends. The study also identifies obstacles to mitigating light pollution and offers examples of national approaches for D&QS protection, along with future research prospects.

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.

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.

Planetary Protection is an effort to prevent inadvertent biological or organic contamination in solar system exploration. That effort cannot be perfect in actual exploration missions, but the price of not attempting it can be seen in numerous actual contamination events on Earth (e.g., kudzu and starlings in the US, Australia-released rabbits) and the more fanciful, but possibly valid, works of fiction (The War of the Worlds, The Andromeda Strain). Extraterrestrial contamination spread by Earth missions is known as forward contamination, while backward, or back contamination refers to contamination brought to Earth. Both robotic and human missions may be affected by planetary protection practices, which strive to apply the most current science to those efforts, but it is clear that those same missions may discover new information (the hope of most missions) that could argue for new and potentially altered requirements on the next mission, or on the ongoing missions themselves.

Astrobiology and SETI search for life-not-as-we-know-it (yet). Researchers aspire to an understanding not yet found. With that in mind, knowledge about three types of context can inform and improve the search. Observational context: knowing our location as humans (anthropism) can mitigate biases introduced by our desire to over-value humanity (anthropocentrism). Historical context: knowing the history of the search, not just the last 10–30 years, can clarify concepts and significance. Disciplinary context: understanding the rules by which different disciplines operate can reveal the limitations of a single perspective (astronomy, biology, ecology, sociology, law, medicine, philosophy, theology…). Astrobiology and SETI tell epic stories about the place of life in the cosmos. They locate humans morally as well as physically. We should ask why we tell them and how our context shapes the telling, because the stories shape human interactions with the world.

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.

We present perspectives from six panellists on “Life as a cosmic phenomenon facing human culture”, contrasting our experience and knowledge of life as found on Earth with the vastness of the Universe and the fact that Earth-centric and/or anthropocentric views have repeatedly proven untenable. How does an outwards view of projecting Earth-based experience into the cosmos combine with the inwards view of the potential detection of life beyond Earth telling us who we are?