We present the discovery of three sub-Neptune exoplanets orbiting M dwarf stars: TOI-2136 b (period 7.85 days, radius Rp = 2.19 ± 0.17R⊕, mass MP = 6.4 ± 2.4M⊕), TOI-2084 b (period 6.08 days, radius Rp = 2.47 ± 0.13R⊕), and TOI-4184 b (period 4.9 days, radius Rp = 2.43 ± 0.21R⊕). All discoveries utilized TESS data combined with ground-based follow-up observations for confirmation. The location of these planets near the “radius valley” suggests diverse planetary formations around low-mass stars and holds promise for future atmospheric characterization with instruments like JWST.

Our study analyzes nearby (within 33 pc) K dwarf stars to determine their stellar properties, activity levels, kinematics, and estimated ages, as part of the RKSTAR (RECONS K Star) Survey encompassing about 5000 K dwarf primaries within 50 pc. Utilizing high-resolution spectra from the CHIRON echelle spectrometer, we established a benchmark set of 35 K dwarfs aged 20 Myr to 5 Gyr, focusing on the Hα (6563 Å) and Li I (6707.9 Å) lines. We extended our analysis to 615 K dwarfs within 33 pc and found that about 8% exhibit spectroscopic features characteristic of young or active stars. As expected, Galactic UVW space motions indicate that most of the stars fall into the thin (80%) and thick (20%) disk populations, with a single outlier, HD 134439, which is a known halo star. Additionally, 4% of the stars were identified as metal-poor ([Fe/H] ≤ −0.5 dex). This work identifies 500 inactive and mature K dwarfs as prime targets for detecting terrestrial planets and serves as a vital resource for assessing host star suitability for exoplanet habitability.

The contention of this paper is that alien visitation claims are a societal problem when they (a) move into the mainstream of discourse to the extent that government policy has to respond to them; (b) when they generate background noise which impedes science communication; and (c) when they become entangled with indigenous origin narratives, making it hard to recover the latter. Where this is the case, periodic debunking looks like a failed paradigm. Something closer to a scientific research program (SRP) might be called for, at some point. This is an idea which has already been advanced by Avi Loeb and Martin Elvis (albeit in significantly different ways and for different reasons). It is not clear that we are already at the stage where an SRP is required, but such a requirement does seem to be on the near horizon.) The paper concludes by setting out a number of framing requirements for any such SRP.

We present a solution of a devil’s advocate to put telescopes in space, as one possible way to mitigate the impact on astronomy and on the night sky of recent large satellite constellations. The limitations of telescopes in space versus on Earth are noted. However, the solution draws from the history of telescopes that had to be moved from major human settlements to rural areas in the past; and it poses que question if it is possible that the future may lead to similar moves of putting telescopes in space, as satellites become a major human development similar to human development of cities that pushed telescopes out of cities to rural areas in the past.

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.

Context. Modern polarimeters enable precise measurements of exoplanetary systems, providing valuable constraints on orbital geometry and atmospheric scattering properties.

Aims. We aim to investigate the orbital parameters of the non-transiting Jupiter-like exoplanet ʋ And b, which orbits close to its host star, using polarized scattered light observed with the DiPol-2 polarimeter on a 60 cm telescope.

Methods. Over nearly three years, we collected high-precision polarimetric data of the ʋ And system. Using Lomb-Scargle periodograms, we identified variability close to the planetary orbital phase and modeled the signal with the Rayleigh-Lambert approximation.

Results. A weak polarimetric signal at half the orbital period of ʋ And b was detected. The V-band MCMC fits yielded an orbital inclination of , an argument of periastron , a longitude of ascending node , and a geometric albedo of . Although uncertainties remain large, the inclination result agrees with earlier estimates, supporting a low-inclination, non-transiting geometry.

Conclusions. While the detection is not definitive, these results demonstrate the capability of high-precision polarimetry to probe the orbital parameters of non-transiting exoplanets. Further observations with larger telescopes and improved sensitivity will be required to refine the constraints on the orbital parameters.

Orbital anomalies, such as unexpected changes in a satellite’s orbit, can significantly impact satellite operations and threaten human and financial resources. Detecting these anomalies is a crucial challenge in data analysis within the spatial domain. During satellite operations, a large amount of data is generated, These data allow us to assess the satellite’s state at a specific moment. This paper introduces a study aimed at developing a diagnostic algorithm using machine learning techniques to classify orbital anomalies. The proposed algorithm will be able to classify these anomalies based on their origins using various supervised learning models. The performance of the algorithms used was measured by comparing their accuracy and using the confusion matrix over five distinct classes of orbital anomalies.

Historically, information about radio astronomy observatories to be used in sharing and compatibility studies was provided by the relevant national administrations responsible for their radio astronomy observatories. The IAU CPS provides a streamlined platform for radio astronomy observatories and satellite operators to collaborate on sharing and compatibility studies prior to enrolling on the national or international regulatory framework, reducing the burden on national administrations. This leads to the requirement to have an alternative solution to have information about radio astronomy observatories. We discussed currently used alternative data collection as well as shared the information on the creation of a CPS-based database to serve as a source of radio astronomy observatories characteristics for sharing and compatibility studies to be carried out within IAU CPS.

The Astronomy Center (CITEVA) of the Universidad de Antofagasta manages the Ckoirama Observatory and the Astroengineering Laboratory of the Atacama Desert. The former is undergoing an expansion thanks to funding approved by the Chilean Science Agency (ANID) in 2022, with support from other Chilean universities, the Chilean Air Force, and the IAU CPS, so that a new satellite tracking station will begin operations in 2024, specifically designed to collect reflected sunlight from satellites. The latter, on the other hand, is developing an experimental setup designed to test space-grade materials in order to contribute data to produce bidirectional reflectance distribution function models of satellites.

We present the progress of work to streamline and simplify the process of exoplanet observation by citizen scientists. International collaborations such as ExoClock and Exoplanet Watch enable citizen scientists to use small telescopes to carry out transit observations. These studies provide essential supports for space missions Such as JWST and ARIEL. Contributions include maintenance or recovery of ephemerides, follow up confirmation and transit time variations. Ongoing observation programs benefit from a large pool of observers, with a wide variety of experience levels. Our projects work closely with these communities to streamline their observation pipelines and enable wider participation. Two complementary approaches are taken: Star Guide applies human-centric design and community consultation to identify points of friction within existing systems and provide complementary online tools and resources to reduce barriers to entry to the observing community. Machine Learning is used to accelerate data processing and automate steps which are currently manual, providing a streamlined tool for citizen science and a scalable solution for large-scale archival research.

To capture images of Earth-like planets orbiting distant stars, advanced instruments with exceptional contrast ratios are imperative. While coronagraphs play a crucial role, they often lack the capability to achieve the requisite contrast levels independently. Hence, supplementary apodization techniques are indispensable for augmenting their rejection capabilities. In this context, we introduce an innovative apodization method that harnesses interferometry, seamlessly integrating a deformable mirror into the Michelson interferometer setup. This sophisticated approach entails splitting the incident Point Spread Function (PSF) into two components, introducing an additional inhomgenious phase φ(x, y) to one of them via a deformable mirror, and subsequently recombining them to yield an apodized PSF. We illustrate, in particular, the influence of several parameters of the deformable mirror on the optimization of the additional phase profile.

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.

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.

Until now, there has been no evidence of the existence of life forms other than on Earth. The philosophical, ethical and theological corpus that has been built up on this subject over several millennia is therefore based on a thought experiment or a posture of belief. Between dealing with a heresy and applying the precautionary principle, extraterrestrials represent a special opportunity to question the boundaries of our systems of thought, and sometimes to shake up dogmatism.

We consider the dynamic evolution of the compact four-planetary system K2-72. We considered a few scenarios for the evolution of the K2-72 system over 100 Myr using the Posidonius software, which considers tidal interactions. We showed that the compact planetary system K2-72 likely evolves beyond low-order resonances. A significant change in the large semi-major axes of the orbits of the K2-72 b and K2-72 d planets leads to the moving of the adjacent planets b-d and d-c out of the 7/5 and 8/5 resonance regions, respectively. The adjacent planets K2-72 d and K2-72 c are located far from the 2/1 resonance, which excludes the possibility of forming chains of mean motion resonances and, hence, 3-planet mean motion resonances. If the orbital eccentricities do not exceed 0.03, the evolution of the compact planetary system K2-72 over 100 Myr remains stable even in the presence of tidal perturbations.

Telkom-1 is a geosynchronous communications satellite owned by telecommunications company, PT Telkom Indonesia. This paper will discuss solar radiation pressure as one of the most significant perturbations in geostationary orbits. Solar radiation pressure models come in various types, each differing in complexity and accuracy. The simplest solar radiation pressure model is a spherical model, often used for educational or preliminary calculations. Based on our modelling, the results indicate that the semimajor axis values from the spherical model closely approximate the actual data. However, the eccentricity calculated from the spherical model is nearly ten times larger than that derived from the actual data. Additionally, the amplitude of the mean anomaly from the spherical model increases over time, and the spherical model of inclination also demonstrates an increasing trend with time.

The growing international public attention to astrobiology and SETI, combined with the immense costs of space exploration and the potential outcome, the discovery of extraterrestrial life, will likely increase the pressure for public justification and the need to address societal concerns about the risks of searching for, finding, or being found by extraterrestrial life. Understanding these perceptions and concerns warrants a more systematic inclusion of risk communication research in studying pre- and post-detection scenarios. In this chapter, we review the state of the art in risk perception/communication research related to astrobiology and detection. Based on three major challenges (social risk amplification/attenuation, misguided risk information seeking, ineffective risk message design), we explore the contribution of risk communication theory (SARF, RISP, EPPM, IDEA) to future research and institutional preparedness for potential detections of extraterrestrial life.