Acidithiobacillus ferrooxidans is a Gram-negative bacterium that thrives in extreme acidic conditions. It has emerged as a key player in biomining and bioleaching technologies thanks to its unique ability to mobilize a wide spectrum of elements, such as Li, P, V, Cr, Fe, Ni, Cu, Zn, Ga, As, Mo, W, Pb, U, and its role in ferrous iron oxidation and reduction. A. ferrooxidans catalyzes the extraction of elements by generating iron (III) ions in oxic conditions, which are able to react with metal sulfides. This review explores the bacterium’s versatility in metal and elemental mobilization, with a focus on the mechanisms involved, encompassing its role in the recovery of industrially relevant elements from ores. The application of biomining technologies leveraging the bacterium’s natural capabilities not only enhances element recovery efficiency, but also reduces reliance on conventional energy-intensive methods, aligning with the global trend towards more sustainable mining practices. However, its use in biometallurgical applications poses environmental issues through its effect on the pH levels in bioleaching systems, which produce acid mine drainage in rivers and lakes adjacent to mines. This dual effect underscores its potential to shape the future of responsible mining practices, including potentially in space, and highlights the importance of monitoring acidic releases in the environment.

With the increasing number of planets discovered by the Transit Exoplanet Survey Satellite, the atmospheric characterization of small exoplanets is accelerating. L98-59 is an M-dwarf hosting a multiplanet system, and so far, four small planets have been confirmed. The innermost planet b is ∼15% smaller and ∼60% lighter than Earth, and should thus have a predominantly rocky composition. The Hubble Space Telescope observed five primary transits of L98-59 b in 1.1–1.7 μm, and here we report the data analysis and the resulting transmission spectrum of the planet. We measure the transit depths for each of the five transits and, by combination, we obtain a transmission spectrum with an overall precision of ∼20 ppm in for each of the 18 spectrophotometric channels. With this level of precision, the transmission spectrum does not show significant modulation, and is thus consistent with a planet without any atmosphere or a planet having an atmosphere and high-altitude clouds or haze. The scenarios involving an aerosol-free, H₂-dominated atmosphere with H₂O or CH₄ are inconsistent with the data. The transmission spectrum also disfavors, but does not rule out, an H₂O-dominated atmosphere without clouds. A spectral retrieval process suggests that an H₂-dominated atmosphere with HCN and clouds or haze may be the preferred solution, but this indication is nonconclusive. Future James Webb Space Telescope observations may find out the nature of the planet among the remaining viable scenarios.

We statistically validated a sample of hot Neptune candidates applying a two-step vetting technique using DAVE and TRICERATOPS. We performed a systematic validation of 250 transit-like events in the Transiting Exoplanet Survey Satellite (TESS) archive in the parameter region defined by P ≤ 4 d and 3 R_⊕ ≤ R ≤ 5 R_⊕. Through our analysis, we identified 18 hot Neptune-sized candidates, with a false positive probability |$< 50\%$|⁠. Nine of these planet candidates still need to be confirmed. For each of the nine targets we retrieved the stellar parameters using ARIADNE and derived constraints on the planetary parameters by fitting the lightcurves with the juliet package. Within this sample of nine candidates, we statistically validated (i.e, with false positive probability |$< 0.3\%$|⁠) two systems (TOI-277 b and TOI-1288 b) by re-processing the candidates with TRICERATOPS along with follow-up observations. These new validated exoplanets expand the known hot Neptunes population and are high-priority targets for future radial velocities follow-up.

Our understanding of the diversity of life on our planet and the possibility of finding or sustaining life elsewhere in the universe plays a central role in supporting human space settlement and exploration. Astrobiology and its outcomes require a multidisciplinary and comprehensive approach, in which the microbial, geological, chemical, astronomical, and physical domains of research are interlinked. An example of the applications of astrobiology and space microbiology is the use of extremophiles for in situ resource utilization through biomining and bioleaching. To better understand the multidisciplinary research landscape in this area, we quantitatively reviewed the global scientific literature on astrobiology, with a focus on biomining and bioleaching through bibliometric network analysis, investigating patterns and trends in its development over time. The network analysis of keyword co-occurrence highlights different connecting and overlapping clusters, illustrating the multidisciplinary character of astrobiology. Temporal analyses show a recent focus on topics related to microbiology and geomicrobiology, emphasizing the role that these fields will play in future astrobiology research. In conclusion, astrobiology, biomining, and bioleaching research are currently addressing the recognition of these techniques as valuable tools for biotechnological applications, expected to play a crucial role in long-term human space exploration.

The Transiting Exoplanet Survey Satellite (TESS) mission is providing the scientific community with millions of light curves of stars spread across the whole sky. Since 2018, the telescope has detected thousands of planet candidates that need to be meticulously scrutinized before being considered amenable targets for follow-up programs. We present the second catalog of the Planet Patrol citizen science project containing 999 uniformly vetted exoplanet candidates within the TESS ExoFOP archive. The catalog was produced by fully exploiting the power of the Citizen Science Planet Patrol project. We vetted TESS Objects of Interest (TOIs) based on the results of Discovery And Vetting of Exoplanets (dave) pipeline. We also implemented the automatic disposition generator, a custom procedure aimed at generating the final classification for each TOI that was vetted by at least three vetters. The majority of the candidates in our catalog, 752 TOIs, passed the vetting process and were labelled as planet candidates. We ruled out 142 candidates as false positives and flagged 105 as potential false positives. Our final dispositions and comments for all the planet candidates are provided as a publicly available supplementary table.

We present observations of the 1.35 ± 0.07 Earth radius planet L 98-59 c, collected using Wide Field Camera 3 on the Hubble Space Telescope (HST). L 98-59 is a nearby (10.6 pc), bright (H = 7.4 mag) M3V star that harbors three small, transiting planets. As one of the closest known transiting multi-planet systems, L 98-59 offers one of the best opportunities to probe and compare the atmospheres of rocky planets that formed in the same stellar environment. We measured the transmission spectrum of L 98-59 c, and the extracted spectrum showed marginal evidence (2.1σ) for wavelength-dependent transit depth variations that could indicate the presence of an atmosphere. We forward-modeled possible atmospheric compositions of the planet based on the transmission spectrum. Although L 98-59 was previously thought to be a fairly quiet star, we have seen evidence for stellar activity, and therefore we assessed a scenario where the source of the signal originates with inhomogeneities on the stellar surface. We also see a correlation between transits of L 98-59 c and L 98-59 b collected 12.5 hr apart, which is suggestive (but at <2σ confidence) of a contaminating component from the star impacting the exoplanet spectrum. While intriguing, our results are inconclusive and additional data are needed to verify any atmospheric signal. Fortunately, additional data have been collected from both the HST and James Webb Space Telescope. Should this result be confirmed with additional data, L 98-59 c would be the first planet smaller than 2 Earth radii with a detected atmosphere.