Frontiers in Astronomy and Space Sciences最新文献

{"title":"A hidden pattern? Common polyextremophilic microbial adaptations in Icy Moon analog environments.","authors":"Sandra Gusi-Martínez, Alberto G Fairén, Miguel Ángel Fernández-Martínez","doi":"10.3389/fspas.2026.1786844","DOIUrl":"10.3389/fspas.2026.1786844","url":null,"abstract":"<p><p>The search for life signatures beyond Earth is one of the main objectives of space exploration. Studies of analogous terrestrial ecosystems have shed light on the limits of life and on the adaptations of microbial communities to thrive in these extreme environments resembling Icy Moons. However, their findings tend to be compartmentalized, which hinders the drawing of broad conclusions about the drivers and challenges for life. This study aims to identify general characteristics of microbial communities inhabiting terrestrial analogs of Icy Moons, applying a novel meta-analysis on publicly available <i>16S rRNA</i> amplicon sequencing data. We also seek to apply our findings to a new fundamental approach in the search for life in Europa and Enceladus, locations where life may exist. Our results suggest that depth, pH and hypersalinity are the key environmental drivers for microbial taxa distribution and molecular adaptations, with halophilic archaea showing ubiquitous presence. Integrating diverse datasets into a single meta-analysis allowed us to infer statistically significant microbial patterns related to adaptation to the Icy Moons' analog conditions, notably that osmolytes and modified lipids emerged as a shared adaptive strategy, regardless of depth. Our findings are aimed to helping guide future life detection efforts in these extraterrestrial environments.</p>","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"13 ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7619085/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147965225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative stratigraphic volume of Martian lowlands using Noachian crater statistics: new bounds on volcanic effusion and flooding epochs.","authors":"Francesco Salese, Eric Hiatt, Monica Pondrelli, Marc A Hesse, Matilda Soldano, Alberto G Fairén","doi":"10.3389/fspas.2025.1675588","DOIUrl":"10.3389/fspas.2025.1675588","url":null,"abstract":"<p><p>The thickness and volume of the stratigraphic sequence in Mars' northern lowlands remain poorly constrained, despite their key role in recording the planet's geological and paleoclimatic evolution. Reliable thickness estimates are essential because they directly control calculations of volcanic effusion, surface flooding, and associated climate forcing. Here we present a revised volumetric assessment of the lowland stratigraphy - dominated by volcanic infill - based on integrated geological mapping and crater-statistical modeling. Our approach combines crater size-frequency distributions with volumetric reconstructions of buried craters and intercrater plains across both lowland and Noachian highland reference terrains. The results indicate that the minimum cumulative stratigraphic volume is at least three times greater than previous estimates, implying a proportional increase in volcanic outgassing of CO₂, H₂O, and SO₂. These new quantitative conservative bounds provide improved constraints on early Martian volatile budgets and on mid- to late-Noachian atmospheric evolution, with implications for transient climate warming and late-stage lowland flooding.</p>","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"12 ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7619066/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147869956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Super bolide explosion in the upper atmosphere and possible implications for very low earth orbit satellites: a case study on May 25, 2023","authors":"A. A. Pimenta, Oluwasegun M. Adebayo, C. M. Wrasse, R. de Jesus, A. M. Santos, P. P. Batista, V. F. Andrioli, P. R. Fagundes, E. A. Kherani, Siomel Savio, O. F. Olajide","doi":"10.3389/fspas.2025.1689801","DOIUrl":"https://doi.org/10.3389/fspas.2025.1689801","url":null,"abstract":"This event is the first documented study in the Brazilian sector regarding a super bolide whose explosion was equivalent to 21 kilotons of TNT (∼8.83 × 10 13 J). The energy released by this event in the altitude range from 96 to 99 km in the upper atmosphere was equivalent to the atomic bomb detonated at an altitude of approximately 550 m over the Nagasaki city, Japan, during World War II. This observation was detected by all-sky images system with a filter in near infrared (NIR) band from 715 to 930 nm, operating at Cachoeira Paulista (22.7°S, 45°W) and lidar observations of the mesospheric sodium and potassium layers, operating at São José dos Campos (23.1°S, 45.9°W), both observatories in Brazil. The all-sky images system showed strong explosion in the mesosphere and a subsequent long-lived meteor train with more than 14 min through the NIR band. On the other hand, the lidar showed that the meteor explosion occurred in an altitude range from 96 to 99 km with the consequent sodium and potassium atoms enhancement on the background layers. Shortly after the fireball explosion, a digisonde operating at Cachoeira Paulista detected a sudden appearance of a sporadic-E layer. Using GNSS data, an analysis of the generation of infrasonic pressure waves excited during meteor explosion is presented. In addition, thermospheric neutral density values obtained with Swarm Satellite B prior to, during, and after 25 May 2023, showed a neutral density peak on 25 May 2023, at ∼ 12 UT, after the super bolide explosion (∼4.5 h later), and reached approximately 0.574 × 10 −12 kg/m 3 , 15% above the average neutral density value prior to event. In this work we present and discuss several features related to this super bolide explosion in the upper atmosphere/ionosphere.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://public-pages-files-2025.frontiersin.org/journals/astronomy-and-space-sciences/articles/10.3389/fspas.2025.1689801/pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147906227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Space weather effects over SAMA during the extreme geomagnetic storm on May 10-11, 2024: disturbances of the neutral and ionized atmosphere","authors":"L. A. Da Silva, Jiankui Shi, L. R. Alves, L. C. A. Resende, L. E. A. Vieira, J. E. R. Costa, J. P. Marchezi, O. V. Agapitov, D. G. Sibeck, A. M. Santos, V. F. Andrioli, P. R. Jauer, Vinicius Deggeroni, C. S. Carmo, Prosper K. Nyassor, Sony Su Chen, Toyese Tunde Ayorinde, Karen Júlia Coldebella Ferreira, Juliano Moro, Chi Wang, Hui Li, Z. Liu","doi":"10.3389/fspas.2025.1550635","DOIUrl":"https://doi.org/10.3389/fspas.2025.1550635","url":null,"abstract":"A complex active region in the Sun’s photosphere from 8 May 2024, produced seven halo-type Coronal Mass Ejections (CMEs) following extreme solar flares. These events generated Solar Energetic Particles (SEPs) that propagated toward Earth, culminating in an extreme geomagnetic storm (SYM-H = −497 nT) from May 10 to 13 May 2024. This study analyzes the Sun’s photosphere, interplanetary medium, inner radiation belt, and the space weather impacts on the neutral atmosphere and E and F ionospheric layers over the South Atlantic Magnetic Anomaly (SAMA) during the storm’s main phase. The first and second Interplanetary CMEs (ICMEs) reached Earth’s bow shock at 15:00 UT and 17:00 UT on May 10, respectively. The second ICME, associated with a shock, caused a significant displacement of the dayside magnetopause (∼6 Earth radii, RE) and the first solar wind Poynting flux transfer into the magnetosphere (Akasofu parameter, Epsilon ∼ 1 × 10 13 W). At 18:00 UT, the third ICME and its associated shock pushed the magnetopause further to ∼5 RE and added energy to the magnetospheric budget (Epsilon ∼2.5 × 10 13 W). Between 19:00 and 21:00 UT, the solar wind proton density (&amp;gt;40 cm -3 ) peaked at Earth’s bow shock, but no energy input to the magnetosphere occurred (Epsilon ∼0 W). Low-energy electron/ion fluxes vanished in the inner radiation belt. Epsilon gradually increased between 21:00 and 22:30 UT, coinciding with the onset of low-energy electron/ion injections into the inner radiation belt and substorm activity. These injections persisted after 22:30 UT, albeit limited to specific energy levels. Enhanced energetic particle precipitation (EPP) and local particle acceleration caused significant variability in electron/ion fluxes in the inner radiation belt. Increased scattering by plasma waves precipitated particles into the SAMA atmosphere, raising ionization rates and depleting ozone in the mesosphere and stratosphere. Extra ionization in the E ionospheric region further indicated auroral-like effects in this low-latitude region during the storm’s main phase.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.frontiersin.org/journals/astronomy-and-space-sciences/articles/10.3389/fspas.2025.1550635/pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147916398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-messenger emission characteristics of blazars","authors":"Ronald Gamble, Jordan Forman, A.J. Barnes, Gokul P. Srinivasaragavan, Isiah Holt, Marvin Jones","doi":"10.3389/fspas.2024.1401891","DOIUrl":"https://doi.org/10.3389/fspas.2024.1401891","url":null,"abstract":"Multi-messenger observations and theories of astrophysical objects are rapidly becoming a critical research area in the astrophysics scientific community. In particular, point-like objects such as BL Lacertae (BL Lac) objects, flat-spectrum radio quasars (FSRQs), and blazar candidates of uncertain type (BCUs) are of distinct interest to researchers studying the synchrotron, Compton, neutrino, and cosmic ray emissions sourced from compact objects. Notably, there is also much interest in the correlation between multi-frequency observations of blazars and neutrino surveys on source demographics. In this review, we look at such multi-frequency and multi-physics correlations of the radio, X-ray, and <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" id=\"m1\"><mml:mi>γ</mml:mi></mml:math> -ray fluxes of different classes of blazars from a collection of survey catalogs. This multi-physics survey of blazars shows that there are characteristic cross-correlations in the spectra of blazars when considering their multi-frequency and multi-messenger emission. In addition, a review of cosmic ray and neutrino emissions from blazars and their characteristics is presented.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147922053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of collisional analysis to the differential velocity of solar wind ions","authors":"E. Johnson, B. A. Maruca, M. McManus, M. Stevens, K. G. Klein, P. Mostafavi","doi":"10.3389/fspas.2023.1284913","DOIUrl":"https://doi.org/10.3389/fspas.2023.1284913","url":null,"abstract":"Collisional analysis combines the effects of collisional relaxation and large-scale expansion to quantify how solar wind parameters evolve as the plasma expands through the heliosphere. Though previous studies have applied collisional analysis to the temperature ratio between protons (ionized hydrogen) and α-particles (fully ionized helium), this is the first study to explore α-proton differential flow with collisional analysis. First, the mathematical model for the collisional analysis of differential flow was derived. Then, this model was applied to individual in-situ observations from Parker Solar Probe (PSP; r = 0.1–0.27 au) to generate predictions of the α-proton differential flow in the near-Earth solar wind. A comparison of these predicted values with contemporaneous measurements from the Wind spacecraft (r = 1.0 au) shows strong agreement, which may imply that the effects of expansion and Coulomb collisions have a large role in governing the evolution of differential flow through the inner heliosphere.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"17 22","pages":""},"PeriodicalIF":3.0,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139443512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Forecasting solar flares with a transformer network","authors":"Keahi Pelkum Donahue, Fadil Inceoglu","doi":"10.3389/fspas.2023.1298609","DOIUrl":"https://doi.org/10.3389/fspas.2023.1298609","url":null,"abstract":"Space weather phenomena, including solar flares and coronal mass ejections, have significant influence on Earth. These events can cause satellite orbital decay due to heat-induced atmospheric expansion, disruption of GPS navigation and telecommunications systems, damage to satellites, and widespread power blackouts. The potential of flares and associated events to damage technology and disrupt human activities motivates prediction development. We use Transformer networks to predict whether an active region (AR) will release a flare of a specific class within the next 24 h. Two cases are considered: ≥C-class and ≥M-class. For each prediction case, separate models are developed. We train the Transformer to use time-series data to classify 24- or 48-h sequences of data. The sequences consist of 18 physical parameters that characterize an AR from the Space-weather HMI Active Region Patches data product. Flare event information is obtained from the Geostationary Operational Environmental Satellite flare catalog. Our model outperforms a prior study that similarly used only 24 h of data for the ≥C-class case and performs slightly worse for the ≥M-class case. When compared to studies that used a larger time window or additional data such as flare history, results are comparable. Using less data is conducive to platforms with limited storage, on which we plan to eventually deploy this algorithm.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"1 1","pages":""},"PeriodicalIF":3.0,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139446885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coherence of Elsässer Variables in the slow solar wind from 0.1 au to 0.3 au","authors":"Honghong Wu, Liping Yang, Shiyong Huang","doi":"10.3389/fspas.2023.1329284","DOIUrl":"https://doi.org/10.3389/fspas.2023.1329284","url":null,"abstract":"The highly Alfvénic fluctuations (AF) and magnetic-velocity alignment structures (MVAS) are two distinguished components in the near-Sun slow solar wind observed by Parker Solar Probe. The amplitudes of the Elsässer Variables z± of AF and MVAS show distinct features. However, how these fluctuations contribute to the slow solar wind turbulence remains unknown. Here we investigate the coherence between z+ and z− for the first time using the Parker Solar Probe measurements with a high resolution 0.8738 s in the slow solar wind from 0.1–0.3 au. We find that the coherence spectra of z+ and z− in the perpendicular directions for MVAS are remarkable higher than that for AF, in particular at large scale. There exists a break around 10 di (di is the ion inertial length) where the coherence decreases to a lower level for MVAS. A bump around 10 di appears on the coherence spectra of all three components for AF. The coherence of z+ and z− may relate to the possible nonlinear interactions reflected by the time series, the power spectra, and the self-correlation functions. These results help to understand the roles of AF and MVAS in the slow solar wind turbulence.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"13 2","pages":""},"PeriodicalIF":3.0,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139446880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sun-as-a-star variability of Hα and Ca II 854.2 nm lines","authors":"Garrett Zills, Serena Criscuoli, L. Bertello, Alexei Pevtsov","doi":"10.3389/fspas.2023.1328364","DOIUrl":"https://doi.org/10.3389/fspas.2023.1328364","url":null,"abstract":"Studies of stellar magnetic fields mostly rely on proxies derived from chromospheric lines, typically forming in the UV and shorter wavelengths and therefore accessible only from space based observatories. Even Ca II K or H observations, forming in regions accessible from the ground, are not always available. As a result, there is a crucial need to explore alternative activity proxies to overcome the limitations posed by observational constraints. Using sun-as-a-star observations acquired with the ISS at SOLIS we investigated the correlation between the Ca II K emission index and indices derived from the Hα 656.3 nm and Ca II 854.2 nm lines, which are well known chromospheric diagnostics. We found that both the core intensities and widths of the two lines are positively correlated with the Ca II K emission index (ρ ≳ 0.8), indicating their suitability as reliable indicators of magnetic activity, the width of the Hα line showing the highest correlation (ρ = 0.9). We also found that such correlations vary with the activity cycle. Specifically, during the analyzed cycle 24, the correlations with the Ca II K index varied 14% for the Hα width, 33% for the Hα core intensity, and doubled for the two Ca II 854.2 nm line indices. These results suggest that, among the investigated indices, the Hα width best traces magnetic activity. Results are discussed at the light of current knowledge of the formation heights of the two lines, and of spatially resolved solar observations.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"6 3","pages":""},"PeriodicalIF":3.0,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139445357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultra-broadband infrared metamaterial absorber based on MDMDM structure for optical sensing","authors":"Fengjie Li, Jiansen Du, Shang Wang, Ruitao Yu, Xi Wang, Tiqiang Zhang, Zongtao Chi, Bin Wang, Ning Li","doi":"10.3389/fspas.2023.1338284","DOIUrl":"https://doi.org/10.3389/fspas.2023.1338284","url":null,"abstract":"Infrared observation is a crucial tool in the study of astronomical celestial bodies. Metamaterials have a vast prospect for applications in the field of optics due to their unique electromagnetic tunable characteristics. In order to obtain an ultra-broadband high absorption material in the infrared region, we proposed a metal-dielectric-metal-dielectric-metal (MDMDM) metamaterial absorber using a titanium (Ti) nano-cross layer based on surface plasmon polariton (SPP) resonance and magnetic resonance cavity principles. The geometrical parameters of each layer have been examined carefully. The influence of incident angle from 0° to 60° is investigated for transverse electric and transverse magnetic plane-waves. Near-perfect absorption performance is achieved from near-infrared to mid-infrared region. The average absorption reaches as high as 97.41% from 2.05 to 6.08 μm. The absorber exhibits polarization-sensitive characteristics. The absorption peaks are 99.50% and 99.80% at 2.55 and 5.24 μm, respectively. The proposed material has potential applications in astronomical imaging, volcano and fire detection, remote sensing, biological monitoring, and other optical devices.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"2 5","pages":""},"PeriodicalIF":3.0,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139381181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}