Habitable Planets Research Articles

The impact of sustainable design and construction upon FM: four case studies

Purpose This paper aims to analyze the impact of sustainability measures taken during the design and construction phases, by examining two categories of sustainability: energy efficiency and reducing carbon emissions and material selection and waste management. These aspects are examined from the perspectives of long-term building performance and maintenance practices, as well as user/tenant satisfaction. Design/methodology/approach This study includes a literature review related to the two topics under consideration, followed by a comparative case study analysis of four projects to determine practical validity. All case studies in this paper used a semi-structured survey with various project stakeholders, which helped the authors identify measures taken as well as obstacles and challenges during the process. Findings According to the four case studies, adequate attention should be paid to the two areas of interest during a project’s design and construction phases. Including case studies from around the world (four case studies from three different countries) offers insights into effective sustainability practices in building design and construction, providing instances of successful implementation and emphasizing the obstacles and potential when incorporating sustainability into the design and construction phases. Research limitations/implications The findings also show that design and construction participants and companies should reduce waste generation and carbon emissions. In addition, they should make decisions on material selection to enhance projects’ sustainability and to contribute to creating a habitable planet for the future. Originality/value The influence of the design and construction phases on long-term project sustainability is of major importance and concern to users, owners, designers, contractors and facility managers. This study illustrates the necessity of including sustainability measures in the design and construction phases, highlighting the importance of sustainability in building design and construction through effective implementation techniques and interdisciplinary teamwork to realize sustainable goals.

Novel Atmospheric Dynamics Shape the Inner Edge of the Habitable Zone around White Dwarfs

White dwarfs offer a unique opportunity to search nearby stellar systems for signs of life, but the habitable zone around these stars is still poorly understood. Since white dwarfs are compact stars with low luminosity, any planets in their habitable zone should be tidally locked, like planets around M dwarfs. Unlike planets around M dwarfs, however, habitable white dwarf planets have to rotate very rapidly, with orbital periods ranging from hours to several days. Here we use the ExoCAM global climate model to investigate the inner edge of the habitable zone around white dwarfs. Our simulations show habitable planets with ultrashort orbital periods (P ≲ 1 day) enter a “bat rotation” regime, which differs from typical atmospheric circulation regimes around M dwarfs. Bat rotators feature mean equatorial subrotation and a displacement of the surface’s hottest regions from the equator toward the midlatitudes. We qualitatively explain the onset of bat rotation using shallow water theory. The resulting circulation shifts increase the dayside cloud cover and decrease the stratospheric water vapor, expanding the white dwarf habitable zone by ∼50% compared to estimates based on 1D models. The James Webb Space Telescope should be able to quickly characterize bat rotators around nearby white dwarfs thanks to their distinct thermal phase curves. Our work underlines that tidally locked planets on ultrashort orbits may exhibit unique atmospheric dynamics, and guides future habitability studies of white dwarf systems.

How black hole activity may influence exoplanetary evolution in our Galaxy

ABSTRACT An increasing number of exoplanets have been discovered in the Milky Way galaxy, which is also known to harbour a super-massive black hole (Sagittarius A*) at its centre. Here, we investigate how the central black hole (BH) activity may affect the evolution of exoplanets in our Galaxy. Accreting BHs emit high-energy radiation – extreme ultraviolet and X-rays – which can lead to XUV photoevaporation of the planetary atmospheres. We evaluate the atmospheric mass-loss using both theoretical estimates of the BH radiative output and observational constraints on the past activity history of Sgr A*. The resulting mass-loss is analysed as a function of the galactocentric distance. For the first time, we compute the exoplanet atmospheric evolution under BH irradiation by explicitly including the temporal evolution of the central luminosity output (i.e. the BH activity history). We obtain that Sgr A* could have a major impact on exoplanets located in the inner region of the Galaxy (e.g. Galactic bulge); a significant fraction of the atmospheric mass can be removed by BH irradiation; and in extreme cases, the initial atmosphere may be completely stripped away. Such mass-loss can have important consequences on the atmospheric chemistry and potential biological evolution. We discuss the physical implications for planetary habitability, and we also briefly consider the case of stellar-mass BHs. Overall, accreting black holes may play a significant role in the evolution of exoplanets in our Galaxy across cosmic time.

Stellar flares are far-ultraviolet luminous

ABSTRACT We identify 182 flares on 158 stars within 100 pc of the Sun in both the near-ultraviolet (NUV; $1750\!-\!2750$ Å) and far-ultraviolet (FUV; $1350\!-\!1750$ Å) using high-cadence light curves from the Galaxy Evolution Explorer. Ultraviolet (UV) emission from stellar flares plays a crucial role in determining the habitability of exoplanetary systems. However, whether such UV emission promotes or threatens such life depends strongly on the energetics of these flares. Most studies assessing the effect of flares on planetary habitability assume a 9000 K blackbody spectral energy distribution that produces more NUV flux than FUV flux ($\mathcal {R} \equiv F_{\rm FUV} / F_{\rm NUV} \approx \frac{1}{6}$). Instead, we observe the opposite with the excess FUV reaching $\mathcal {R} \approx \frac{1}{2}\!-\!2$, roughly $3\!-\!12$ times the expectation of a 9000 K blackbody. The ratio of FUV to NUV time-integrated flare energies is 3.0 times higher on average than would be predicted by a constant 9000 K blackbody during the flare. Finally, we find that the FUV/NUV ratio at peak tentatively correlates (${\sim} 2 \sigma$ significance) both with total UV flare energy and with the G − RP colour of the host star. On average, we observe higher FUV/NUV ratios at peak in $E_{\text{UV}}\gt 10^{32}$ erg flares and in flares on fully convective stars.

Habitability of an exoplanet based on stellar wind

This paper aims to investigate the influence of stellar winds on the atmosphere of exoplanets. Stellar winds, which consist of charged particles produced by stars, can heavily alter and affect the evolution and composition of exoplanet atmospheres. This paper will provide an overview of stellar wind characteristics and their interactions with exoplanets. It will also investigate the consequences of such interactions, such as atmospheric erosion, atmospheric escape, and the exoplanets habitability. In order to develop a more sophisticated and accurate method for identifying habitable planets that may host life, it is necessary to better understand the mechanisms of stellar wind to build more accurate models of stellar wind.

Toward a Natural History of Microbial Life

For most of Earth's history life was microbial, with archaeal and bacterial cells mediating biogeochemical cycles through their metabolisms and ecologies. This diversity was sufficient to maintain a habitable planet across dramatic environmental transitions during the Archean and Proterozoic Eons. However, our knowledge of the first 3 billion years of the biosphere pales in comparison to the rich narrative of complex life documented through the Phanerozoic geological record. In this review, we attempt to lay out a microbial natural history framework that highlights recent and ongoing research unifying microbiology, geochemistry, and traditional organismal evolutionary biology, and we propose six broadly applicable principles to aid in these endeavors. In this way, the evolutionary history of microbial life—once considered only a prelude to the much more storied history of complex metazoan life in the Phanerozoic—is finally coming into its own. ▪The outlines of microbial natural history are now starting to appear through the integration of genomic and geological records.▪Microorganisms drive Earth's biogeochemical cycles, and their natural history reflects a coevolution with the planet.▪Past environmental changes have induced microbial biotic transitions, marked by extinction, taxonomic shifts, and new metabolisms and ecologies.▪Microbial evolution can benefit from a historical perspective of processes and successions as established by macropaleontology.

Recurrent planetesimal formation in an outer part of the early solar system

The formation of planets in our solar system encompassed various stages of accretion of planetesimals that formed in the protoplanetary disk within the first few million years at different distances to the sun. Their chemical diversity is reflected by compositionally variable meteorite groups from different parent bodies. There is general consensus that their formation location is roughly constrained by a dichotomy of nucleosynthetic isotope anomalies, relating carbonaceous (C) meteorite parent bodies to the outer protoplanetary disk and the non-carbonaceous (NC) parent bodies to an origin closer to the sun. It is a common idea, that in these inner parts of the protoplanetary disks, planetesimal accretion processes were faster. Testing such scenarios requires constraining formation ages of meteorite parent bodies. Although isotopic age dating can yield precise formation ages of individual mineral constituents of meteorites, such ages frequently represent mineral cooling ages that can postdate planetesimal formation by millions or tens of millions of years, depending on the cooling history of individual planetesimals at different depths. Nevertheless, such cooling ages provide a detailed thermal history which can be fitted by thermal evolution models that constrain the formation age of individual parent bodies. Here we apply state-of-the-art thermal evolution models to constrain planetesimal formation times particular in the outer solar system formation region of C meteorites. We infer a temporally distributed accretion of various parent bodies from <0.6\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$<0.6$$\\end{document} Ma to ≈4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\approx 4$$\\end{document} Ma after solar system formation, with 3.7 Ma and 2.5-2.75\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$2.5-2.75$$\\end{document} Ma for the parent bodies of CR1-3 chondrites and the Flensburg carbonaceous chondrite, and <0.6\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$<0.6$$\\end{document} and <0.7\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$<0.7$$\\end{document} Ma for the parent bodies of differentiated achondrites NWA 6704 and NWA 011, respectively. This implies that accretion processes in the C reservoir started as early as in the NC reservoir and were operating throughout typical protoplanetary disk lifetimes, thereby producing differentiated parent bodies with carbonaceous compositions in addition to undifferentiated C chondrite parent bodies. The accretion times correlate inversely with the degree of the meteorites’ alteration, metamorphism, or differentiation. The accretion times for the CM, CI, Ryugu, and Tafassite parent bodies of 3.8 Ma, 3.8 Ma, 1-3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$1-3$$\\end{document} Ma, and 1.1 Ma, respectively, fit well into this correlation in agreement with the thermal and alteration conditions suggested by these meteorites. Our results indicate that individual planetesimals formed rapidly (i.e., within <1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$<1$$\\end{document} Ma), however, distinct planetesimals formed recurrently throughout the total lifetime of the protoplanetary disk. Rapid individual formation is consistent with streaming instabilities assisted by gravitational collapse. However, obviously not the total dust inventory was consumed at early disk evolution stages, so there must have been some delay mechanisms, e.g. collisional destruction of precursor aggregates due to high impact velocities induced by radial drift phenomena. This counterbalance enabled late (>2-3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$>2-3$$\\end{document} Ma) accretion of C planetesimals beyond the snow line which escaped severe planetesimal heating and volatile loss, hence, preserving their volatiles, especially water. Only this delayed formation of water-rich planetesimals allowed Earth to accrete sufficient water to become a habitable planet, preventing it from being a bone dry planet.

A New Lever on Exoplanetary B Fields: Measuring Heavy Ion Velocities

Magnetic fields connect an array of planetary processes, from atmospheric escape to interior convection. Despite their importance, exoplanet magnetic fields are largely unconstrained by both theory and observation. In this Letter, we propose a novel method for constraining the B field strength of hot gas giants: comparing the velocities of heavy ions and neutral gas with high-resolution spectroscopy. The core concept of this method is that ions are directly deflected by magnetic fields. While neutrals are also affected by B fields via friction with field-accelerated ions, ionic gas should be more strongly coupled to the underlying magnetic field than bulk neutral flow. Hence, measuring the difference between the two velocities yields rough constraints on the B field, provided an estimate of the stellar UV flux is known. We demonstrate that heavy ions are particularly well suited for this technique because they are less likely to be entrained in complex hydrodynamic outflows than their lighter counterparts. We perform a proof-of-concept calculation with Ba ii, an ion whose velocity has been repeatedly measured at high confidence with high-resolution spectroscopy. Our work shows that a 10 G magnetic field would produce ∼1 km s−1 ion–neutral velocity differences at a microbar, whereas a 50 G magnetic field would produce ∼20 km s−1 velocity difference. With new leverage on magnetic fields, we will be able to investigate magnetic field generation in the extreme edge cases of hot gas giants, with wide-ranging consequences for planetary interior structure, dynamo theory, and habitability.

Opportunities and Challenges in the Study of Exoplanetary Atmospheres during the JWST Era

Currently, more than 5 000 exoplanets have been detected, and exoplanetary science is evolving from a focus on exoplanet detection to a focus on comprehensive exoplanetary characterization. Over the past 20 years, through the atmospheric characterization of about 100 exoplanets, a basic framework has been established for atmospheric detection methods, a series of atmospheric spectral forward modeling and retrieval methods, and atmospheric theory for transiting and directly imaged planets. The James Webb Space Telescope (JWST) has unprecedented detection capabilities in the near to mid-infrared spectra, and high-quality data will drive the development of atmospheric theory and models. The early released scientific results of Cycle-1 have shown the ability of JWST to characterize the atmospheres of transiting and directly imaged exoplanets, as well as the initial constraints on the atmospheres of potentially habitable planets around nearby low-mass star. The pursuit of finely detailed exoplanet atmospheric characterization in the era of JWST has already begun, and in conjunction with future missions with atmospheric survey capabilities, such as ARIEL (Atmospheric Remote-sensing Infrared Exoplanet Large-survey) and large-aperture adaptive-optics ground-based telescopes in the next 5 years, will reveal the diversity of exoplanet atmospheres at a much deeper level.

SPHERE RefPlanets: Search for ε Eridani b and warm dust

Context. Cold planets, including all habitable planets, produce only scattered light emission in the visual to near-infrared wavelength range. For this reason it is highly desirable to adapt the technique for the direct imaging of reflected light from extra-solar planets. Aims. For the nearby system ε Eri, we want to set much deeper detection limits for the expected scattered radiation from the radial velocity planet candidate (≈0.7 MJ) and the warm dust using the VLT/SPHERE adaptive optics (AO) instrument with the ZIMPOL imaging polarimeter. Methods. We carried out very deep imaging polarimetry of ε Eri based on 38.5 h of integration time with a broad-band filter (λc = 735 nm) for the search of the polarization signal from a planet or from circumstellar dust using AO, coronagraphy, high precision differential polarimetry, and angular differential imaging. The data were collected during 12 nights within four epochs distributed over 14 months and we searched for a signal in the individual epochs. We also combined the full data set to achieve an even higher contrast limit considering the Keplerian motion using the K-Stacker software. All data were also combined for the search of the scattering signal from extended dust clouds. We improved various data reduction and post-processing procedures and also developed new ones to enhance the sensitivity of SPHERE/ZIMPOL further. The final detection limits were quantified and we investigated the potential of SPHERE/ZIMPOL for deeper observations. Results. The data of ε Eridani provide unprecedented contrast limits but no significant detection of a point source or an extended signal from circumstellar dust. For each observing epoch, we achieved a 5 σ𝒩 point source contrast for the polarized intensity CP = Qϕ/I★ between 2 × 10−8 and 4 × 10−8 at a separation of ρ ≈ 1″, which is as expected for the proposed radial velocity planet at a quadrature phase. The polarimetric contrast limits are close to the photon noise limits for ρ &gt; 0.6″ or about six times to 50 times better than the intensity limits because polarimetric imaging is much more efficient for speckle suppression. Combining the data for the search of a planet moving on a Keplerian orbit with the K-Stacker technique improves the contrast limits further by about a factor of two, when compared to an epoch, to about CP = 0.8 × 10−8 at ρ = 1″. This would allow the detection of a planet with a radius of about 2.5 RJ. Should future astrometry provide strong constraints on the position of the planet, then a 3 σ𝒩 detection at 1″ with CP ≈ 5 × 10−9 would be within reach of our data. The surface brightness contrast limits achieved for the polarized intensity from an extended scattering region is about 15 mag arcsec−2 at 1″ or up to 3 mag arcsec−2 deeper than previous limits. For ε Eri, these limits exclude the presence of a narrow dust ring and they constrain the dust properties. The photon statistics would allow deeper limits but we find a very weak systematic noise pattern probably introduced by polarimetric calibration errors. Conclusions. This ε Eri study shows that the polarimetric contrast limits for reflecting planets with SPHERE/ZIMPOL can be improved to a level below Cp &lt; 10−8 by just collecting more data during many nights using software such as K-Stacker, which can combine all data considering the expected planet orbit. Contrast limits of Cp ≈ 10−9 are within reach for ε Eri if the search can be optimized for a planet with a well-known orbit. This limit is also attainable for other bright nearby stars, such as α Cen or Sirius A. Such data also provide unprecedented sensitivity for the search of extended polarized emission from warm circumstellar dust.

The Vulcan Mission to Io: Lessons Learned during the 2022 JPL Planetary Science Summer School

A mission to Jupiter's moon Io, the most volcanically active body in the solar system, was suggested as a priority for the New Frontiers program in the 2013 Planetary Science Decadal Survey. We present a New Frontiers–class mission concept, Vulcan, that was designed as an educational exercise through the Jet Propulsion Laboratory’s 2022 Planetary Science Summer School. Vulcan would leverage an instrument suite consisting of wide- and narrow-angle cameras, a thermal infrared spectrometer, two fluxgate magnetometers, and ion and electron electrostatic analyzers to conduct the most thorough investigation of Io to date. Using 78 flybys over a 2 yr primary science mission, Vulcan would characterize the effects of tidal forces on the differentiation state, crustal structure, and volcanism of Io and investigate potential interactions between Io's volcanoes, surface features, and atmosphere. Although Vulcan was developed as an academic exercise, we show that a New Frontiers–class mission to Io could achieve transformative science in both geophysics and plasma physics, unifying typically disparate subfields of planetary science. A dedicated mission to Io, in combination with the Europa Clipper and Jupiter Icy Moons Explorer missions, would address fundamental questions raised by the 2023 Planetary Science Decadal Survey and could complete our understanding of the spectrum of planetary habitability. Lessons learned from Vulcan could be applied to a New Frontiers 5 Io mission concept in the near future.

Atmospheric Escape From Earth and Mars: Response to Solar and Solar Wind Drivers of Oxygen Escape

AbstractHabitability at the surface of a planet depends on having an atmosphere long enough for life to develop. The loss of atmosphere to space is an important component in assessing planetary surface habitability. Current models of atmospheric escape from exoplanets are not well constrained by observations. Atmospheric escape observations from the terrestrial planets are available in public data archives. We recast oxygen escape rates from Earth derived from an instrument on Dynamics Explorer‐1 as function of solar wind and compare them to similar data from Mars. Analysis demonstrates that oxygen escape rates from Mars are not as sensitive to variations in solar power components as those from Earth. Available data from Venus can confirm or refute the assertion that oxygen escape from magnetized planets is more sensitive than that from unmagnetized planets.

Prospects for the characterization of habitable planets

Prospects for the characterization of habitable planets

Iron oxidation and porosity generation in serpentinized abyssal peridotite

Serpentinization, the water-driven alteration of olivine-rich rocks, is a fundamental process contributing to planetary habitability and the maintenance of rock-hosted life on Earth. Serpentinization generates molecular hydrogen via the reduction of water and the coupled oxidation of Fe, which partitions into serpentine, brucite and magnetite. Magnetite formation controls the magnetic properties of serpentinites, and researchers have highlighted a link between increasing magnetic susceptibility and decreasing density of peridotites with increasing degree of serpentinization. Several analytical and theoretical studies have suggested that these increases in magnetization and decreases in density are accompanied by increasing porosity. Here, we investigate the potential correlation between porosity generation and serpentinization by analyzing the geochemical composition, Fe redox state, and porosity of 28 abyssal serpentinites recovered via drilling from the Atlantic Ocean subseafloor. Principal component analysis applied to the resulting dataset revealed no direct links between these properties, which we suggest results from the introduction of variability due to low-temperature seafloor weathering processes. Seafloor weathering can modify the porosity of serpentinites by dissolving brucite, and it affects the Fe redox state of serpentinites by inducing the replacement of magnetite by Fe(III) minerals like maghemite, hematite, and goethite. Moreover, we also suggest that ophiolitic serpentinites would not show direct correlations between porosity and Fe redox state, due to geochemical transformations induced by metamorphism and porosity reworking linked to deformation induced by tectonic stresses. Ultimately, our results demonstrate that weathering processes can significantly affect the chemical and physical properties of serpentinites and thus must be considered in geochemical and geophysical evaluations of these rocks.

Responsible Artificial Intelligence for Climate Action: A Theoretical Framework for Sustainable Development

Climate change poses an urgent and significant challenge, with far-reaching impacts already affecting our planet, and projections indicating worsening conditions in the future. The concept of sustainable development aims to meet present needs while safeguarding the ability of future generations to meet their own requirements. However, climate change's effects on sustainable development are of paramount concern, as they amplify issues like poverty, food insecurity, and environmental degradation, affecting economic growth, social progress, and environmental protection. Taking immediate action to mitigate climate change and implement sustainable practices is crucial to ensuring a habitable planet for future generations. In this context, Responsible Artificial Intelligence (RAI) emerges as a promising direction, striving for ethical and responsible technology use in diverse sustainable development tasks. RAI proves to be a robust candidate for empowering climate change mitigation and adaptation efforts. This study introduces a theoretical RAI framework designed to support climate action by responsibly enabling more accurate predictions and analysis of climate data, enhancing energy efficiency, and reducing greenhouse gas emissions. The framework emphasizes the need for interdisciplinary collaboration among policymakers, scientists, and technicians to develop RAI solutions that advance sustainable development and alleviate the adverse impacts of climate change. Unlike previous works, this research presents a novel perspective on the principles of RAI that explicitly consider climate-related aspects. By laying the foundations of AI research to bolster our fight against climate change, this article establishes essential pillars that encourage further advancements in this critical endeavor.

Data-enhanced revealing of trends in Geoscience

Abstract Purpose This article presents an in-depth analysis of global research trends in Geosciences from 2014 to 2023. By integrating bibliometric analysis with expert insights from the Deeptime Digital Earth (DDE) initiative, this article identifies key emerging themes shaping the landscape of Earth Sciences①. Design/methodology/approach The identification process involved a meticulous analysis of over 400,000 papers from 466 Geosciences journals and approximately 5,800 papers from 93 interdisciplinary journals sourced from the Web of Science and Dimensions database. To map relationships between articles, citation networks were constructed, and spectral clustering algorithms were then employed to identify groups of related research, resulting in 407 clusters. Relevant research terms were extracted using the Log-Likelihood Ratio (LLR) algorithm, followed by statistical analyses on the volume of papers, average publication year, and average citation count within each cluster. Additionally, expert knowledge from DDE Scientific Committee was utilized to select top 30 trends based on their representation, relevance, and impact within Geosciences, and finalize naming of these top trends with consideration of the content and implications of the associated research. This comprehensive approach in systematically delineating and characterizing the trends in a way which is understandable to geoscientists. Findings Thirty significant trends were identified in the field of Geosciences, spanning five domains: deep space, deep time, deep Earth, habitable Earth, and big data. These topics reflect the latest trends and advancements in Geosciences and have the potential to address real-world problems that are closely related to society, science, and technology. Research limitations The analyzed data of this study only contain those were included in the Web of Science. Practical implications This study will strongly support the organizations and individual scientists to understand the modern frontier of earth science, especially on solid earth. The organizations such as the surveys or natural science fund could map out areas for future exploration and analyze the hot topics reference to this study. Originality/value This paper integrates bibliometric analysis with expert insights to highlight the most significant trends on earth science and reach the individual scientist and public by global voting.

Closeby Habitable Exoplanet Survey (CHES). I. Astrometric Noise and Planetary Detection Efficiency Due to Stellar Spots and Faculae

The Closeby Habitable Exoplanet Survey (CHES) is dedicated to the astrometric exploration for habitable-zone Earth-like planets orbiting solar-type stars in close proximity, achieving unprecedented microarcsecond precision. Given the elevated precision, meticulous consideration of photocenter jitters induced by stellar activity becomes imperative. This study endeavors to model the stellar activity of solar-type stars, compute astrometric noise, and delineate the detection limits of habitable planets within the astrometric domain. Simulations were conducted for identified primary targets of CHES, involving the generation of simulated observed data for astrometry and photometry, accounting for the impact of stellar activity. Estimation of activity levels in our sample was achieved through chromospheric activity indices, revealing that over 90% of the stars exhibited photocenter jitters below 1 μas. Notably, certain proximate stars, such as α Cen A and B, displayed more discernible noise arising from stellar activity. Subsequent tests were performed to evaluate detection performance, unveiling that stellar activity tends to have a less pronounced impact on planetary detectability for the majority of the stars. Approximately 95% of the targets demonstrated a detection efficiency exceeding 80%. However, for several cold stars, e.g., HD 32450 and HD 21531, with the habitable zones close to the stars, a reduction in detection efficiency was observed. These findings offer invaluable insights into the intricate interplay between stellar activity and astrometric precision, significantly advancing our understanding in the search for habitable planets.

Search for giant planets in M 67 V: A warm Jupiter orbiting the turn-off star S1429

Context. Planets orbiting members of open or globular clusters offer a great opportunity to study exoplanet populations systematically, as stars within clusters provide a mostly homogeneous sample, at least in chemical composition and stellar age. However, even though there have been coordinated efforts to search for exoplanets in stellar clusters, only a small number of planets have been detected. One successful example is the seven-year radial velocity (RV) survey ‘Search for giant planets in M 67’ of 88 stars in the open cluster M 67, which led to the discovery of five giant planets, including three close-in (P &lt; 10 days) hot-Jupiters. Aims. In this work, we continue and extend the observation of stars in M 67, with the aim being to search for additional planets. Methods. We conducted spectroscopic observations with the Habitable Planet Finder (HPF), HARPS, HARPS-North, and SOPHIE spectrographs of 11 stars in M 67. Six of our targets showed a variation or long-term trends in their RV during the original survey, while the other five were not observed in the original sample, bringing the total number of stars to 93. Results. An analysis of the RVs reveals one additional planet around the turn-off point star S1429 and provides solutions for the orbits of stellar companions around S2207 and YBP2018. S1429 b is a warm-Jupiter on a likely circular orbit with a period of $\[\77.48_{-0.19}^{+0.18}\]$ days and a minimum mass of M sin i = 1.80 ± 0.2 MJ. We update the hot-Jupiter occurrence rate in M 67 to include the five new stars, deriving $\[\4.2_{-2.3}^{+4.1} \%\]$ when considering all stars, and $\[\5.4_{-3.0}^{+5.1} \%\]$ if binary star systems are removed.

Marine Science Can Contribute to the Search for Extra-Terrestrial Life.

Life on our planet likely evolved in the ocean, and thus exo-oceans are key habitats to search for extraterrestrial life. We conducted a data-driven bibliographic survey on the astrobiology literature to identify emerging research trends with marine science for future synergies in the exploration for extraterrestrial life in exo-oceans. Based on search queries, we identified 2592 published items since 1963. The current literature falls into three major groups of terms focusing on (1) the search for life on Mars, (2) astrobiology within our Solar System with reference to icy moons and their exo-oceans, and (3) astronomical and biological parameters for planetary habitability. We also identified that the most prominent research keywords form three key-groups focusing on (1) using terrestrial environments as proxies for Martian environments, centred on extremophiles and biosignatures, (2) habitable zones outside of "Goldilocks" orbital ranges, centred on ice planets, and (3) the atmosphere, magnetic field, and geology in relation to planets' habitable conditions, centred on water-based oceans.

Setting the Stage for the Search for Life with the Habitable Worlds Observatory: Properties of 164 Promising Planet-survey Targets

The Decadal Survey on Astronomy and Astrophysics 2020 has recommended that NASA realize a large IR/optical/UV space telescope optimized for high-contrast imaging and spectroscopy of ∼25 exo-Earths and transformative general astrophysics. The NASA Exoplanet Exploration Program (ExEP) has subsequently released a list of 164 nearby (d < 25 pc) targets deemed the most accessible to survey for potentially habitable exoplanets with the Habitable Worlds Observatory (HWO). We present a catalog of system properties for the 164 ExEP targets, including 1744 abundance measurements for 14 elements from the Hypatia Catalog and 924 photometry measurements spanning from 151.6 nm to 22 μm in the GALEX, Strömgren, Tycho, Gaia, Two Micron All Sky Survey, and Wide-field Infrared Survey Explorer bandpasses. We independently derive stellar properties for these systems by modeling their spectral energy distributions with Bayesian model averaging. Additionally, by consulting the literature, we identify TESS flare rates for 46 stars, optical variability for 78 stars, and X-ray emission for 46 stars in our sample. We discuss our catalog in the context of planet habitability and draw attention to key gaps in our knowledge where precursor science can help to inform HWO mission design trade studies in the near future. Notably, only 33 of the 164 stars in our sample have reliable space-based UV measurements, and only 40 have a mid-IR measurement. We also find that phosphorus, a bioessential element, has only been measured in 11 of these stars, motivating future abundance surveys. Our catalog is publicly available and we advocate for its use in future studies of promising HWO targets.