MINDS: The JWST MIRI Mid-INfrared Disk Survey

Publications of the Astronomical Society of the Pacific, Journal Year: 2024, Volume and Issue: 136(5), P. 054302 - 054302

Published: May 1, 2024

Abstract The study of protoplanetary disks has become increasingly important with the Kepler satellite finding that exoplanets are ubiquitous around stars in our galaxy and discovery enormous diversity planetary system architectures planet properties. High-resolution near-IR ALMA images show strong evidence for ongoing formation young disks. JWST MIRI mid-INfrared Disk Survey (MINDS) aims to (1) investigate chemical inventory terrestrial planet-forming zone across stellar spectral type, (2) follow gas evolution into disk dispersal stage, (3) structure debris thermal mid-IR. MINDS survey will thus build a bridge between properties exoplanets. comprises 52 targets (Herbig Ae stars, T Tauri very low-mass disks). We primarily obtain MIRI/MRS spectra high signal-to-noise ratio (∼100–500) covering complete wavelength range from 4.9 27.9 μ m. For handful selected we also NIRSpec IFU resolution spectroscopy (2.87–5.27 m). search signposts emission micron-sized dust—information complementary scattered light small dust grains large submillimeter domain. spatial three key systems have shown formation, TW Hya HD 169142 using coronagraph at 15.5 m 10.65 respectively PDS 70 NIRCam imaging 1.87 narrow 4.8 medium band filter. provide here an overview showcase power new mid-IR molecular spectrum where report detection ion CH 3 + robust confirmation HCO + earlier detected Spitzer.

Language: Английский

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Enough Sulfur and Iron for Potential Life Make Enceladus’s Ocean Fully Habitable

The Astrophysical Journal Letters, Journal Year: 2025, Volume and Issue: 980(1), P. L10 - L10

Published: Feb. 6, 2025

Abstract The Cassini spacecraft revealed life-forming elements like CHNOP and diverse organic compounds from Enceladus’s ocean. However, the availability of minor but bio-essential nutrients such as iron sulfur remains unknown. Here, we perform geochemical modeling to explore their chemistry in We find that dissolved predominantly occurs Fe( ii ) with a solubility ranging 10 −8 −5 mole (kg H 2 O) −1 (decreasing increasing pH). Dissolved sulfur, mainly present HS − , is predicted have concentration −6 −4 pH has only effect on S solubility. Our availabilities Fe are close measured concentrations inhabited terrestrial serpentinization fluids, implying sufficient support potential life. results also suggest reduction ferric or sulfate might supply enough energy for chemotrophic metabolisms based these reactions complement previously proposed methanogenesis. levels bioproductivity supported by overall lower than those sustained other nutrients, still orders magnitude higher maximum level estimated chemical energy.

Language: Английский

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Clay minerals on Mars: An up-to-date review with future perspectives

Earth-Science Reviews, Journal Year: 2023, Volume and Issue: 243, P. 104491 - 104491

Published: June 26, 2023

Language: Английский

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Evidence for Nitrogen-bearing Species on Umbriel: Sourced from a Subsurface Ocean, Undifferentiated Crust, or Impactors?

The Planetary Science Journal, Journal Year: 2023, Volume and Issue: 4(3), P. 42 - 42

Published: March 1, 2023

Abstract Near-infrared spectra of Umbriel and the other classical Uranian moons exhibit 2.2 μ m absorption bands that could result from ammonia (NH 3 ) bearing species, possibly exposed in geologically recent past. However, has an ancient surface with minimal evidence for endogenic activity, raising possibility more refractory species are present, and/or NH is retained over long timescales. We analyzed 33 to investigate its band, along three features we identified near 2.14, 2.22, 2.24 m. assessed subobserver longitudinal distributions these four bands, finding they present across may be spatially associated geologic such as craters large basins. compared 15 candidate constituents. found Umbriel’s 2.14 2.22 most consistent spectral signature organics, band best matched by ice, signatures –H 2 O mixtures, aluminum-bearing phyllosilicates, sodium-bearing carbonates. some constituents do not match properties wavelength regions, highlighting gaps our understanding moons’ compositions. alternatively a ν overtone mode CO ice. If on Umbriel, have formed contact internal ocean were subsequently during early history. Alternatively, might originated undifferentiated crust or delivered impactors.

Language: Английский

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The Winchcombe fireball—That lucky survivor

Meteoritics and Planetary Science, Journal Year: 2023, Volume and Issue: 59(5), P. 927 - 947

Published: May 10, 2023

Abstract On February 28, 2021, a fireball dropped ∼0.6 kg of recovered CM2 carbonaceous chondrite meteorites in South‐West England near the town Winchcombe. We reconstruct fireball's atmospheric trajectory, light curve, fragmentation behavior, and pre‐atmospheric orbit from optical records contributed by five networks. The progenitor meteoroid was three orders magnitude less massive (∼13 kg) than any previously observed fall. Winchcombe meteorite survived entry because it exposed to very low peak dynamic pressure (∼0.6 MPa) due fortuitous combination parameters, notably velocity (13.9 km s −1 ). A near‐catastrophic at ∼0.07 MPa points body's fragility. Low speeds which cause pressures are likely necessary conditions for small survive entry, strongly constraining radiant direction general antapex direction. Orbital integrations show that injected into near‐Earth region ∼0.08 Myr ago never had perihelion distance smaller ∼0.7 AU, while other with known orbits approached Sun closer (∼0.5 AU) were heated least 100 K higher temperatures.

Language: Английский

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The mineralogy and alteration history of the Yamato-type (CY) carbonaceous chondrites

Geochimica et Cosmochimica Acta, Journal Year: 2023, Volume and Issue: 361, P. 245 - 264

Published: Sept. 30, 2023

The CY chondrites are a group of thermally metamorphosed carbonaceous chondrites. Although they share similarities with the CM and CI chondrites, their primary properties argue for distinct classification. Previous studies have highlighted isotopically heavy bulk compositions (δ17O=10 ‰, δ18O=21 Δ17O=0 ‰) exceptionally high sulphide abundances (10-30 vol%). In this work we explore petrography alteration history. CYs accreted low chondrules (15-20 area%) average apparent diameters slightly larger (∼320-340 µm) than contrast to CMs, record an early episode brecciation prior main window aqueous alteration. Subsequent fluid activity produced range extents both CY2 CY1 documented. Phyllosilicate minerals in were mix serpentine saponite (including occurrences Na-saponite) minor quantities chlorite (within chondrules). An initial generation Fe-sulphides formed by sulfidation metal, precipitation from S-rich fluids. Three generations carbonates recognized, that infilled voids left co-precipitated sulphide, later magnetite final Fe-Mg-bearing which large (>100 clasts. Only first-generation found CY2s, while CY1s preserve all three generations. Phosphates occur as Ca-apatite or rarely Mg-apatite hydroxylapatite compositions, indicating halogen activities Refractory oxides (ilmenite Cr-spinel) precipitates adhering margins phyllosilicates. They late sequence attest oxidizing conditions. During late-stages replaced magnetite. Thermal metamorphism (Stage II-IV: ∼300-750 °C) overprinted leading dehydration recrystallization phyllosilicate matrix decomposition some carbonate phases. Most Fe-sulphide grains survived heating without partial pyrrhotite troilite under closed system conditions led elevated ƒS2 gas resulted stabilizing effect. Retrograde reactions between trapped S2 metal/magnetite Fe-sulphides. survival stochiometric evidence near-closed heating. Analysis organic matter Raman spectroscopy supports interpretation short-duration (on scale minutes days), at peak temperatures 750-900 °C. Thus, impact event was most likely cause metamorphic

Language: Английский

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Clumped isotope and Δ17O measurements of carbonates in CM carbonaceous chondrites: New insights into parent body thermal and fluid evolution

Geochimica et Cosmochimica Acta, Journal Year: 2024, Volume and Issue: 369, P. 1 - 16

Published: Jan. 28, 2024

The CM carbonaceous chondrites are key archives for understanding the earliest history of solar system. Their C-complex asteroid parent body(ies) underwent aqueous alteration, among products which carbonate minerals that can faithfully record conditions their formation. In this study we report carbon, triple oxygen and clumped isotope compositions carbonates in six span a range degrees alteration (Allan Hills 83100, Cold Bokkeveld, LaPaz Icefield 031166, Lonewolf Nunataks 94101, Murchison, Scott Glacier 06043). Δ17O values from -1 to -2.6‰ (±0.1), where calcite dolomite co-exist differ by 0.6 permil, suggesting precipitation distinct fluids. Calculated crystallization temperatures 5 51⁰C (typically ±10⁰C) 75 101(±15)⁰C dolomite. δ18OVSMOW fluids they formed ranges -6.6 2.3‰, with no relationship δ13C carbonates. As population any one chondrite include multiple generations grains at different conditions, these represent mode temperature formation each meteorite. We observe more altered meteorites lower higher. These correlations consistent being prograde reaction whereby hotter had undergone greater exchange anhydrous matrix. Our data broadly closed system model water/rock interaction, but mineral latter stages may be linked fluid movement via fractures.

Language: Английский

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High surface area and interconnected nanoporosity of clay-rich astromaterials

Scientific Reports, Journal Year: 2024, Volume and Issue: 14(1)

Published: May 6, 2024

Abstract Porosity affects key astromaterial processes from disruption in our atmosphere and impact with the ground, to comminution of boulders by thermal slope mechanics on asteroid surfaces, access utilization in-situ resources. Whereas bulk porosity clay-rich meteorites is well established, magnitude their surface area nano-scale poorly known. Here we use N 2 BET gas adsorption measure specific nanoscale pore distribution several meteorites. Two recent falls Tarda (C2-ung) Aguas Zarcas (CM2) have areas 72.5 16.5 m /g, respectively. However, ranges 33.7 81.6 /g depending outgassing conditions. The dominated an interconnected network ~ 3-nm-sized pores, whereas shows a lower density 3 nm pores broader size around 40 nm. In contrast, Ivuna Orgueil (CI1) 15 18 /g: low values compared are likely due neoformation pore-blocking minerals during atmospheric exposure. These data suggest that returned samples asteroids Ryugu Bennu, which mineralogically texturally similar Tarda, also high area.

Language: Английский

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A sample preparation guide for clay‐rich carbonaceous chondrites

Meteoritics and Planetary Science, Journal Year: 2024, Volume and Issue: 59(3), P. 560 - 567

Published: Jan. 26, 2024

Abstract The matrix of the C2‐ungrouped Tarda meteorite contains abundant smectite minerals that swell and crumble when exposed to polar liquids, causing sample rapidly slake. This phenomenon presents a serious challenge polishing meteorite, as common liquids used on carbonaceous chondrites, such water, ethanol, ethylene glycol, isopropyl alcohol, are will cause swell, making it unsuitable for some analyses. Hexane mineral oil nonpolar were found not induce swelling highly expansive montmorillonite‐clay analog material effectively integrated into procedure Tarda. Here, we detail mounting, cutting, prepare surface is suitable variety sensitive techniques, electron microprobe analysis. work offers practical methodology preparation other clay‐rich samples, which may include recently returned Ryugu Bennu materials.

Language: Английский

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The Winchcombe meteorite—A regolith breccia from a rubble pile CM chondrite asteroid

Meteoritics and Planetary Science, Journal Year: 2022, Volume and Issue: 59(5), P. 1043 - 1067

Published: Dec. 21, 2022

Abstract The Winchcombe meteorite is a CM chondrite breccia composed of eight distinct lithological units plus cataclastic matrix. degree aqueous alteration varies between intensely altered CM2.0 and moderately CM2.6. Although no lithology dominates, three heavily rock types (CM2.1–2.3) represent >70 area%. Tochilinite–cronstedtite intergrowths (TCIs) are common in several lithologies. Their compositions can vary significantly, even within single lithology, which prevent clear assessment extent if only TCI composition considered. We suggest that this due to early under localized geochemical microenvironments creating diversity because later reprocessing was incomplete, leaving record the parent body's fluid history. In Winchcombe, fragments primary accretionary held matrix (~15 area%). This material impact‐derived fallback debris. Its grain size texture disruption original asteroid responded by intergranular fracture at sizes <100 μm, while larger phases, such as whole chondrules, splintered apart. Re‐accretion formed poorly lithified body. During atmospheric entry, meteoroid broke apart with new fractures preferentially cutting through weaker separating into its component clasts. strength imparts control on survival meteoroids. Winchcombe's unweathered state lithologies make it an ideal sample for exploring geological history group.

Language: Английский

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