NIRSpec Archives - Page 3 of 8 - Astrobiology

Schematic illustration of interstellar comet 3I/ATLAS showing the expected stratigraphy of an irradiated nucleus. Galactic cosmic ray irradiation over several Gyr alters the outer ∼15–20 m, producing a CO2-rich crust through CO-to-CO2 conversion, ongoing CO release from the breakdown of irradiated organics, an organic-rich refractory mantle with a red spectral slope, and compact amorphous ice characterized by low diffusivity and high thermal conductivity. Beneath this layer lies a pristine, unprocessed interior shielded from GCRs, whose composition and structure remain unknown but are expected to differ markedly from the irradiated crust. -- astro-ph.EP

Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Interstellar, Status Report

Interstellar Comet 3I/ATLAS: Evidence for Galactic Cosmic Ray Processing

by Keith CowingNovember 3, 2025November 3, 2025

Spectral observations of 3I/ATLAS (C/2025 N1) with JWST/NIRSpec and SPHEREx reveal an extreme CO2 enrichment (CO2/H2O = 7.6+-0.3) that is 4.5 sigma above solar system comet trends and among the […]

JWST NIRSpec PRISM transmission spectra compared with modeled atmospheric scenarios. The x-axis shows wavelengths in microns, while the y-axis shows the transit depth in parts per million. Each of the individual visits (translucent colored circles with error bars), the combination of visits 1 and 2 (gray circles with error bars), and the stellar-contamination-corrected four-visit spectrum from N. Espinoza et al. (2025; black circles with error bars) are compared to the HST data from J. de Wit et al. (2018; dark red stars with error bars). An array of forward-model spectra for different atmospheric scenarios is overlaid (colored lines). Atmospheric models rich in H2 can be easily ruled out, while many high mean molecular weight scenarios are consistent with the JWST data. -- IOPscience

Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Extremeophiles and Extreme Environments, Habitable Zones, Imaging & Spectroscopy, Status Report, TRAPPIST-1

JWST-TST DREAMS: Secondary Atmosphere Constraints for the Habitable Zone Planet TRAPPIST-1 e

by Keith CowingOctober 14, 2025October 14, 2025

The TRAPPIST-1 system offers one of the best opportunities to characterize temperate terrestrial planets beyond our own solar system.

H2 abundance constraints for TRAPPIST-1 e from HST and JWST as a function of surface pressure. Posterior distribution showcasing the improvement on constraints on possible H2-dominated atmospheres on TRAPPIST-1 e between HST (left in gray; obtained by applying our GP retrieval methodology to the HST/WFC3 data in Z. Zhang et al. 2018) and JWST (right in blue; obtained by applying it to the four NIRSpec/PRISM transits presented in this work). The distribution for HST mainly follows the centered log-ratio prior allowing the H2-dominated solution at virtually all pressures ≳1 bar; the JWST one disfavors the H2-dominated solution. -- IOPscience

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, TRAPPIST-1

JWST-TST DREAMS: NIRSpec/PRISM Transmission Spectroscopy of the Habitable Zone Planet TRAPPIST-1 e

by Keith CowingOctober 14, 2025October 14, 2025

TRAPPIST-1 e is one of the very few rocky exoplanets that is both amenable to atmospheric characterization and resides in the habitable zone of its star—located at a distance from […]

Optical depth spectra of the YSOs in our sample, shifted vertically for clarity. For illustration purposes, the red lines correspond to a linear combination of four ice mixtures selected from LIDA (3000 monolayers of pure H2O at a temperature of 15 K, H2O:CO2 in the ratio 10:1 at 10 K, CO:CO2 in the ratio 2:1 at 15 K, and pure OCS at 17 K) and provide a reasonable fit to the observations. The corresponding column densities are listed in Table 4. The legend at the top of each panel indicates the ice features discussed in the text and the corresponding wavelengths, to guide the eye. -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Biosignatures & Paleobiology, Icy Worlds, Imaging & Spectroscopy, Interstellar, Status Report

First Detection Of Ices In Intermediate-mass Young Stellar Objects Beyond The Milky Way

by Keith CowingSeptember 27, 2025September 27, 2025

Using NIRSpec on JWST, we studied a sample of 15 intermediate-mass (1.8-4.1 Msun) young stellar objects (YSOs) previously identified with MIRI photometry in the low-metallicity NGC 346 star-forming cluster in […]

MAP transmission spectra (R=500) for retrievals conducted with fixed Mp = 6.07M⊕, with a continuum constructed from Titan-like haze (K84; cyan) and ×1000Z⊙ haze case (H24; purple and red). -- astro-ph.EP

Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

Hydrocarbon Hazes On Temperate Sub-Neptune K2-18b Supported By Data From The James Webb Space Telescope

by Keith CowingSeptember 16, 2025September 16, 2025

K2-18b, a sub-Neptune orbiting in the habitable zone of an M dwarf, has attracted significant interest following observations with the Hubble Space Telescope (HST) and, more recently, with the James […]

The exoplanet TRAPPIST-1 d -- ESA

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release, TRAPPIST-1

There Is No Earth-like Atmosphere On TRAPPIST-1 d

by Keith CowingSeptember 5, 2025September 5, 2025

The exoplanet TRAPPIST-1 d intrigues astronomers looking for possibly habitable worlds beyond our solar system because it is similar in size to Earth, rocky, and resides in an area around […]

This artist’s concept depicts planet TRAPPIST-1 d passing in front of its turbulent star, with other members of the closely packed system shown in the background. Credit: NASA, ESA, CSA, J. Olmsted (STScI)

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release, TRAPPIST-1

Webb Narrows Atmospheric Possibilities For Earth-sized Exoplanet TRAPPIST-1 d

by Keith CowingAugust 13, 2025August 13, 2025

The exoplanet TRAPPIST-1 d intrigues astronomers looking for possibly habitable worlds beyond our solar system because it is similar in size to Earth, rocky, and resides in an area around […]

Joint posterior constraints on the surface partial pressure of key atmospheric absorbers for atmospheric scenarios similar to solar system terrestrials, with N2 as the background gas. The color shadings correspond to the posterior probability mass, and the contours highlight the 68% and 95% confidence regions from the joint retrieval in each case. The absorber in the N2-background atmosphere is labeled in the top right corner of each panel. The dashed-dotted, dashed, and solid sienna lines correspond to an atmospheric surface pressure of 0.1, 1, and 10 bar. We illustrate where typical models of Archean Earth (AE), Modern Earth (ME), and compositions for Titan (T), early Mars (eMa), Mars (Ma), and Venus (V; Encrenaz & Coustenis 2018) approximately lie relative to our constraints for TRAPPIST-1 d. Star markers correspond to specific cloudy cases, where the planet is modeled as either cloudy or cloud-free (for Titan, Modern Earth, and Venus). For the N2-H2O case, we show as a black dotted line the limit of pressures that would be cut off by refraction in a 11 bar atmosphere (10 bar H2O+1 bar N2). For thinner atmospheres, the impact of refraction on atmosphere detectability is even weaker. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, TRAPPIST-1

Strict Limits On Potential Secondary Atmospheres On The Temperate Rocky Exo-Earth TRAPPIST-1 d

by Keith CowingAugust 13, 2025August 13, 2025

The nearby TRAPPIST-1 system, with its seven small rocky planets orbiting a late-type M8 star, offers an unprecedented opportunity to search for secondary atmospheres on temperate terrestrial worlds.

a, NIRCam false-colour image, where each colour channel was constructed by stacking NIRCam filters as annotated. The placement of the NIRSpec micro-shutters is shown in white (nearly identical across the all visits). Dashed coloured circles indicate the 0.3 "-diameter apertures used to extract the CIRC2 photometry. The [O iii] 88 µm emission and the MIRI/F560W image are overlaid with red and green contours respectively, both drawn at 3σ-4σ-5σ. A red (green) hatched ellipse shows the ALMA restoring beam (F560W point spread function). A horizontal bar indicates a physical scale of 1 kpc at z = 11.122. b, SEDs of the main component (A) of JADES-GS-z11- 0, as observed by NIRCam, MIRI, and NIRSpec/PRISM (Section 2.1), as well as the faint neighbouring source (B) whose photometry (filter curves drawn at the bottom) is consistent with having the same redshift. The best-fit bagpipes models are shown as solid (component A) and dashed (B) coloured lines, with squares indicating the model photometry. c, Best-fit model SFHs of the two components, with shading representing 1σ uncertainty. The dotted black line and grey shading illustrates the rising SFH prior based on dark matter halo accretion (see text for details), scaled to the stellar mass of component A. -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Status Report

On The Origins Of Oxygen: ALMA And JWST Characterise The Multi-phase, Metal-enriched, Star-bursting Medium Within A ‘Normal’ z>11 Galaxy

by Keith CowingAugust 2, 2025August 2, 2025

The unexpectedly high abundance of galaxies at z>11 revealed by JWST has sparked a debate on the nature of early galaxies and the physical mechanisms regulating their formation.

Spatial distributions of MnS (left) and Na2S (right) clouds as a function of longitude, averaged over all latitudes, and pressure in our cloudy SPARC/MITgcm model. The color mapping represents the mass mixing ratio of the cloud particle, with the same scaling in each panel. -- astro-ph.EP

Astrogeology, Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

A Panchromatic Characterization Of The Evening And Morning Atmosphere Of WASP-107 b

by Keith CowingJuly 28, 2025July 28, 2025

Limb-resolved transmission spectroscopy has the potential to transform our understanding of exoplanetary atmospheres. By separately measuring the transmission spectra of the evening and morning limbs, these atmospheric regions can be […]