NIRSpec Archives

Contributions of molecules in the JWST MIRI range for the transmission spectrum of K2-18 b, assuming 1% CO2 and CH4, and 10−5 by volume for each of DMS, diethyl sulfide, methacrylonitrile, trans-2-pentene, 2-butene and propyne. -- astro-ph.EP

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

A Systematic Search for Trace Molecules in Exoplanet K2-18 b

by Keith CowingMay 16, 2025May 16, 2025

The first transmission spectrum of the habitable-zone sub-Neptune K2-18 b with JWST has opened a new avenue for atmospheric characterisation of temperate low-mass exoplanets.

Astrochemistry, Astrogeology, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Hot sub-Neptune Exoplanet TOI-421 b NIRISS/NIRSpec Transmission Spectrum

by Keith CowingMay 6, 2025

This is a transmission spectrum captured by the NASA/ESA/CSA James Webb Space Telescope that reveals the presence of water (H2O) and the possible presence of sulfur dioxide (SO2) and carbon […]

Breakdown of our best-fit model for the transit spectrum of TOI-270 d. Absorption bands of CH4, CO2 are clearly visible and one isolated absorption band of CS2 contributes at 4.6 µm. The impact of water, CO and SO2 on the spectrum is negligible. The model has been smoothed for visual clarity. astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography

Evidence For Sulfur Chemistry In The Atmosphere Of The Warm Sub-Neptune TOI-270 d

by Keith CowingApril 18, 2025April 18, 2025

Context: Recent JWST measurements allow access to the near-infrared spectrum of the sub-Neptune TOI-270 d, for which two different interpretations, a high-metallicity miscible envelope and a lower metallicity hycean world, […]

Spectral maps illustrating the distribution in the band centers, depths, and areas for (top) Europa’s 1.5 µm band (1.48 – 1.74 µm) -- astro-ph.EP

Analog Studies, Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Caves, Craters, Mountains, Subsurface, Lava Tubes, Cryobiology, Europa, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Jupiter, Mapping, Geodesy, Cartography, Bathymetry, Status Report, Water/Hycean Worlds & Oceanography

JWST Reveals Spectral Tracers of Recent Surface Modification on Europa

by Keith CowingApril 8, 2025April 8, 2025

Europa has been modified by a variety of geologic processes, exposing internally-derived materials that are heavily irradiated by charged particles trapped in Jupiter’s magnetosphere.

At the left, an enhanced-color image of Neptune from NASA’s Hubble Space Telescope. At the right, that image is combined with data from NASA’s James Webb Space Telescope. The cyan splotches, which represent auroral activity, and white clouds, are data from Webb’s Near-Infrared Spectrograph (NIRSpec), overlayed on top of the full image of the planet from Hubble’s Wide Field Camera 3. - STSCI

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Ice Giant, Icy Worlds, Imaging & Spectroscopy, Neptune, People Of Astrobiology, Press Release, Radiation, Space Weather & Heliophysics

Webb Space Telescope Captures Neptune’s Auroras For First Time

by Keith CowingApril 4, 2025May 12, 2025

For the first time, NASA’s James Webb Space Telescope has captured bright auroral activity on Neptune. Auroras occur when energetic particles, often originating from the Sun, become trapped in a […]

This artist’s concept shows what the isolated planetary-mass object SIMP 0136 could look like based on recent observations from NASA’s James Webb Space Telescope and previous observations from Hubble, Spitzer, and numerous ground-based telescopes. Researchers used Webb’s NIRSpec (Near-Infrared Spectrograph) and MIRI (Mid-Infrared Instrument) to measure subtle changes in the brightness of infrared light as the object completed two 2.4-hour rotations. -- NASA, ESA, CSA, and Joseph Olmsted (STScI)

Astronomy & Telescopes, Atmospheres, Climate, Weather, Brown Dwarfs, Exoplanets, -moons, -comets, Gas Giants, Icy Worlds, Imaging & Spectroscopy, Press Release

Webb Exposes Complex Atmosphere of Free-Floating Super-Jupiter SIMP 0136

by Keith CowingMarch 4, 2025March 4, 2025

An international team of researchers has discovered that previously observed variations in brightness of a free-floating planetary-mass object known as SIMP 0136 must be the result of a complex combination […]

Images of the trans-Neptunian objects (TNOs) Pluto [left] and Arrokoth [right], the primary flyby targets of NASA’s New Horizons spacecraft in 2015 and 2019. NASA’s James Webb Space Telescope is capable of obtaining observations for in-depth studies of a wide range of TNOs that both complement, and go beyond what was learned by New Horizons. (Image credits: NASA/SwRI/JHU-APL)

Astrochemistry, Astrogeology, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Comets and Asteroids, Cryobiology, Icy Worlds, Imaging & Spectroscopy, Pluto, Status Report

Webb Reveals The Ancient Surfaces of Trans-Neptunian Objects

by Keith CowingFebruary 13, 2025February 13, 2025

Trans-Neptunian objects (TNOs) are icy bodies ranging in size from Pluto and Eris (dwarf planets with diameters of about 1,500 miles) down to tens of miles (Arrokoth) and even smaller. […]

A simplified diagram of the KPIC phase II instrument including the FIU and FEU. All moving mechanisms are denoted with double ended arrows. The options for each mechanism are listed next to them. The options highlighted in orange are the default settings used for nominal K band science operations most similar to the original phase I mode. The green options are alternative settings available for the many phase II modes. -- astro-ph.IM

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

Technical Description and Performance of the Phase II Version of the Keck Planet Imager and Characterizer

by Keith CowingFebruary 6, 2025February 6, 2025

The Keck Planet Imager and Characterizer (KPIC) is a series of upgrades for the Keck II Adaptive Optics (AO) system and the NIRSPEC spectrograph to enable diffraction limited, high resolution […]

Irregular satellite orbital inclinations and semimajor axes (normalized to Jupiter’s Hill radius). Family groupings are given as indicated. The prograde population is dominated in mass and number by the Himalia family. The retrograde population is categorized into three orbital families, with the more widely dispersed Pasiphae and Ananke families and the more tightly grouped Carme family. This work studies the Himalia, Carme, Pasiphae, and Ananke families, as well as the isolated satellite Themisto. Orbital parameters from JPL Horizons. -- astro-ph.EP

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Jupiter, Meteorites & Asteroids, Status Report

JWST Reveals Varied Origins Between Jupiter’s Irregular Satellites

by Keith CowingFebruary 5, 2025February 5, 2025

We report observations of eight Jovian irregular satellites with JWST’s NIRSpec instrument: Himalia, Elara, Pasiphae, Sinope, Lysithea, Carme, Ananke, and Themisto. Irregular satellite families, which are presumed to have formed […]

Best fits for the cloud extinction models once their retrievals are finished. Observational data are shown as black/grey dots with error bars. -- astro-ph.EP

Astrochemistry, Astrogeology, Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

The Role of Cloud Particle Properties on WASP-39b Transmission Spectrum Based on JWST/NIRSpec Observations

by Keith CowingFebruary 3, 2025February 2, 2025

Aerosols are capable of having a huge influence on reflected, emitted and transmitted planetary spectra. The Near InfraRed Spectrograph (NIRSpec) using the PRISM mode on board of the James Webb […]