NIRSpec Archives

ChM diagram of M dwarfs in 47 Tucanae from JWS T-HS T photometry (grey dots). Spectroscopic targets observed with NIRSpec@JWS T are represented with filled coloured circles. Targets with no available mF322W2 from NIRCam@JWS T are plotted with ∆C F606W,F814W,F322W2=0.00 as empty circles. Different colors have been used for stars associated with different stellar populations on the ChM, specifically: first population (1P) stars are colored in red, second population ones have been colored in orange (2Pa), cyan (2Pb) and blue (2Pe). The [O/Fe] abundance vs. the ∆F606W,F814W and ∆C F606W,F814W,F322W2 values is shown in the upper and right panels, respectively. For each population, we plot the average values and the associated error. -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Imaging & Spectroscopy, Interstellar, Status Report

A JWST Project on 47 Tucanae. NIRSpec Spectroscopy of Multiple Populations Among M dwarfs

by Keith CowingJune 19, 2024June 19, 2024

We present the first spectroscopic estimates of the chemical abundance of M dwarf stars in a globular cluster (GC), namely 47 Tucanae. By exploiting NIRSpec on board the James Webb […]

This infographic compares the characteristics of three classes of stars in our galaxy: Sunlike stars are classified as G stars; stars less massive and cooler than our Sun are K dwarfs; and even fainter and cooler stars are the reddish M dwarfs. The size of the habitable zone is different for each class of star. In our solar system, the habitable zone begins just beyond the orbit of Venus and almost encompasses Mars. Credits: NASA, ESA and Z. Levy (STScI)

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

Reconnaissance Of Potentially Habitable Worlds With Webb Space Telescope

by Keith CowingJune 5, 2024June 5, 2024

Exoplanets are common in our galaxy, and some even orbit in the so-called habitable zone of their star. NASA’s James Webb Space Telescope has been busy observing a few of […]

The obtained NIRSpec Prism and G395H transmission spectra of WASP-39 b, shown as errorbars with green and blue centres, respectively. Also shown is a nominal model assuming 10× solar elemental abundances and Mie scattering aerosols, as discussed in section 7. The observations are binned to R∼100 for visual clarity, while the grey area denotes the persistent saturation region for NIRSpec Prism as shown in Figure 2 -- astro-ph.EP

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

Exoplanet Transit Spectroscopy with JWST NIRSpec: Diagnostics and Homogeneous Case Study of WASP-39 b

by Keith CowingMay 15, 2024September 18, 2025

The JWST has ushered in a new era of exoplanet transit spectroscopy. Among the JWST instruments, the Near-Infrared Spectrograph (NIRSpec) has the most extensive set of configurations for exoplanet time […]

Top, Upper Panels: Individual visit transmission spectra for ExoTiC-JEDI (left, purples) and Eureka! (right, greens). Lower Panel: Difference between individual visit transmission spectra for ExoTiC-JEDI (left) and Eureka! (right). On average, the ExoTiC-JEDI reductions for visit 1 and visit 2 are consistent to within 39 ppm, while the Eureka! reductions agree to within 48 ppm. The ExoTiC-JEDI and Eureka! reductions are consistent with each other to within the median transit depth uncertainty for both visit 1 and visit 2. Bottom, Upper Panel: Weighted average transmission spectrum from the two visits from the ExoTiC-JEDI (purple) and Eureka! (light green) reductions and joint fit transmission spectrum from the Eureka! reduction (dark green). Lower Panel: Difference between each of the combined ExoTiC-JEDI and Eureka! transmission spectra in ppm. As the difference between the two Eureka! methods is less the 5 ppm (black line), the two ExoTiC-JEDI– Eureka! lines are difficult to distinguish (coloured lines). On average, the combined visit Eureka! and ExoTiC-JEDI spectra are consistent to within 10 ppm. -- astro-ph.EP

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

JWST COMPASS: NIRSpec/G395H Transmission Observations of the Super-Earth TOI-836b

by Keith CowingApril 2, 2024April 2, 2024

We present two transit observations of the ~870K, 1.7RE super-Earth TOI-836b with JWST NIRSpec/G395H, resulting in a 2.8-5.2μm transmission spectrum. Using two different reduction pipelines, we obtain a median transit […]

Transmission spectrum of LHS 1140 b. The two transit observations are color coded, i.e., blue for the G235H grating and green for the G395H grating. The models shown are randomly selected solutions from the posterior distributions of Scenario 4 (Table 4, corresponding to N2-H2O atmospheres with deep clouds). We have applied the best-fit offsets to the data. The offset between the two visits is ∼ 50 ppm, while the offset between the two detectors within each of the two visits is negligible (see Figure 4 and Table 5). -- astro-ph.EP

Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, TRAPPIST-1, Water/Hycean Worlds & Oceanography

LHS 1140 b Is A Potentially Habitable Water World

by Keith CowingMarch 21, 2024March 21, 2024

LHS 1140 b is a small planet orbiting in the habitable zone of its M4.5V dwarf host. Recent mass and radius constraints have indicated that it has either a thick […]

Maps of the ring’s flux and brightness temperature as functions of ring radius and wavelength derived from the MIRI observations. The radial extent of the three main rings are shown at the far right of each plot (the Cassini Division is situated between the A and B rings). Note that the brightness temperature is more useful on the right-hand side of the figure, where thermal emission dominates over reflected sunlight. The brightness temperature rapidly increases at short wavelengths because of the increasing contribution of reflected sunlight. Narrow spectral features in the regions indicated by the shaded bands around 8 µm, 12 µm and 14µm are due to stray light from Saturn, but the bright line at 9.2 µm is due to the presence of highly crystalline water ice throughout the ring. -- astro-ph.EP

Gas Giants, Icy Worlds, Imaging & Spectroscopy, Press Release, Saturn

Water-Ice Dominated Spectra of Saturn’s Rings and Small Moons from JWST

by Keith CowingFebruary 27, 2024February 27, 2024

JWST measured the infrared spectra of Saturn’s rings and several of its small moons (Epimetheus, Pandora, Telesto and Pallene) as part of Guaranteed Time Observation program 1247.

JWST/NIRSpec integrated spectra and 1σ uncertainties (gray error bars) of Callisto’s leading (purple) and trailing (red) hemisphere, normalized to 1 at 3.82 μm and offset vertically for clarity. The G395H grating has a ~0.1 μm wide wavelength gap, shifting between ~4 and 4.2 μm across NIRSpec IFU’s 29 image slices. Some of the image slices that span Callisto’s disk include wavelength coverage between ~4 and 4.2 μm, which are shown here for Callisto’s leading (bright blue) and trailing (bright orange) hemispheres. All spectral features identified in this study are labeled, with dotted lines indicating their central wavelengths. Features with confirmed compositions have bolded labels, whereas weak features, or those with multiple compositional interpretations, are italicized and followed by question marks. Possible bands and spectral structure at wavelength >4.98 μm may result from data calibration artifacts and are not analyzed in this study. The inset box shows a close-up of the 4.19 to 4.42 μm wavelength range, highlighting the CO2 features we have identified and the different band centers for 12CO2 on Callisto’s leading (4.254 μm) and trailing (4.250 μm) hemisphere, as well as a feature near 4.3 μm that may result from an isotope of CO2 or could be a residual solar line (Appendix A.3). -- astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Callisto, Icy Worlds, Imaging & Spectroscopy, Jupiter, Status Report

Revealing Callisto’s Carbon-rich Surface And CO2 Atmosphere With JWST

by Keith CowingJanuary 31, 2024January 31, 2024

We analyzed spectral cubes of Callisto’s leading and trailing hemispheres, collected with the NIRSpec Integrated Field Unit (G395H) on the James Webb Space Telescope.

Sketch of typical dust grain chemical inventory. We suggest that OCN− , CH3CN and C2H5CN likely start to form in the cold dense core phase but are enhanced thermally during the warm-up stage where more volatile species have sublimated. -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Press Release

Hunt For Complex Cyanides In Protostellar Ices With JWST: Tentative Detection Of CH3CN And C2H5CN

by Keith CowingJanuary 18, 2024January 18, 2024

Nitrogen-bearing complex organic molecules have been commonly detected in the gas phase but not yet in interstellar ices. This has led to the long-standing question of whether these molecules form […]

An artistic representation of the “hot Saturn” exoplanet, HAT-P-18 b. CREDIT NASA/Eyes on Exoplanets - NASA

Astrogeology, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Press Release, TRAPPIST-1

Hot Saturn Exoplanet HAT-P-18 b And Its Parent Star

by Keith CowingJanuary 11, 2024January 10, 2024

Led by researchers from Université de Montréal’s Trottier Institute for Research on Exoplanets (iREx), a team of astronomers has harnessed the power of the revolutionary James Webb Space Webb Telescope […]

Best-fit model for the CO and H2O gas-phase rovibrational bands in II Zw 096-D1. The first panel shows the CO band, while the rest of the panels show the H2O one. The JWST/NIRSpec and MIRI-MRS rest-frame continuum-subtracted spectra and model fits correspond to the black histograms (filled in gray) and red lines, respectively. We show the model for the torus (brown dashed line), outflow (magenta dashed line), SF-extended (blue dashed line), and cold-extended (green dashed line) components. The vertical lines correspond to the main H recombination, H2, and fine structure lines. Black, red and orange ticks indicate the position of the 12CO ν=1-0, 13CO ν=1-0 and C18O ν=1-0 rovibrational lines. The blue ticks indicate the H2O ν2=1-0 rovibational lines that most contribute to the modelled spectrum. -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Imaging & Spectroscopy, Interstellar, Status Report

Structures Of Dust and gAs (SODA): Constraining The Innermost Dust Properties of II Zw96 With JWST Observations Of H2O And CO

by Keith CowingJanuary 9, 2024January 9, 2024

We analyze JWST NIRSpec+MIRI/MRS observations of the infrared (IR) gas-phase molecular bands of the most enshrouded source (D1) within the interacting system and luminous IR galaxy II Zw 096.

NIRSpec

A JWST Project on 47 Tucanae. NIRSpec Spectroscopy of Multiple Populations Among M dwarfs

Reconnaissance Of Potentially Habitable Worlds With Webb Space Telescope

Exoplanet Transit Spectroscopy with JWST NIRSpec: Diagnostics and Homogeneous Case Study of WASP-39 b

JWST COMPASS: NIRSpec/G395H Transmission Observations of the Super-Earth TOI-836b

LHS 1140 b Is A Potentially Habitable Water World

Water-Ice Dominated Spectra of Saturn’s Rings and Small Moons from JWST

Revealing Callisto’s Carbon-rich Surface And CO2 Atmosphere With JWST

Hunt For Complex Cyanides In Protostellar Ices With JWST: Tentative Detection Of CH3CN And C2H5CN

Hot Saturn Exoplanet HAT-P-18 b And Its Parent Star

Structures Of Dust and gAs (SODA): Constraining The Innermost Dust Properties of II Zw96 With JWST Observations Of H2O And CO

Why Europa’s Hidden Ocean May Be More Difficult To Reach Than Scientists Thought

Pinpointing Where Cells First Begin Copying DNA

Experimental Measurements of Benzene Ice Critical Saturation Ratios on Titan Tholins and Impact on the Microphysical Modeling of Titan’s South Polar Benzene Cloud

From Mars to Minas: Research Reclassifies Organisms That Thrive In Highly Saline Environments

Could Alien Signals Be Hiding On A Different Radio Channel?