[astro-ph.EP] We report observations of comet 81P/Wild 2, target of the Stardust sample return mission, on UT 2023 March 20 and 24 at a heliocentric distance (rH) of 1.85 au […]
NIRSpec
![Transmission spectra of TRAPPIST-1 c from the four JWST/NIRSpec PRISM epochs (4-pixel bins, 0.8–5.0 𝜇m), offset vertically by 200 ppm per epoch for clarity and colour-coded by date, with the inverse-variance-weighted mean spectrum (black, plotted at its true depth). Grey bands mark the stellar H2O features near 1.4 and 1.85 𝜇m. The dotted line marks 2.0 𝜇m, the boundary of the region where the contamination is strongest (Section 3). The 2023 November 8 visit contains a flare during transit and the 2024 July 9 visit shows activity outside transit (Section 2.5). -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Detecting.png?resize=1200%2C716&ssl=1)
Posted inAstronomy & Telescopes
Detecting Atmospheres In The Presence Of Stellar Contamination: An Empirically Calibrated Framework Applied To Four JWST/NIRSpec PRISM Transits Of TRAPPIST-1c
[astro-ph.EP] Transmission spectroscopy of rocky exoplanets orbiting late M dwarfs is limited by stellar contamination rather than photon noise.
![Rest-frame equivalent widths of C iii] 𝜆𝜆1907, 1909 (left) and C iv 𝜆𝜆1548, 1550 (right) against the direct 𝑇e-based ([O III]𝜆4363) metallicity. Curves are the star-forming photoionisation grids of Nakajima et al. (2018) at a burst age of 1 Myr and log(𝑛H/cm−3 ) = 3. Solid curves represent the POPSTAR single-star models (Mollá et al. 2009), and dashed curves indicate the BPASS binary models (Eldridge et al. 2017), coloured by ionisation parameter as shown in the colour-bar. -- [astro-ph.GA]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Precise.png?resize=1200%2C720&ssl=1)
Posted inAstrochemistry
Precise C-N-O Abundances of Individual Galaxies In The First Billion Years From Ultra-Deep, Rest-UV-to-Optical JWST Spectroscopy
[astro-ph.GA] We present ultra-deep JWST/NIRSpec 𝑅 ∼ 1000 spectroscopy of nine star-forming galaxies at 𝑧 = 6.0 − 8.3 in the GOODSN field, drawn from the Origins of Metal Enrichment […]
Posted inAtmospheres, Climate, Weather
Atmospheric Retrieval of Combined JWST, HST, and Ground-Based Observations Reveals a Featureless Transmission Spectrum for GJ 1132 b
[astro-ph.EP] We present a panchromatic transmission spectrum of GJ1132b spanning 0.71–5.16 μm, combining published transit observations from Magellan/LDSS3C, HST/WFC3 G141, and JWST/NIRSpec (G395H and G395M).
![The best-fit chemical equilibrium models to our co-added data performed with three different retrieval suites. For all chemical equilibrium fits, the models produced poor fits to several features on the spectrum, namely near 3 µm and between 4 − 5 µm region. For the 4.3 micron region, the differences between features are due to a combination of differences in the retrieval framework (namely prior constraints) and chemical networks used (FastChem vs GGChem) for each retrieval suite. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/GEMS-JWST.png?resize=1200%2C719&ssl=1)
Posted inExoplanets, -moons, -comets
GEMS JWST: HATS(-6 b): A Sub-solar Metallicity Giant Planet With Water, Methane And Ammonia In Its Atmosphere
[astro-ph.EP] HATS-6 b is one of several recently discovered Giant Exoplanets orbiting M-dwarf Stars (GEMS) and is part of a JWST survey that aims to compare bulk and atmospheric properties […]
Posted inExoplanets, -moons, -comets
JWST Transmission Spectroscopy Of TOI-3235 b: Challenges In Constraining Giant Planet Atmospheres Around M Dwarfs Amid Stellar Contamination
[astro-ph.EP] Giant planets orbiting low-mass M dwarfs challenge current planet formation theories, which predict that such planets are unlikely to form. Characterizing their atmospheres can provide key insight into their […]
![Vertical cut through the best-fit disk model on a logarithmic radial scale. Shown are temperatures, where the gas density, ϱdisk, exceeds an assumed ISM density of ϱISM = 2.7 × 10−24 g cm−3 (Ferrière 2001) by a factor of 1000. The snowline at Tsnow = 170 K and the 100 K-line, as well as the unity optical depth lines at a wavelength of 3.1 µm (computed for the best-fit model described in Sect. 5.2.2) measured from the star to the observer and from observer to the star, illustrate the temperature and dust density structure of the disk. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Spatial.png?resize=1200%2C715&ssl=1)
Posted inAstrochemistry
Spatial Distribution Of Water Ice In The Protoplanetary Silhouette Disk d216-0939
[astro-ph.EP] The composition of rocky planets depends on the dust in their natal protoplanetary disk (PPD), potentially containing water ice. Crystalline water ice was detected in the PPD d216-0939 in […]
Posted inIcy Worlds
Tracing The Source Of Carbon Oxides On The Large Moons Of Uranus
[astro-ph.EP] The Uranian moons Ariel, Umbriel, Titania, and Oberon are enriched in CO2 mixed with CO, but the origin(s) of these carbon oxides, be they primarily native or radiolytic, remains […]
Posted inBeta Pictoris
Discovery Of An Exterior Third Planet Orbiting β Pictoris
[astro-ph.EP] We report the discovery of β Pictoris d (β Pic d), a third giant planet in the β Pictoris system, which now becomes only the second directly imaged system […]
Posted inExoplanets, -moons, -comets
C,N,O,S, And Photochemistry In A Temperate Giant Planet Orbiting A Late M Dwarf
[astro-ph.EP] We report the JWST NIRSpec/PRISM transit spectrum of TOI-6894b, an exceptional 420 K sub-Saturn that is the only known giant planet transiting a late M dwarf. Remarkably, both the […]