interstellar medium Archives

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

On the Abiotic Origin of Dimethyl Sulfide: Discovery of DMS in the Interstellar Medium

by Keith CowingFebruary 10, 2025February 10, 2025

Following the discovery of dimethyl sulfide (CH3SCH3, DMS) signatures in comet 67P/Churyumov-Gerasimenko, we report the first detection of this organosulfur species in the interstellar medium, during the exploration of an […]

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

Rotational Excitation of Vinyl Cyanide by Collisions with Helium Atoms at Low Temperature

by Keith CowingFebruary 4, 2025February 4, 2025

Among the numerous molecular systems found in the interstellar medium (ISM), vinyl cyanide is the first identified olephinic nitrile. While it has been observed in various sources, its detection in […]

Evidence for the formation of two-center one-electron (2c–1e) bonds in the predissociation complexes of the radical cations in ethanolamine (A), propanol (B), butanenitrile (C), and glycolamide (D). The ELF basins are shown in the left column, the projections into the heavy atom planes are shown in the second column, the spin densities for the unpaired electrons are shown in the third column, and the 2c–1e AdNDP orbitals are shown in the right column. -- Chemical Science

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

What Drives The Formation Of Unsaturated Molecules In The Interstellar Medium?

by Keith CowingJanuary 20, 2025January 19, 2025

We present a computational investigation into the fragmentation pathways of ethanolamine (C2H7NO, EtA), propanol (C3H8O, PrO), butanenitrile (C4H7N, BuN), and glycolamide (C2H5NO2, GlA)—saturated organic molecules detected in the interstellar medium […]

(a) Cross sections of four different PAHs in the UV region (0.2-0.4 µm). On average, Naphthalene, Anthracene, and Pyrene have stronger cross-sections among all 4 considered. (b) Collective cross sections of PAHs and other molecules on Earth (taken from Kopparapu et al. (2021)) for the wavelength coverage of a nominal 8m class Habitable Worlds Observatory (0.2-2 µm). PAHs have stronger features than other molecules in this region. The region between 0.3-0.4 µm serves as a promising window to detect PAHs due to the least overlap with other molecular cross-sections. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Habitable Zones, Imaging & Spectroscopy, SETI & Technosignatures, Status Report

Polycyclic Aromatic Hydrocarbons (PAHs) As An Extraterrestrial Atmospheric Technosignature

by Keith CowingJanuary 14, 2025January 14, 2025

Polycyclic Aromatic Hydrocarbons are prevalent in the universe and interstellar medium but are primarily attributed to anthropogenic sources on Earth, such as fossil fuel combustion and firewood burning.

Metallicity calculated over the full lines of sight as a function of distance from the Galactic center plotted for this work compared with literature results. The red diamonds are the results from the fit to abundance patterns for all metals, the green and purple diamonds are fits to the refractory and volatile metals respectively. We do not include the fits for ρ Oph A because of the limited data. The fit to the refractory metals for θ 1 Ori C is 1.7, which we do not consider as physical, so it is excluded in this plot. -- astro-ph.GA

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

Investigating Chemical Variations Between Interstellar Gas Clouds In The Solar Neighbourhood

by Keith CowingJanuary 13, 2025January 12, 2025

The interstellar medium (ISM) is a fundamental component of the Milky Way. Studying its chemical composition and the level of its chemical diversity gives us insight into the evolution of […]

Energy diagram for the C2H5 + S reaction. Values in square brackets indicate energies for the same well in the C2H5 + O reaction studied in Vazart et al. (2020). Insets correspond to the structures at the potential wells. We note that the products cy-CH2SCH2 + H and C2H3SH + H are almost isoenergetic. -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Intelligence & Language, Interstellar, Status Report

Detection of Thioacetaldehyde (CH3CHS) in TMC-1: Sulfur-oxygen Differentiation Along The Hydrogenation Sequence

by Keith CowingJanuary 11, 2025January 11, 2025

In recent years the chemistry of sulfur in the interstellar medium has experienced a renewed interest due to the detection of a large variety of molecules containing sulfur.

Integrated intensity map of the Class I CH3OH maser at 36 GHz obtained with the Yebes 40m telescope toward the Sgr B2 molecular cloud. Black cross indicates the location of G+0.693, where we have conducted our deep spectroscopic surveys with the IRAM 30m and Yebes 40m telescopes. Symbols show the location of the Sgr B2(N), (M) and DS massive star-forming regions. -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Interstellar, Status Report

Chemistry In The Galactic Center

by Keith CowingJanuary 8, 2025January 8, 2025

Gas and dust in the Galactic Center are subjected to energetic processing by intense UV radiation fields, widespread shocks, enhanced rates of cosmic-rays and X-rays, and strong magnetic fields.

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Icy Worlds, Interstellar, Pluto, Status Report, Triton

Clouds and Hazes in the Atmospheres of Triton and Pluto

by Keith CowingNovember 20, 2024November 20, 2024

Clouds and hazes are abundant in the thin and cold atmospheres of Triton and Pluto, where they are thought to be produced by interactions between atmospheric gases and ultraviolet photons […]

Results for the offset retrieval runs. Top panel: Best-fitting spectra for the Cloudless and PAH models (HST STIS + ELT + TESS data in black, G141 and Spitzer data including the best-fitting offsets for both retrievals in blue and green, respectively). Bottom panel: Residuals are plotted for each model in the respective colors showing the deviation of the data points from the spectra in units of the corresponding transit depth error (𝜎). The shaded bars indicate the 1, 3 and 5 𝜎 regions. Finally, the subpanel presents the model quality, showcasing the evidences as absolute deviations (Δln𝑍) from the lower model (for details refer to Table A1) and the reduced 𝜒2 -- astro-ph.EP

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

Detectability of Polycyclic Aromatic Hydrocarbons in the Atmosphere of WASP-6 b with JWST NIRSpec PRISM

by Keith CowingNovember 16, 2024November 16, 2024

Polycyclic Aromatic Hydrocarbons (PAHs) have been detected throughout the universe where they play essential roles in the evolution of their environments.

Calculated reaction pathways with relative energies expressed in eV. Cartesian coordinates of the optimized structures are in the Supporting Information (Table A1). -- astro-ph.GA

Astrochemistry, Astrogeology, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Icy Worlds, Imaging & Spectroscopy, Interstellar, Status Report

Chemical Pathways of SO2 With Hydrogen Atoms On Interstellar Ice Analogues

by Keith CowingNovember 15, 2024November 15, 2024

Sulfur dioxide (SO2) is a sulfur-containing molecule expected to exist as a solid in the interstellar medium (ISM). In this study, we performed laboratory experiments and computational analyses on the […]

interstellar medium

On the Abiotic Origin of Dimethyl Sulfide: Discovery of DMS in the Interstellar Medium

Rotational Excitation of Vinyl Cyanide by Collisions with Helium Atoms at Low Temperature

What Drives The Formation Of Unsaturated Molecules In The Interstellar Medium?

Polycyclic Aromatic Hydrocarbons (PAHs) As An Extraterrestrial Atmospheric Technosignature

Investigating Chemical Variations Between Interstellar Gas Clouds In The Solar Neighbourhood

Detection of Thioacetaldehyde (CH3CHS) in TMC-1: Sulfur-oxygen Differentiation Along The Hydrogenation Sequence

Chemistry In The Galactic Center

Detectability of Polycyclic Aromatic Hydrocarbons in the Atmosphere of WASP-6 b with JWST NIRSpec PRISM

Chemical Pathways of SO2 With Hydrogen Atoms On Interstellar Ice Analogues

NASA Establishes Mars Forward Operational Risk and Contamination Evaluation (M-FORCE) Tiger Team to Shape Mars Planetary Protection Protocols

Opportunity to Contribute to NASA DARES Community White Paper on Phototrophic Biosignatures

The Search For Life Elsewhere: Avoiding Hype and Fostering Public Understanding

Panchromatic Spectra of Nearby Low-mass and Sun-like Stars with Directly Imageable Habitable Zones

Alfred: A Flexible, User-Friendly Python Package for Exoplanet Confirmation