Interstellar Archives

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 […]

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

First Identification and Chemical Modeling of New Thiol (−SH) Bearing Molecule in the Interstellar Medium: Dithioformic Acid

by Keith CowingNovember 13, 2024September 18, 2025

The study of complex organic molecules containing thiol (−SH) groups is essential in interstellar media because −SH plays an important role in the polymerization of amino acids (R-CH(NH2)-COOH).

Evolution of HNCS (top) and HSCN (bottom) fractional abundance as a function of time for an initial sulphur abundance (relative to nH) S+=1.5×10−6, a CR ionisation rate ξ=1.3×10−17 s−1, and a hydrogen number density , and a hydrogen number density nH=104, 105, 106, and 107cm−3

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

Evolution of Chemistry in the Envelope of HOt CorinoS (ECHOS) II. The puzzling Chemistry of Isomers as Revealed by the HNCS/HSCN Ratio

by Keith CowingNovember 13, 2024November 13, 2024

The observational detection of some metastable isomers in the interstellar medium with abundances comparable to those of the most stable isomer, or even when the stable isomer is not detected, […]

Graphical Abstract: γ-Ray is capable of driving an aqueous-phase CH4+H2O+O2 conversion selectively into CH3COOH via ⋅CH3 and ⋅OH radical intermediates, and driving an aqueous-phase CH3COOH+NH3 conversion into NH2CH2COOH via ⋅CH2COOH and ⋅NH2 radical intermediates. Such γ-ray driven aqueous-phase methane conversions probably play an important role in the formation network of complex organic molecules in the universe, and provides a strategy to convert abundant CH4 into value-added products at mild conditions. -- Angewandte Chemie International Edition

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

Interstellar Methane As Progenitor Of Amino Acids?

by Keith CowingNovember 7, 2024November 7, 2024

Gamma radiation can convert methane into a wide variety of products at room temperature, including hydrocarbons, oxygen-containing molecules, and amino acids, reports a research team in the journal Angewandte Chemie.

Interstellar, Missions & Hardware, Status Report

Communications Issues Resolved With Voyager 1 Interstellar Probe

by Keith CowingNovember 1, 2024November 1, 2024

On Oct. 24, NASA reconnected with the Voyager 1 spacecraft after a brief pause in communications. The spacecraft recently turned off one of its two radio transmitters, and the team […]

Comparison of 2D distribution of A(V), R(V), qPAH for dust clouds. For A(V) and R(V) maps, we select high-quality stars from Zhang & Green (2024), and remove lines of sight where only partial extinction is covered by XP. For qPAH map, we remove lines of sight where the qPAH map is of low quality (χ 2 /DOF > 3 or qPAH/σ(qPAH) < 3), or that cross multiple clouds (Equation 1). The binning method and selection of stars in the 2D maps are described in Appendix A. Despite different baselines and finer structures in different maps, all clouds tend to have lower R(V ) at high-qPAH regions, as indicated quantitatively on the per-star basis in Figure 5 -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Imaging & Spectroscopy, Interstellar, Mapping, Geodesy, Cartography, Bathymetry, Status Report, Stellar Cartography

Dust Extinction-curve Variation In The Translucent Interstellar Medium Is Driven By PAH Growth

by Keith CowingOctober 31, 2024October 31, 2024

The first all-sky, high-resolution, 3D map of the optical extinction curve of the Milky Way (Zhang & Green 2024) revealed an unexpected steepening of the extinction curve in the moderate-density, […]

JWST MIRI-MRS spectrum of DoAr 33. The insets show isolated emission features of some of the molecules detected, and the calculated continuum is shown as a pink line. Most of the unmarked emission lines correspond to water vapor. We discuss the presence of dust emission features in Appendix A. -- astro-ph.EP

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

JWST/MIRI Detection Of A Carbon-rich Chemistry In A Solar Nebula Analog

by Keith CowingOctober 26, 2024October 26, 2024

It has been proposed, and confirmed by multiple observations, that disks around low mass stars display a molecule-rich emission and carbon-rich disk chemistry as compared to their hotter, more massive […]

Potential energy contours for the C10H − − H2 system within the orientation-averaged 2D form discussed in the main text. It is obtained by the averaged combinations of the and angles following the procedure described in our earlier work (Mant et al. 2021). The H-end of the anion is represented by a blue dot along the x-axis. -- astro-ph.SR

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

Rotationally Inelastic Rate Coefficients For C7N− and C10H− anions in Collision With H2 at Interstellar Conditions

by Keith CowingOctober 25, 2024

The anions C7N− and C10H− are the two longest of the linear (C,N)-bearing and (C,H)-bearing chains which have so far been detected in the Interstellar Medium.

A representation of 1-cyanopyrene detected in space. Credit: NSF/NSF NRAO/AUI/S. Dagnello.

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

The Largest Molecule Ever Detected Using Radioastronomy

by Keith CowingOctober 25, 2024October 25, 2024

The discovery of a four-ring carbon molecule in a distant interstellar cloud may help to reveal how our own solar system formed.

CRIR map estimated from our parameter inference algorithm. All grayed out, hatched regions are estimated by our algorithm to have ζ > 5 × 10−−13 s −1 and one or more of the following issues. The ‘X’ hatching indicates regions where the estimated HCN or HNC abundance was below 10−12 with respect to hydrogen, and the dotted regions indicate locations where XHCN/XHNC > 4, with the two appearing together when both conditions are true. White and black numbers indicate the number of transitions that are detected with S/N > 3 for a given region, and purple outlines indicate when there are no transitions above the J = 2 − 1 that meet this threshold. Gray contours signify HCN 1 − 0 emission at 1, 3, and 5 Jy km s−1 beam−1 . Colored dots indicate the locations of recent star formation via radio continuum sources (supernova remnants and H II regions, Ulvestad & Antonucci 1997) and super hot cores (Rico-Villas et al. 2020). Note half of the unclassified sources are expected to be H II regions and half are thought to be supernova remnants. The green circle in the bottom right corner represents the ALCHEMI 1.′′6 (∼ 28 pc) beam. -- astro-ph.GA

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

Neural Network Constraints on the Cosmic-Ray Ionization Rate and Other Physical Conditions in NGC 253 with ALCHEMI Measurements of HCN and HNC

by Keith CowingOctober 25, 2024October 25, 2024

We use a neural network model and ALMA observations of HCN and HNC to constrain the physical conditions, most notably the cosmic-ray ionization rate (CRIR, zeta), in the Central Molecular […]

Interstellar

Chemical Pathways of SO2 With Hydrogen Atoms On Interstellar Ice Analogues

First Identification and Chemical Modeling of New Thiol (−SH) Bearing Molecule in the Interstellar Medium: Dithioformic Acid

Evolution of Chemistry in the Envelope of HOt CorinoS (ECHOS) II. The puzzling Chemistry of Isomers as Revealed by the HNCS/HSCN Ratio

Interstellar Methane As Progenitor Of Amino Acids?

Communications Issues Resolved With Voyager 1 Interstellar Probe

Dust Extinction-curve Variation In The Translucent Interstellar Medium Is Driven By PAH Growth

JWST/MIRI Detection Of A Carbon-rich Chemistry In A Solar Nebula Analog

Rotationally Inelastic Rate Coefficients For C7N− and C10H− anions in Collision With H2 at Interstellar Conditions

The Largest Molecule Ever Detected Using Radioastronomy

Neural Network Constraints on the Cosmic-Ray Ionization Rate and Other Physical Conditions in NGC 253 with ALCHEMI Measurements of HCN and HNC

Astrobiologist Dale Andersen’s Antarctic Field Report: 14 November 2026: Setting Up Lab and Dive Tents

Testing The Hypothesis, ‘Planetary Protection Is Expensive’ From The ESA Perspective

Tracing Galactic Dust Reddening with Polycyclic Aromatic Hydrocarbon Emission: SPHEREx Observations of the North Ecliptic Pole

Signatures of CH4 and NH3 in the Atmosphere of β Pictoris b

Hydrolyzed Hazes on Water-rich Exoplanets: Composition and Prebiotic Chemistry