Interstellar Archives

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

Molecules That Store Carbon Discovered In A Distant Interstellar Cloud

by Keith CowingOctober 24, 2024

The discovery of pyrene derivatives in a distant interstellar cloud may help to reveal how our own solar system formed.

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

Infrared Spectra of Solid-State Ethanolamine: Laboratory Data in Support of JWST Observations

by Keith CowingOctober 17, 2024October 17, 2024

Ethanolamine (NH2CH2CH2OH, EA) has been identified in the gas phase of the ISM within molecular clouds. Although EA has not been directly observed in the molecular ice phase, a solid […]

Overview of our models for gas disk and particles evolution in different disk regions. The blue and yellow particles represent silicates with and without refractory carbon. The light blue particles represent icy pebbles. The pink particles show the oxygen atoms which are formed by the destruction of oxygen molecules because of the FUV radiation which is described as red arrows. The light blue dashed line is the snow line. Icy pebbles enclosing many small silicates drift to the snow line (blue dashed line) from the outer region. Orange upper and lower layers are FUV-exposed regions, where oxygen atoms exist. -- astro-ph.EP

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Habitable Zones, Imaging & Spectroscopy, Interstellar, Status Report

Effect of Different Stickiness Between Icy and Silicate Particles on Carbon Depletion in Protoplanetary Disks

by Keith CowingOctober 12, 2024October 12, 2024

Earth and other rocky bodies in the inner Solar System are significantly depleted in carbon compared to the Sun and interstellar medium (ISM) dust.

IR difference spectra obtained upon 2 keV electron irradiation of a 13C 18O:CS2 ice sample at 7 K (Exp. 7). IR band assignments are indicated for the initial ice components (black), and ice chemistry products (blue), including the OCS isotopologs (red). -- astro-ph.GA

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

Ice Origins of OCS and Chemistry of CS2-bearing Ice Mantles

by Keith CowingOctober 11, 2024

Understanding the formation of carbonyl sulfide (OCS) in interstellar ices is key to constrain the sulfur chemistry in the interstellar medium (ISM), since it is the only ice S-bearing molecule […]

CO and PAH emission in one nearby galaxy. The left panel shows an inclination-corrected ALMA CO(2-1) image of NGC 2903 with contours at 1.25, 3.1, 31, and 100 K km s−1 . The right panel shows a predicted CO(2-1) intensity map based on JWST F770WPAH and the prescription in Eq. 5. The contours are the same as on the left panel, and they show a very close correspondence between CO and PAH emission. At the same time, CO(2-1) emission is underestimated in the bar ends, highlighting improvements to be explored in future work. This figure also shows the improved sensitivity of JWST compared to ALMA at recovering faint emission, with the 5σ RMS noise indicated on each colorbar. -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Interstellar, Status Report

Polycyclic Aromatic Hydrocarbon and CO(2-1) Emission at 50-150 pc Scales in 66 Nearby Galaxies

by Keith CowingOctober 10, 2024October 10, 2024

Combining Atacama Large Millimeter/sub-millimeter Array CO(2-1) mapping and JWST near- and mid-infrared imaging, we characterize the relationship between CO(2-1) and polycyclic aromatic hydrocarbon (PAH) emission at ~100 pc resolution in […]

Two-dimensional fits of U, qPAH, and Σd as a function of a combination of the resolved stellar mass and star formation rate. Top row: 2D histograms of the Σ⋆–ΣSFR plane, where the bin values show the average U (left column), qPAH (center column), and Σd (right column). The light bins are calculated for all pixels passing the 3σ S/N cut, and the bright bins are calculated for pixels passing that same cut and that that have Σ⋆ and ΣSFR above the completeness thresholds. The 2D fit uses the standard deviations within each bin as errors in the linear regression. Bottom row: The x-axis shows the best-fit using both Σ⋆ and ΣSFR. The y-axis shows the observed data. The best-fit coefficients are reported in Table 5. -- astro-ph.GA

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

The Resolved Behavior of Dust Mass, Polycyclic Aromatic Hydrocarbon Fraction, and Radiation Field in ~ 800 Nearby Galaxies

by Keith CowingOctober 8, 2024October 8, 2024

We present resolved 3.6−250 μm dust spectral energy distribution (SED) fitting for ∼800 nearby galaxies. We measure the distribution of radiation field intensities heating the dust, the dust mass surface […]

Abundances of the ammonium cation w.r.t. H2O ice plotted against the τintC4/τintC3 ratios of ices toward isolated dense clouds (left, blue) and protostars (right, red). To facilitate comparison, the protostellar and cloud values are also plotted in the left and right plots, respectively, in light gray. A higher τintC4/τintC3 is indicative of a greater redshift in the peak position of the 6.85 μm feature. The plotted values are taken from Boogert et al. (2011) (clouds) and Boogert et al. (2008) (protostars). The Spearman’s rank correlation coefficient ρ and the p-value indicating probability of non-correlation are provided in the top right corner. The plotted NH4 + abundances have been multiplied by a correction factor of 4.4/3.6 to account for the difference between NH4+ ν4 mode band strength used by Boogert et al. (2008) and Boogert et al. (2011) (4.4×10-17 cm molec–1 from Schutte & Khanna 2003) and the band strengths calculated in this work to enable a direct comparison to our NH4+ ice upper limits in Table 5. Upper limits have been excluded from this plot, as well as data from the sources 2MASS J19214480+1121203 (due to the high error of its τintC4/τintC3 ratio) and IRAS 03301+3111 (due to its τintC4/τintC3 ratio being undefined because its τintC3 = 0). -- astro-ph.GA

Astrochemistry, Biochemistry & Organic Chemistry, Interstellar, Status Report

Ammonium hydrosulfide (NH4SH): A Potential Significant Sulfur Sink In Interstellar Ices

by Keith CowingOctober 7, 2024October 7, 2024

Sulfur is depleted with respect to its cosmic standard abundance in dense star-forming regions. It has been suggested that this depletion is caused by the freeze-out of sulfur on interstellar […]

GOTHAM spectra showcasing several 1-cyanopyrene lines detected in TMC-1 observations. The original GOTHAM observational data for which one channel corresponds to 1.4 kHz were smoothed with a Hanning window to a resolution of 14 kHz, depicted in black. The spectrum of 1-cyanopyrene is overplotted in violet using source-dependent molecular parameters as reported in Table S4. The quantum numbers of each transition, ignoring 14N nuclear electric quadrupole splitting, are reported. Each line contains multiple closely spaced K-components of each transition which are denoted α, β, γ, δ = {0,1}, {1,2}, {2,3}, {3,4}. -- astro-ph.GA

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Comets and Asteroids, Imaging & Spectroscopy, Interstellar, Sample Return, Status Report

Discovery Of Interstellar 1-cyanopyrene: A Four-ring Polycyclic Aromatic Hydrocarbon In TMC-1

by Keith CowingOctober 5, 2024October 7, 2024

Polycyclic aromatic hydrocarbons (PAHs) are thought to be the most abundant class of molecules in space, yet their interstellar lifecycle is poorly understood due to difficulties detecting individual PAHs.

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

Proposed Importance Of HOCO Chemistry: Inefficient Formation Of CO2 From CO And OH Reactions On Ice Dust

by Keith CowingOctober 3, 2024October 3, 2024

With the advent of JWST ice observations, dedicated studies on the formation reactions of detected molecules are becoming increasingly important. One of the most interesting molecules in interstellar ice is […]

Jimmy Carter's Interstellar message - Astrobiology.com

Astrobiology (general), Interstellar, SETI & Technosignatures

Centenarian Jimmy Carter’s Interstellar Message

by Keith CowingOctober 2, 2024October 2, 2024

Editor’s note: Happy 100th birthday President Jimmy Carter. Many younger people are unaware of the fact that you wrote a letter that is on board both Voyager spacecraft now traversing […]

Interstellar

Molecules That Store Carbon Discovered In A Distant Interstellar Cloud

Infrared Spectra of Solid-State Ethanolamine: Laboratory Data in Support of JWST Observations

Effect of Different Stickiness Between Icy and Silicate Particles on Carbon Depletion in Protoplanetary Disks

Ice Origins of OCS and Chemistry of CS2-bearing Ice Mantles

Polycyclic Aromatic Hydrocarbon and CO(2-1) Emission at 50-150 pc Scales in 66 Nearby Galaxies

The Resolved Behavior of Dust Mass, Polycyclic Aromatic Hydrocarbon Fraction, and Radiation Field in ~ 800 Nearby Galaxies

Ammonium hydrosulfide (NH4SH): A Potential Significant Sulfur Sink In Interstellar Ices

Discovery Of Interstellar 1-cyanopyrene: A Four-ring Polycyclic Aromatic Hydrocarbon In TMC-1

Proposed Importance Of HOCO Chemistry: Inefficient Formation Of CO2 From CO And OH Reactions On Ice Dust

Centenarian Jimmy Carter’s Interstellar Message

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