astro-ph.SR Archives

Comparison of synthetic and observed solar G-band intensity at wavelength 4306.8±15 Å at different positions across the solar disc (different rows). The synthetic G-band has been convolved with the SST photometric filter transmission function (Carlsson et al. 2004). The G-band observations were acquired with the Swedish 1-m Solar Telescope (SST, Scharmer et al. (2003a)) on La Palma in 2003-2004 (Berger et al. 2004; Lin et al. 2005, Van Der Voort priv. comm.). For more detailed information on these observations we refer the reader to https://www.isf.astro.su.se/data1/ gallery/. We show the disc center 𝜇 = 1 at the bottom and two angles approaching the limb 𝜇 = 0.92, 𝜇 = 0.55 above. The black and white levels of the observations were adjusted to account for the different processing of the individual measurements. --astro-ph.SR

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

Solar Carbon Abundance From 3D Non-LTE Modelling Of The Diagnostic Lines Of The CH Molecule

by Keith CowingNovember 20, 2025November 19, 2025

Context. The spectral lines of the CH molecule are a key carbon (C) abundance diagnostic in FGKM-type stars. These lines are detectable in metal-rich and, in contrast to atomic C […]

Primary (circles, ≤ 2 mas) and reserve (triangles, < 5 mas) candidate reference stars plotted in ecliptic coordinates in epoch J2027 and equinox 2027 with colors indicating rankings. The CVZs are shaded in cyan. Only one rank A star is in any of the CVZs, and the overall number of rank A reference star candidates is very low compared to other ranks. If only Rank A stars are viable reference star candidates, science target scheduling for the Roman Coronagraph will likely be restrictive. -- astro-ph.SR

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

CoronaGraph Instrument Reference stars for Exoplanets (CorGI-REx) I. Preliminary Vetting and Implications for the Roman Coronagraph and Habitable Worlds Observatory

by Keith CowingNovember 14, 2025November 14, 2025

The upcoming Roman Coronagraph will be the first high-contrast instrument in space capable of high-order wavefront sensing and control technologies, a critical technology demonstration for the proposed Habitable Worlds Observatory […]

The 13.6 − 17.7 µm range of the GM Aur spectrum. The continuum-subtracted JWST-MIRI data (black, top panel) is overlaid with the total modeled emission (red, top panel) from molecules (bottom panel) H2O (blue) and OH (pink). Slab model fits were also performed for HCN, C2H2, 12CO2, 13CO2, and 13C 12CH2, however, H2O and OH were the only positive detections, while the remaining species did not match our detection criteria (see Section 3.1). The detected bright H I, H2, and atomic emission lines are labeled with dashed lines. -- astro-ph.SR

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

JWST Reveals Carbon-rich Chemistry in a Transitional Disk

by Keith CowingNovember 14, 2025November 14, 2025

We present JWST-MIRI Medium Resolution Spectrometer (MRS) observations of the Classical T Tauri stars GM Aur and RX J1615.3-3255 (J1615), both hosting transitional disks.

The distribution of planets, main comet and asteroid belts around the Sun, and the equivalent analogues for Beta Pictoris and WD 1145+017. All distances are logarithmic, scaled such that they all have the same equilibrium temperature for a blackbody, meaning that the various sublimation lines are at the same x-axis locations for comparison. Distances from each star are labelled in stellar radii (upper scale) and astronomical units (lower scale). For the Sun, Solar system comets are shown with notable associated distances, belts and planets. For β Pictoris, the planets and main belts are noted. For the white dwarf WD 1145+017 the locations for the six transiting bodies are indicated, with a zoomed-in panel showing their labelled order from Vanderburg et al. (2015). -- astro-ph.EP

Astrochemistry, Astrogeology, Comets and Asteroids, Exoplanets, -moons, -comets, Icy Worlds, Imaging & Spectroscopy, Interstellar, Status Report

An Overview Of Exocomets

by Keith CowingNovember 13, 2025November 13, 2025

We give a general overview of what the scientific community refers to as “exocomets”.

Left panel: Multiple observations of proper motion of Sirius B from 1980 to 2022. From Earth, the separation between Sirius A and B varies between 3 and 11 arcsec on a period of 50.1 years. Sirius was first detected as an astrometric binary though is now considered a visual system (data observations kindly provided by Dr. Rachel Matson from USNO). Right panel: Sirius A and B characteristic wobble of astrometric binaries. -- astro-ph.SR

Astronomy & Telescopes, Exoplanets, -moons, -comets, Status Report, Stellar Cartography

Multiplicity Of Stellar Systems In The Solar Neighbourhood, Wide Binaries, And Planet-hosting Stars

by Keith CowingNovember 11, 2025November 11, 2025

This doctoral thesis studies stellar multiplicity in the solar neighborhood (d < 10 pc) and in systems hosting planets (d < 100 pc).

Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

Tidally Torn: Why the Most Common Stars May Lack Large, Habitable-Zone Moons

by Keith CowingNovember 9, 2025

Earth-like planets in the habitable zone (HZ) of M-dwarfs have recently been targeted in the search for exomoons.

The left panel shows a zoom of the GA and ethanol emission maps toward B0, B1 and B2 respectively, integrated over the velocity range [−10, 5] km s−1

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

Glycolaldehyde And Ethanol Toward The L1157 Outflow: Resolved Images And Constraints On Glycolaldehyde Formation

by Keith CowingOctober 24, 2025October 22, 2025

Two main formation routes have been proposed for interstellar complex organic molecules (iCOMs): on dust grain surfaces and in the gas phase. Observing such molecules in protostellar outflow shock regions […]

HST/WFC3 NICMOS F212N image of NGC 7027 with JWST MIRI-MRS FOVs for channels 1 (red), 2, and 3 (white) overlaid. The black cross indicates the position of the central star. The yellow contours outline the H2 gas morphology in the continuum-subtracted HST/NICMOS images from Latter et al. (2000). The small orange, pink, blue, and green boxes are the spaxels used to illustrate the AIB variability referred to hereinafter as the E ring, outer NE corner, inner region, and the SW ring, respectively. Credit: NASA/ESA, Latter et al. (2000). -- astro-ph.SR

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

PAH Spectral Diversity in NGC 7027 and the Evolution of Aromatic Carriers

by Keith CowingOctober 24, 2025October 22, 2025

Polycyclic Aromatic Hydrocarbons (PAHs) constitute a significant fraction of the Universe’s carbon budget, playing a key role in the cosmic carbon cycle and dominating the mid-infrared spectra of astrophysical environments […]

Mass-radius diagram for TOI-283 b (red star) and known transiting planets with mass determinations with a precision better than 30 % (parameters taken from the TEPCat database; Southworth 2011). Planets orbiting K-type stars (4000 ≤ Teff ≤ 5300 K) are marked with orange circles. The lines in the mass-radius diagram represent the composition models of Zeng et al. (2016, 2019) for planets with pure iron cores (100 % Fe, brown line), Earth-like rocky compositions (32.5 % Fe plus 67.5 % MgSiO3, dashed green line), Earth-like compositions with a 0.1% H2 envelope (dotted purple line), and a water world with a 0.1 % H2 gas envelope (dash-dotted blue line). We show some Solar System planets for reference (Venus, Earth, Uranus, and Neptune). -- astro-ph.EP

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

TOI-283 b: A Transiting Mini-Neptune In A 17.6-day Orbit Discovered With TESS And ESPRESSO

by Keith CowingOctober 23, 2025October 22, 2025

Super-Earths and mini-Neptunes are missing from our Solar System, yet they appear to be the most abundant planetary types in our Galaxy.

The 2-dimensional dust temperature distributions without viscous heating are shown for 10 L⊙ (top) and 100 L⊙ (bottom); Model E (left), Model E+D (middle), and Model PPD (right) are presented. The white solid line indicates the isothermal contour of Tdust = 100 K. The upper zoom-in panels of Model PPD show the water snowline inside the box of 20au×8au. -- astro-ph.SR

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Status Report

Water Snowline in Young Stellar Objects with Various Density Structures Using Radiative Transfer Models

by Keith CowingOctober 23, 2025October 22, 2025

Tracing the water snowline in low-mass young stellar objects (YSOs) is important because dust grain growth is promoted and the chemical composition varies at the water snowline, which influences planet […]

astro-ph.SR

Solar Carbon Abundance From 3D Non-LTE Modelling Of The Diagnostic Lines Of The CH Molecule

CoronaGraph Instrument Reference stars for Exoplanets (CorGI-REx) I. Preliminary Vetting and Implications for the Roman Coronagraph and Habitable Worlds Observatory

JWST Reveals Carbon-rich Chemistry in a Transitional Disk

An Overview Of Exocomets

Multiplicity Of Stellar Systems In The Solar Neighbourhood, Wide Binaries, And Planet-hosting Stars

Tidally Torn: Why the Most Common Stars May Lack Large, Habitable-Zone Moons

Glycolaldehyde And Ethanol Toward The L1157 Outflow: Resolved Images And Constraints On Glycolaldehyde Formation

PAH Spectral Diversity in NGC 7027 and the Evolution of Aromatic Carriers

TOI-283 b: A Transiting Mini-Neptune In A 17.6-day Orbit Discovered With TESS And ESPRESSO

Water Snowline in Young Stellar Objects with Various Density Structures Using Radiative Transfer Models

UKs Key Habitable Worlds Observatory Instrument In NASA’s Hunt For Earth-like Worlds

50 Years After Viking 1: The Mission That Changed The Search For Life On Mars

Offworld Science Training: From Lava Fields To Antarctica, Students Pave The Way For Artemis Moon Missions

Cliffs Of Ice On Mars

Brines Discovered In A Meteorite From A Primitive CM Asteroid