astro-ph.SR Archives

Intensity maps at 4.4 µm with the apertures chosen for the fit. Aperture centers and diameters are listed in Table C.1. -- astro-ph.GA

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

Identification Of Solid N2O In Interstellar Ices Using Open JWST Data

by Keith CowingJanuary 16, 2026January 16, 2026

Context. There are only six molecules containing N-O bond that are detected in gaseous phase in interstellar medium. One of those is nitrous oxide (N2O), which was searched for but […]

Color-magnitude diagram showing the targets in the ExEP target list for HWO. The grey points represent a sample of stars within 100 pc taken from Gaia DR3. The cyan points indicate the locations of the Mamajek & Stapelfeldt (2024) targets that are in Gaia and have not been observed with speckle imaging. Orange squares highlight 80 ExEP list targets that have ‘Alopeke, Zorro, or NESSI observations. Red stars show the 27 targets that have been identified as members of stellar multiples by this work. The top axis provides approximate G − GRP values for F0V, G0V, K0V, and M0V stars. -- astro-ph.SR

Astronomy & Telescopes, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, Stellar Cartography

Paving the Road to the Habitable Worlds Observatory with High-Resolution Imaging I: New and Archival Speckle Observations of Potential HWO Target Stars

by Keith CowingJanuary 12, 2026

One of the key goals of the Habitable Worlds Observatory (HWO) is to directly image about 25 potentially habitable exoplanets and determine their properties.

Illustration of flare heating in three types of stars. The dashed line marks the stellar surface; blue areas show the quiet atmosphere, and red areas show regions heated during a white-light flare. Vertical arrows indicate the radiative output, with length proportional to intensity. In solar-like stars (left), heating is regulated by hydrogen ionization, which limits temperatures of white-light flares to ∼ 9000 K. In late M dwarfs like TRAPPIST-1 (middle), molecular hydrogen dissociation acts as a thermostat, capping temperatures of white-light flares near ∼ 3500 − 4000 K. In early M dwarfs (right), insufficient concentration of H2 means the dissociation thermostat is ineffective, allowing higher white-light flare temperatures. -- astro-ph.SR

Exoplanets, -moons, -comets, Radiation, Space Weather & Heliophysics, Status Report, TRAPPIST-1

Molecular Hydrogen Controls The Temperatures Of Flares On TRAPPIST-1

by Keith CowingJanuary 6, 2026January 6, 2026

Early JWST observations of TRAPPIST-1 have revealed an unexpected puzzle: energetic white-light flares (E>1030 erg) reach temperatures of only ∼3500–4000,K, nearly three times cooler than typical solar flares, which peak […]

Surface flux density observed and modelled. The m2F12-37-2.5 (dark green) and cF13-500-3 (light green) stellar atmosphere models are plotted at coefficients Xˆ 1=1 and Xˆ 2 = 1 (the theoretical assumption of the entire stellar surface exhibiting flaring activity). For AU Mic during a flare, the red solid and orange dashed lines show the fitted model spectrum at flare maximum using coefficients from the example fit (the flare data are stated in Table A.1 in Appendix A.2). The inverse H6 model at flare maximum, pre-flare and the ‘fiducial flare’ model from Loyd et al. (2018a) with a comparable ED is plotted as blue dash-dotted, light blue dashed, and purple dashed lines, respectively. Blackbody curves for 3850 K, 6000 K, 8000 K, and 10,000 K are included in black solid, dotted, dash-dotted and dashed lines. The panchromatic AU Mic flux from Feinstein et al. (2022) is plotted in light grey. Insets highlight the FUV (lower left) and TESS (lower right) wavelength ranges. -- astro-ph.SR

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Press Release, Radiation, Space Weather & Heliophysics

Young M Dwarfs Flare Activity Model: Towards Better Exoplanetary Atmospheric Characterisation

by Keith CowingDecember 8, 2025December 8, 2025

Context. Stellar flares can significantly influence the atmospheres and habitability of orbiting exoplanets, especially around young and active M dwarfs. Understanding the temporally and spectrally resolved activity of such stars […]

Analytical predictions for the astrometric effect of a moon with varying mass and distance to HD 206893 B. GRAVITY could in principle detect moons lower than a Neptune mass at larger periods. The fit of the GRAVITY data is shown as a green point assuming the mass and period as upper limits in our tentative detection. The orange area shows the plausible parameter space where a moon could be located, and still be potentially detectable with GRAVITY assuming an astrometric accuracy of 10 µas (see section 3.3). -- astro-ph.EP

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

Exomoon Search With VLTI/GRAVITY Around The Substellar Companion HD 206893 B

by Keith CowingNovember 26, 2025June 10, 2026

Direct astrometric detection of exomoons remains unexplored. This study presents the first application of high-precision astrometry to search for exomoons around substellar companions.

The recovery probability (successful AltaiPony detection) of injected flares in the TESS light curves of GJ 1132 (top left), TOI-2445 (top right), TRAPPIST-1 (bottom left) and the average of recovered flare durations (in minutes) and flare SNR for all three stars (bottom right). From tests on approximately 6500 injected flares per star, these heatmaps show the probability that AltaiPony detects a flare of a given duration and amplitude relative to the light curve noise. The color of each bin represents the recovery probability from 0 to 1, with black contours indicating the approximate curves of of 25%, 50%, 75% and 90% recovery probability. Although the noise levels within each stars’ light curve varies greatly, we see consistent recovery probability of flares. -- astro-ph.SR

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Space Weather & Heliophysics, Status Report, Stellar Cartography

Stellar Flares In The TESS Light Curves Of Planet-hosting M dwarfs

by Keith CowingNovember 20, 2025November 20, 2025

M dwarfs are magnetically active stars that frequently produce flares, which have implications for both stellar evolution and exoplanet studies.

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”.

astro-ph.SR

Identification Of Solid N2O In Interstellar Ices Using Open JWST Data

Paving the Road to the Habitable Worlds Observatory with High-Resolution Imaging I: New and Archival Speckle Observations of Potential HWO Target Stars

Molecular Hydrogen Controls The Temperatures Of Flares On TRAPPIST-1

Young M Dwarfs Flare Activity Model: Towards Better Exoplanetary Atmospheric Characterisation

Exomoon Search With VLTI/GRAVITY Around The Substellar Companion HD 206893 B

Stellar Flares In The TESS Light Curves Of Planet-hosting M dwarfs

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

Astrobiologist Dale Andersen’s Antarctic Field Report: 9 November 2026: Lake Untersee Basecamp Update

Astrochemistry: Hubble and JWST Observe Star Formation in The Carina Nebula

Mapping the Historical Roots of Astrobiology: A Reference Publication Year Spectroscopy (RPYS) Analysis

The Agentic Observer Hackathon: Autonomous Decision-making in Simulated Astronomical Surveys

Tracking The Evolution of sub-Neptunes. I. Gyrochronology of Planet Hosting Stars