astro-ph.EP Archives

Distribution of our found planets in period–radius space (left) and instellation–radius space (right). Each planet and its associated errors are are marked with the red points, while the background grid shows the peak occurrence rate fpeak in each bin of the grid. Regions where our average sensitivity is < 10% are highlighted in pink. The top and leftmost panels show the cumulative fpeak distributions from each map. We note that these distributions are not representative of the full occurrence rates, and differ because planets may find themselves in different regions of sensitivity based on their instellation and period. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Gas Giants, Ice Giant, Status Report, Water/Hycean Worlds & Oceanography

TESS Planet Occurrence Rates Reveal the Disappearance of the Radius Valley Around Mid-to-Late M Dwarfs

by Keith CowingMarch 2, 2026March 2, 2026

We present the deepest systematic search for planets around mid-to-late M dwarfs to date. We have surveyed 8134 mid-to-late M dwarfs observed by TESS with a custom built pipeline and […]

Schematic diagram for classifying planets according to their masses and orbital periods. The various categories of planets are labelled. The boundary masses are shown on the right. The grey points in the background are the secondary components included in TEPCat. -- astro-ph.EP

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

TEPCat: The Transiting Extrasolar Planet Catalogue

by Keith CowingMarch 2, 2026March 2, 2026

Transiting extrasolar planets are extraordinarily valuable for understanding the characteristics and formation of planets, because they are the only exoplanets whose physical and orbital properties can be measured to high […]

Recovery of an injected signal for the cloud-free case of V1298 Tau b on a vrest − KP grid for each synthetic night simulated using Ratri for the case of (top row) the optimistic detrending scenario and (bottom row) the non-reprocessing scenario where the SVD+MLR based detrending is followed by cross-correlation with a template model with no reprocessing performed on it. The injected signal is successfully detected in all three nights for the optimistic detrending scenario. For the non-reprocessing scenario, the injected signal is successfully detected only in Night 3 but with weaker constraints on KP compared to the optimistic detrending case. For the other two nights, the signal is either completely removed by the detrending scenario resulting in a non-detection (Night 1) or a detection at a much higher value of KP compared to the injected value (Night2). For more discussion about confidence intervals and what constitutes a detection, please see Section 2.4.3. -- astro-ph.EP

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

Probing The Atmospheres Of Young Long-Period Sub-Neptune Progenitors With ELT/ANDES

by Keith CowingMarch 1, 2026March 1, 2026

High-resolution cross-correlation spectroscopy (HRCCS) has emerged as a powerful technique for detecting and characterizing exoplanet atmospheres from the ground.

Free retrieval results (top two panels) and cross sections of considered chemical species (bottom two panels) from our investigation of the 3.17 µm feature. Free retrievals were conducted on the combined Tiberius (top, blue) and Eureka! (middle-top, pink) reductions. The 1σ range in retrieved spectra are shown in the colored bands for all considered species (red), all species except C2H2 and C2H4 (yellow), all species except for C2H2, C2H4, and C3 (green), all species except for C2H2, C2H4, C3, and NH3 (dark blue), and only the common species (H2O, CH4, CO2, CO, SO2, and H2S; light pink). -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Status Report

JWST COMPASS: A NIRSpec G395H Transmission Spectrum of Radius Valley-Dweller TOI-260 b

by Keith CowingFebruary 28, 2026February 28, 2026

We present a JWST/NIRSpec G395H transmission spectrum of TOI-260 b, a Teq∼490 K, Rp=1.76R⊕ planet.

A heatmap of Planck-weighted correlated-k tables to complement Figure 5 of PICASO 3.0 release in order to show any major differences between opacity and chemistry updates. The four panels correspond to Gauss points 1, 3, 5, and 7 (shown in the title of each panel). The dashed black lines correspond to Sonora-bobcat pressure-temperature profiles at increasing effective temperatures for reference (as labeled in the upper left panel) (Marley et al. 2021). All major features of the correlated-k tables remain the same between v3 and v4. -- astro-ph.EP

Atmospheres, Climate, Weather, Brown Dwarfs, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

PICASO 4.0: Clouds And Photochemistry In Climate Models Of Brown Dwarfs And Exoplanets

by Keith CowingFebruary 28, 2026February 28, 2026

We present a major update to the open-source atmospheric modeling package PICASO, designed for simulating the thermal structure and spectra of hydrogen-rich atmospheres of brown dwarfs and exoplanets.

Schematic representation of the effect of stellar contamination (TLS) with actual examples of the effect of TLS in simulated signals.

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

Efficient Reduction Of Stellar Contamination And Noise In Planetary Transmission Spectra Using Neural Networks

by Keith CowingFebruary 27, 2026February 27, 2026

Context: JWST has enabled transmission spectroscopy at unprecedented precision, but stellar heterogeneities (spots and faculae) remain a dominant contamination source that can bias atmospheric retrievals if uncorrected.

Spectral flux and exergy at the top of the atmosphere for three blackbody models, all normalized to the same bolometric flux 𝐹bol = 1361 W m2.Solid curves show 𝐹TOA,𝜆 and dashed curves 𝜂ex𝐹TOA,𝜆. The vertical line marks a PSII-like threshold at 𝜆thr = 690 nm, illustrating how the shortwavelength band available for high-Δ𝐺 photochemistry shrinks for M-type hosts. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Genomics, Proteomics, Bioinformatics, Habitable Zones, Plant Biology, Status Report

Photosynthetic Exergy I. Thermodynamic Limits For Habitable-zone Planets

by Keith CowingFebruary 26, 2026June 11, 2026

Photosynthesis is central to Earth’s biosphere and a prime candidate for sustaining complex life on habitable exoplanets, yet a thermodynamically consistent treatment of the work potential of stellar radiation at […]

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones, Radiation, Status Report

Topography-Induced Stationary Waves And The Onset Of Nightside Warming On Rocky Planets Around M-dwarf Stars

by Keith CowingFebruary 26, 2026February 26, 2026

Among potentially habitable worlds, rocky planets orbiting M dwarfs offer the most favorable prospects for atmospheric characterization, yet their climates may differ substantially from those of Earth analogs.

One hour stacked HATPI subtracted images of 3I/ATLAS from each of the nights on which 3I/ATLAS is formally detected with 3σ confidenc

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Interstellar, Status Report

HATPI Pre-Perihelion Time-series Photometry of the Interstellar Comet 3I/ATLAS

by Keith CowingFebruary 26, 2026February 26, 2026

HATPI is a recently commissioned time-domain facility at Las Campanas Observatory, Chile, that uses 64 wide-angle, 9.6 cm diameter lenses and back-illuminated CCDs, yielding a mosaic field-of-view of 7,100 square […]

Overview and performance of the LUMOS framework for biogenicity assessment. a, The LUMOS (Life Unveiled using Molecular Orbital Signatures) framework integrates amino acid abundance measurements with quantum chemical descriptors to evaluate biogenicity. First, the abundance of a set of amino acids is estimated, followed by the computation of molecular descriptors (e.g., HOMO–LUMO gap). These descriptors are then weighted by abundance using statistical features such as weighted variance. The resulting value is used to assess the confidence in biogenicity, informed by additional contextual data and environmental provenance. b, Heatmap of P(B|E), the confidence that a sample is biotic (B) given the observed weighted variance (evidence E) as a function of the number of amino acids measured. The prior P(B) is taken as 0.01. Color intensity reflects the biogenicity probability as determined by Bayesian inference applied to simulated distributions of biotic and abiotic samples. c, Criteria met by the LUMOS framework for distinguishing biotic from abiotic amino acid systems. -- astro-ph.EP

Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Genomics, Proteomics, Bioinformatics, Origin & Evolution of Life, Status Report

Distinguishing Life From Non-life Via Molecular Frontier Orbital Energy Gaps

by Keith CowingFebruary 25, 2026February 26, 2026

Amino acids (AAs) are a key target in the search for life beyond Earth due to their extensive role in the machinery of all known life, persistence over geologic timescales, […]

astro-ph.EP

TESS Planet Occurrence Rates Reveal the Disappearance of the Radius Valley Around Mid-to-Late M Dwarfs

TEPCat: The Transiting Extrasolar Planet Catalogue

Probing The Atmospheres Of Young Long-Period Sub-Neptune Progenitors With ELT/ANDES

JWST COMPASS: A NIRSpec G395H Transmission Spectrum of Radius Valley-Dweller TOI-260 b

PICASO 4.0: Clouds And Photochemistry In Climate Models Of Brown Dwarfs And Exoplanets

Efficient Reduction Of Stellar Contamination And Noise In Planetary Transmission Spectra Using Neural Networks

Photosynthetic Exergy I. Thermodynamic Limits For Habitable-zone Planets

Topography-Induced Stationary Waves And The Onset Of Nightside Warming On Rocky Planets Around M-dwarf Stars

HATPI Pre-Perihelion Time-series Photometry of the Interstellar Comet 3I/ATLAS

Distinguishing Life From Non-life Via Molecular Frontier Orbital Energy Gaps

How A Deep-sea Protein Adapts To An Extreme Environment

Fingerprints Inside Our Sun Could Reveal If It Once Swallowed A Planet

Climates Of Gl 514 b

Cosmic Radiation at Flight Altitudes Rises When the Sun Is Less Active

The History Of Enzyme Evolution Embedded In Metabolism