![Images acquired on 2019 October 4 (left) and 27 (right) with LDT. The top row show stacks of r and CN images, respectively. The bottom row shows the same images enhanced by subtraction of an azimuthal median profile. The enhanced CN images have been smoothed with a Gaussian profile to better reveal the faint underlying structure. A compass indicating north (N), east (E), the anti-sunward direction (−⊙), and the anti-velocity vector (−v) are overlaid on the r panels, while a scale bar showing a distance at the comet of 20,000 km is given on the CN panels (1 arcsec corresponds to 2134 km on October 4 and 1814 km on October 27). All four panels for a given night have the same orientation and physical scale at the comet. The October 4 image is a single frame and shows several artifacts that could not be removed without a median combination include several bright pixels in the CN frame (yellow) and a bad column in all frames (black diagonal line). On October 4, a bright star is seen near the left edge of the r frames and as a diagonal (yellow) line in the upper right in CN. Two faint trailed stars are visible in the r images on October 27. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/The-Highly.png?resize=1200%2C720&ssl=1)
[astro-ph.EP]. We report on imaging, spectroscopy, and narrowband photometry of interstellar comet 2I/Borisov obtained at Lowell Observatory from 2019 September 13 to December 16.
astro-ph.EP
Posted inAstrogeology
Volatile Depletion In Rocky Planets As A Chemical Fingerprint Of Hybrid Accretion
[astro-ph.EP] Volatile depletion in rocky planets relative to their host stars is commonplace in both the Solar System and exoplanetary systems, yet the connections between planet formation and composition remain […]
Posted inExoplanets, -moons, -comets
An Evolving Cosmic Shoreline and Sandbar Bounding the Rocky Airless Valley
[astro-ph.EP] Recent JWST observations challenge the traditional ‘cosmic shoreline’ from both sides, revealing thick volatile atmospheres on the hottest close-in ‘lava worlds,’ where irradiation should drive the most extreme escape, […]
Posted inSpace Weather & Heliophysics
Preparing For The Early eVolution Explorer: The Impact of Flare Temperature on Ozone Column Depth in Earth-Like Atmospheres
[astro-ph.EP] Atmospheric photochemical models incorporating the impacts of stellar flares often assume a ∼9,000 K spectrum at ultraviolet-optical wavelengths.
Posted inExoplanets, -moons, -comets
Transit Searches for Habitable-Zone Exoplanets with Artificial Intelligence
[astro-ph.EP]. Searching for Earth-sized planets in stellar habitable zones ultimately means finding a small number of very shallow, widely separated transits in noisy light curves.
![Differences in the TLS effect for the TRAPPIST-1 planets for our minimal two-zone model. The left panel shows a representative diagram of the stellar surface with increased spottedness in the polar regions. Lines are drawn to represent the center of the transit chord for each of the TRAPPIST-1 planets. As a representative example, the width of planet b’s transit chord is shaded in blue. In the right panel, the relative transit depth is shown assuming only stellar heterogeneity made up of cooler regions (upper) and hotter regions (lower) with no contribution from a planetary atmosphere over the wavelength range relevant to JWST NIRSpec/PRISM. The higher impact parameter planets (f, g, and h) are less impacted by the TLS effect than the lower impact parameter planets given our choice of zonal boundary. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Leveraging-Impact.png?resize=1200%2C717&ssl=1)
Posted inTRAPPIST-1
Leveraging Impact Parameter to Mitigate the Transit Light Source Effect: Early Insights from TRAPPIST-1
[astro-ph.EP] Stellar activity complicates exoplanet transmission spectra, particularly for smaller planets around M dwarfs with JWST.
![Sunburst diagrams describing the evolution of the inner planets (top) and the outer giant planets (bottom) in the DAG simulations. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Effects-of.png?resize=1200%2C717&ssl=1)
Posted inExoplanets, -moons, -comets
Effects Of Outer Giant Planets On In Situ Formation Of Inner Super-Earths
[astro-ph.EP] Recent studies have found an observational correlation between the presence of outer giant planets and inner super-Earths, which implies that outer giants do not suppress the formation of super-Earths.
![Normalized magnetospheric standoff distance rM/rpl as a function of the planetary magnetic field and the total stellar pressure for Modern Earth (left panel) and Early Earth (right panel) across the HZ of the host star. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/The-impact-of.png?resize=1200%2C714&ssl=1)
Posted inExoplanets, -moons, -comets
The Impact Of Tidal Locking On Earth-like Planetary Dynamos
[astro-ph.EP] We investigate how tidal locking affects the planetary dynamo and the magnetospheres of Earth-like planets orbiting the habitable zones of M dwarfs.
Posted inExoplanets, -moons, -comets
ADORA: A Differentiable Optical Modeling And Astrometric Retrieval Framework For SHERA
[astro-ph.EP] Motivated by recent observations suggesting rings found in debris disks are wider than those in protoplanetary disks, we consider a picture in which planetesimals formed in radially narrow dust […]
![Upper Panels. Maps of N × ρ for ortho-H2O and para-H2O, the derived OPR, and Trot(H2O) for the 6 µm band measured on February 28. Note that N for each species has been corrected for the derived OPR. Lower Panels. As in the upper panels for the 2.6 µm H2O bands measured on March 1. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/JWST-Spatial.png?resize=1200%2C727&ssl=1)
Posted inComets and Asteroids
JWST Spatial-Spectral Mapping of Green Comet C/2022 E3 (ZTF)
[astro-ph.EP] We report a survey of molecular emission from cometary volatiles using the James Webb Space Telescope (JWST) toward Oort cloud comet C/2022 E3 (ZTF) carried out on UT 2023 […]