![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.
Astronomy & Telescopes
Posted inExoplanets, -moons, -comets
Hidden Worlds: A Non-transiting Candidate Planet In The Neptunian Desert Around The Solar-type Pulsator KIC 9139163
[Astronomy & Astrophysics] Close-in substellar companions experience strong tidal and magnetic interactions with their host stars and are therefore subject to fast orbital evolution.
Posted inExoplanets, -moons, -comets
Pandora Mission Begins A Study Of Exoplanets And Their Host Stars
[NASA] Pandora, NASA’s newest exoplanet mission and the first satellite to launch through the agency’s Astrophysics Pioneers program, is now making unique observations of worlds beyond our solar system and […]
![Earth biosignatures through time and their reflected light spectra. The left subplot shows estimates of Earth’s bulk atmospheric composition through time (advancing from top to bottom), and the figures on the right show the corresponding reflected light spectra considered in this study. Key absorption features for biosignature gases (O3, O2, CH4) and suggested long- and short-wavelength cutoffs are highlighted (as discussed further in Sections 3 and 4). Adapted from National Academies of Sciences, Engineering, and Medicine (2021) and LUVOIR and HabEx Final Reports (LUVOIR Team, 2019; Gaudi et al., 2020). -- [Astrobiology (Journal)]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Wavelength.png?resize=1200%2C719&ssl=1)
Posted inBiosignatures & Paleobiology
Wavelength Requirements for Life Detection via Reflected Light Spectroscopy of Rocky Exoplanets
[Astrobiology (Journal)] Searching for signs of life is a primary goal of the Habitable Worlds Observatory (HWO). However, merely detecting oxygen, methane, or other widely discussed biosignatures is insufficient evidence […]
![JWST Cycle 6 -- [NASA / STSCI]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/JWST-Cycle-6.jpg?resize=1200%2C720&ssl=1)
Posted inPolicy
JWST Cycle 6 Call for Proposals Policy Update [China]
[NASA / STSCI] Proposals involving only investigators based in the People’s Republic of China (PRC) or involving only PRC-based and U.S. investigators are subject to the NASA restriction on bilateral […]
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.
![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 […]
![The timescale required for a 10 M⊕ring of planetesimals around a 1 M⊙ star to radially diffuse 0.1 M⊕ into the inner 0.5 au. The planetesimal density is assumed to be 4 g cm−3 . The black dashed line shows the boundary where the inner edge is just reachable by the radially diffusing disk, below which the escape velocity is less than the critical escape velocity (v0.5au) and planetesimals are not deliverable at this level. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Substructure.png?resize=1200%2C715&ssl=1)
Posted inExoplanets, -moons, -comets
Substructure Evolution From Protoplanetary To Debris Disks Driven By Mutually Gravitating Planetesimals And Implications On Kepler Resonances And Free-floating Planets
[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 […]