[astro-ph.EP] We report observations of comet 81P/Wild 2, target of the Stardust sample return mission, on UT 2023 March 20 and 24 at a heliocentric distance (rH) of 1.85 au […]
astro-ph.EP
![In top panels transits of TOI1408 b (left) and c (right) are shown along with their best fitting models (computed for one of likelihood maxima). In panels below the corresponding binned residuals and their uncertainties are plotted. Notice that there are a few occurrences when planets b and c transits partly overlapped with each other; in such a case all transit curves are plotted in the same graph. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/TOI-1408.png?resize=1200%2C720&ssl=1)
Posted inExoplanets, -moons, -comets
TOI-1408: The Limb Darkening Models, Photometric And Doppler Noises, And The Exoplanetary System
[astro-ph.EP] We perform a self-consistent analysis of Doppler and photometric TESS and ground-based transit observations available for TOI-1408, known to host a system with two planets orbiting near 2:1 mean-motion […]
Posted inExoplanets, -moons, -comets
Hybrid Worlds Are The Commonest Outcome Among The M-dwarf Sub-Neptunes Characterised With JWST
[astro-ph.EP] The sub-Neptunes orbiting M dwarfs are usually assigned to one of two classes: rocky cores beneath primordial hydrogen, or volatile-rich bodies formed beyond the water-ice line.
![Simulated climates and observables for CO2-rich planets near the outer edge of the habitable zone. The illustration on the right depicts a potentially habitable world orbiting a Sun-like star. The teal point in the lower left section of the panel marks the orbital location of such a planet within the OHZ, and the corresponding reflected light spectrum that could be observed via direct imaging is shown in teal in the middle, left section of the panel. The upper left section of the panel shows an illustration of the same planet in a globally frozen state located just beyond the habitable zone. Its orbital position (lower left) and reflected light spectrum (middle) are shown in white. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/High-CO2.png?resize=1200%2C721&ssl=1)
Posted inHabitable Zones
High-CO2 Climates And Observables In The Outer Habitable Zone
[astro-ph.EP] The habitable zone (HZ) is a fundamental concept used to guide our search for temperate exoplanets with stable surface liquid water that would sustain remotely detectable biosignatures.
Posted inExoplanets, -moons, -comets
Detecting Extragalactic Exoplanets With Fast Radio Burst Nanolensing
[astro-ph.EP] Fast Radio Bursts (FRBs) are spatially and temporally compact sources at cosmological distances. As background sources, they will be uniquely sensitive to the gravitational lensing of exoplanets outside of […]
![SpeX SXD spectrum of TOI-6981. The target spectrum (red) is shown alongside that of the M3.5V standard Luyten’s Star (grey), offset vertically for clarity. Regions of strong telluric absorption are shaded, and strong M-dwarf spectral features are indicated. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/TOI-6981.png?resize=1200%2C718&ssl=1)
Posted inExoplanets, -moons, -comets
TOI-6981 b: A Transiting Sub-Neptune At The Water Ice Line
[astro-ph.EP] We present TOI-6981 b, a cold (Teq= 170.0 +/-4.5 K, assuming an Earth-like albedo) sub-Neptune (Rb=2.40+/-0.10 R⊕) on a 60.8 day orbit around around its M4-type host star (R*=0.304 […]
![Transmission spectra of TRAPPIST-1 c from the four JWST/NIRSpec PRISM epochs (4-pixel bins, 0.8–5.0 𝜇m), offset vertically by 200 ppm per epoch for clarity and colour-coded by date, with the inverse-variance-weighted mean spectrum (black, plotted at its true depth). Grey bands mark the stellar H2O features near 1.4 and 1.85 𝜇m. The dotted line marks 2.0 𝜇m, the boundary of the region where the contamination is strongest (Section 3). The 2023 November 8 visit contains a flare during transit and the 2024 July 9 visit shows activity outside transit (Section 2.5). -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Detecting.png?resize=1200%2C716&ssl=1)
Posted inAstronomy & Telescopes
Detecting Atmospheres In The Presence Of Stellar Contamination: An Empirically Calibrated Framework Applied To Four JWST/NIRSpec PRISM Transits Of TRAPPIST-1c
[astro-ph.EP] Transmission spectroscopy of rocky exoplanets orbiting late M dwarfs is limited by stellar contamination rather than photon noise.
![Final semi-major axes and masses for all objects produced in simulations with regular disks. The left panel shows objects produced in disks with low C/O ratios and the right one shows planets in high C/O ratio disks. The dash-dotted line shows the initial mass of planestesimals in our simulations while the dotted line shows the initial mass of planetary embryos. We consider planets to be anything at or above the initial embryo mass, fragments to be anything below the initial planetesimal mass, and planetesimals to be any object at or above the initial planetesimal mass but below the initial embryo mass. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Correlations.png?resize=1200%2C719&ssl=1)
Posted inExoplanets, -moons, -comets
Correlations Between The Carbon-to-Oxygen Ratio and the Orbital and Physical Properties of Exoplanets
[astro-ph.EP] Studies suggest that protoplanetary disks around stars with high carbon-to-oxygen (C/O) ratios can produce terrestrial planets with carbon-dominated compositions instead of silicon-dominated ones.
![Median protoplanetary disk composition predicted by the chemical model at different metallicities [Fe/H]. LEFT: Median overall composition. RIGHT: Median refractory composition. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/On-the.png?resize=1200%2C719&ssl=1)
Posted inInterstellar
On The Compositions Of Interstellar Objects
[astro-ph.EP] As physical samples of distant planetary systems, the compositions of interstellar objects (ISOs) should correlate with the properties of their diverse parent stars.
Posted inExoplanets, -moons, -comets
Atmospheric Dynamics And Variability Of Periodically Irradiated Tidally Locked Planets
[astro-ph.EP] Time-variable stellar heating may create new climate states, such as permanently hot or cold hemispheres, on asynchronous planets. Planets on eccentric orbits, circumbinary planets and planets on polar orbits […]