[astro-ph.EP] The formation of Uranus and Neptune remains poorly constrained largely due to uncertain deep elemental abundances. Carbon monoxide (CO), a disequilibrium species in the upper troposphere, provides an indirect […]
astro-ph.EP
Posted inPLATO
Habitable-zone Earths At The Detection Frontier: Measured Completeness And False-alarm Rate Of A Transit Pipeline For The PLATO M-dwarf Sample
[astro-ph.EP] The PLATO mission will observe its first long-pointing field, LOPS2 (Long-duration Observation Phase, South field), for at least two years, bringing the habitable zones (HZ) of its M-dwarf sample […]
![Planets that will be observed with MIRI in transit, in JWST Cycles 1-5. As mentioned in section 5, we see a wide variety of planet sizes and equilibrium temperatures. The currently published planets are shown in black dots, and listed in Table 1 and Figure 1. We have ommitted the white dwarf planet WD 1856 b (Teq = 160K, Rp = 10.2R⊕, cycle 4), as well as the disintergrating planets K2-22 b (see section 2.1) and BD+05 4868 A b (Teq = 1820K, unknown Rp, cycle 4). -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/A-Homogeneous.png?resize=1200%2C720&ssl=1)
Posted inExoplanets, -moons, -comets
A Homogeneous Survey Of JWST MIRI Transmission Spectra Of 10 Exoplanets
[astro-ph.EP] The launch of JWST has enabled unprecedented atmospheric characterization of exoplanets. In particular, the JWST-MIRI instrument in the mid-infrared enables probing of molecular species that are harder to detect […]
![Phase-dependent (colors) apparent albedo spectra from our updated rfast model for an ocean-covered Earth and assuming 75% cloud coverage (left). The equivalent figure adapted from the high-fidelity Earth simulation data of Ryan & Robinson (2022) are shown for comparison (right). All spectra are at a resolving power (λ/∆λ) of 140. Deeper water bands in the rfast simulations are due to this model only including lower-atmospheric clouds, whereas the Ryan & Robinson (2022) simulations include high-altitude clouds that have lower contrast in gas absorption bands (as they obscure the deep atmosphere). -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/Retrieving.png?resize=1200%2C717&ssl=1)
Posted inWater/Hycean Worlds & Oceanography
Retrieving Ocean Glint Reflectance Signatures From Directly Imaged Earth-like Exoplanets
[astro-ph.EP] Future space telescopes searching for extraterrestrial life require methods to detect environments that can potentially support life.
![Map of the (top) phase ratio I(5◦ )/I(15◦ ) at 2.0 µm and (bottom) phase reddening (with spectral slope computed between 2.1 µm and 2.5 µm). The maps were computed using a 10◦ × 10◦ grid at the Ryugu surface. The particularly high phase ratio and low phase reddening values for some grid elements located at latitude above 10◦N are due to a narrower phase angle range (see Appendix F, Fig. 20). All grid elements above this latitude were discarded for the computation of the average east and west properties.-- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/Updated.png?resize=1200%2C720&ssl=1)
Posted inImaging & Spectroscopy
Updated in-flight Calibration Of The Hayabusa2/NIRS3 Spectrometer: New Global Near-infrared Photometric Properties Of Asteroid (162173) Ryugu
[astro-ph.EP] The Near InfraRed Spectrometer (NIRS3) onboard Hayabusa2 observed asteroid (162173) Ryugu, searching especially for signatures of water-bearing minerals.
Posted inExoplanets, -moons, -comets
Mass Constraints For The K2-223 System Planets: An Ultra-short-period sub-Earth, A Short-period Super-Earth, And A Tentative Long-period Giant Planet
[astro-ph.EP] We present mass constraints of two short-period, terrestrial-sized planets transiting K2-223, based on high-precision radial velocity measurements from HARPS-N and ESPRESSO, as well as a tentative indication of an […]
![LT solution with 2036 launch. Continuous thick curve: trajectory, Short segments: thrust law, Dashed lines: planet and comet orbits. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/Double-Gravity.png?resize=1200%2C718&ssl=1)
Posted inComets and Asteroids
Double Gravity-Assist Rendezvous Trajectory to Halley’s Comet Using Deep-Space Low Thrust
[astro-ph.EP] The perihelion of comet 1P/Halley in 2061 is an excellent chance to revisit this object of outstanding scientific and cultural relevance. During its 1986 approach to the Sun, it […]
![Plot of the frequency vs. diameter for all asteroids with known or estimated rotation period with quality code 𝑈 ≥ 1. File data from the ALCDB of 1 Oct 2023, the last release (https://alcdef.org/). The two near-Earth asteroids, 2000 RD34 and 2000 DN8 (both with 𝑈 = 1), are shown together with the five LSFR from Rubin observations (red) and the candidate LSFR or almost candidate (due to borderline diameter as for 2015 RG36 and 2024 WB), which we have characterized at the Loiano Astronomical Station, managed by INAF-OAS in Italy (cyan). The curves for the rubble pile model with cohesion strength are from Eq. 12 (Sánchez and Scheeres, 2014). Our candidates LSFR has a cohesive strength between 102–104 Pa. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/Photometric.png?resize=1200%2C721&ssl=1)
Posted inComets and Asteroids
Photometric Characterization Of Near-Earth Asteroids: Rotation, Taxonomy, And Candidate Evidence For Internal Cohesion
[astro-ph.EP] We present the results of a survey of previously uncharacterized near-Earth asteroids (NEAs) conducted between the second half of 2024 and the first months of 2026 using broadband BVRcIc […]
![Dereddened Gaia CMD with PARSEC isochrones overplotted. Black points show Gaia DR3 stars corrected for extinction and reddening using band-specific coefficients. Solid curves show isochrones spanning ages from 1 to 13 Gyr at the reference metallicity. The dotted curves highlight 1 Gyr isochrones computed at the lower (-0.4 dex) and upper (+0.4 dex) metallicity values in the sample, illustrating the range of CMD permitted by the observed metallicity distribution. This comparison demonstrates the impact of metallicity on isochrone placement relative to the data. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/Precise.png?resize=1200%2C718&ssl=1)
Posted inExoplanets, -moons, -comets
Precise Stellar Age Constraints and Habitable Zone Evolution in Exoplanet Systems
[astro-ph.EP] Accurate stellar ages are fundamental to interpreting the evolutionary histories of habitable zone (HZ) planets. Because stellar luminosity evolves over time, HZ boundaries migrate outward, meaning that present-day HZ […]
![Schematics of a HAeBe star accreting material from its protoplanetary disc with an ongoing giant planet formation. The giant planet opens a disc gap, preventing the larger dust grains from moving inwards. The HAeBe star has a convective core (red), a radiative envelope (blue), and the stellar photosphere (yellow).-- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/The-refractory.png?resize=1200%2C718&ssl=1)
Posted inAstrochemistry
The Refractory Fraction Of Phosphorus In Planet-forming Discs
[astro-ph.EP] Context. Phosphorus (P) is an essential element for life on Earth and a potential tracer of planet formation history. However, there has been no detection of P-bearing molecules in […]