![Radial velocity timeseries of K2-3 used in the analysis. Here the second dimension for the multi-dimensional quasi-periodic gaussian process kernes used the D2V activity indicator to disentangle the stellar activity from the Keplerian signals. The Keplerian models for all three planets are assumed to be circular orbits for this figure (Model 1 in Table C.3). The various instruments used in the analysis are colour coded. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/Uncovering.png?resize=1200%2C719&ssl=1)
[astro-ph.EP] The K2-3 system is one of the most unique planetary systems as it features three transiting sub-Neptunes in decreasing order of radii, spanning the radius valley.
radius valley
![Geometry of the LTT 3780 planetary system at the time of our radio technosignature observations. The left panel shows the sky-plane (X–Y) view as seen from Earth, while the right panel shows the top-down (X–Z) view of the system. The orbits of planets b (blue) and c (green) are shown relative to the host star (yellow). Our observations from the ATA, mentioned in Table 1 on 5th November 2025, were timed to coincide with a planet–planet occultation (PPO), when planet b passes behind planet c along the line of sight, providing a unique configuration to search for radio technosignatures during mutual planetary alignment.-- [astro-ph.IM]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/A-Search-For.png?resize=1200%2C719&ssl=1)
Posted inSETI & Technosignatures
A Search For Narrowband Technosignatures From LTT 3780 With The Allen Telescope Array And The Karl G. Jansky Very Large Array
[astro-ph.IM] The LTT3780 system hosts two known exoplanets-LTT3780b, a rocky super-Earth, and LTT3780c, a temperate sub-Neptune-orbiting a nearby M dwarf on opposite sides of the radius valley. LTT3780c has been […]
Posted inAstrogeology, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Lava / magma ocean / Volcanic Worlds, Press Release
A Gem System With A Lava World And A Habitable Zone Sub-Neptune Orbiting TOI-1752
The Transiting Exoplanet Survey Satellite (TESS) has delivered a large number of transiting planet candidates around nearby stars by identifying periodic decreases in stellar brightness. A top-down view of the […]
Posted inExoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Stellar Cartography
Insights Into The Exoplanet Radius Valley From Host-Star Ages, Activity, Chemistry, And Birth Radius
The radius valley, a bimodal feature in the size distribution of close-in small exoplanets, is widely interpreted as a signature of atmospheric loss and therefore provides a key constraint on […]
Posted inAstronomy & Telescopes, Exoplanets, -moons, -comets, Ice Giant, Icy Worlds, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography
Elevated Eccentricities In The Radius Valley Hint At Water-Rich Mini-Neptunes
While recent planet-formation models broadly reproduce the observed population of super-Earths and mini-Neptunes, as well as the bimodal radius distribution (the “radius valley”), it remains unclear whether all these planets […]
Posted inAstronomy & 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
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 […]
Posted inAstrochemistry, Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Status Report
JWST COMPASS: A NIRSpec G395H Transmission Spectrum of Radius Valley-Dweller TOI-260 b
We present a JWST/NIRSpec G395H transmission spectrum of TOI-260 b, a Teq∼490 K, Rp=1.76R⊕ planet.
Posted inAstrogeology, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Ice Giant, Status Report, Water/Hycean Worlds & Oceanography
The Radius Cliff is a Waterfall: Explaining Sub-Neptune Exoplanets With Steam Worlds
The demographics of Kepler planets provide a key testbed for models of planet formation and evolution, particularly for explaining the radius valley separating super-Earths and sub-Neptunes.
Posted inExoplanets, -moons, -comets, Status Report, Stellar Cartography
Architectures of Exoplanetary Systems. IV: A Multi-planet Model for Reproducing the Radius Valley and Intra-system Size Similarity of Planets around Kepler’s FGK Dwarfs
The Kepler-observed distribution of planet sizes have revealed two distinct patterns: (1) a radius valley separating super-Earths and sub-Neptunes and (2) a preference for intra-system size similarity.
Posted inAstronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report
An Ultra-Short Period Super-Earth and Sub-Neptune Spanning the Radius Valley Orbiting the Kinematic Thick Disk Star TOI-2345
A crucial chemical link between stars and their orbiting exoplanets is thought to exist. If universal, this connection could affect the formation and evolution of all planets. Therefore, this potential […]