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Sub Neptune

All articles tagged with #sub neptune

space4 days ago•12 min saved

Sub-Neptunes: The Galaxy’s Most Common Planet Type, Yet Absent from Our Solar System

Sub-Neptunes—planets larger than Earth but smaller than Neptune—emerge as the Galaxy’s most common type, yet no such world orbits the Sun. Their interiors can range from rocky cores with thin hydrogen envelopes to water-rich or thick atmospheres, and similar bulk densities can hide very different compositions. A radius gap between roughly 1.5–2 Earth radii helps constrain formation, but atmospheric data are still muddled by clouds and hazes, making interiors hard to pin down. The upcoming JWST and next-generation telescopes should sharpen atmospheric measurements and population studies, shedding light on planet formation and why our Solar System is missing this dominant class.

via Space Daily|

#exoplanets #gj1214b #jwst

science1 month ago•72 min saved

Earth-like cores may be the oddity in the galaxy's most common planets

A new study argues that the galaxy's most common planets—sub-Neptunes—may not have Earth-like layered interiors with a distinct metallic core and silicate mantle. If these planets accrete more than about 1% hydrogen by mass, hydrogen, iron, and silicate can mix into a single, homogeneous interior, changing how they cool, hold onto atmospheres, and evolve their radii. This could explain features like the radius gap and how radii relate to orbital period, and it offers testable predictions for JWST observations, though the model rests on extrapolations of material behavior under extreme pressures. In short, Earth-like cores might be the exception rather than the rule in the galaxy.

via Space|

#exoplanets #hydrogen-miscibility #planetary-interiors

space4 months ago•6 min saved

Twice-Earth-Sized Hot Sub-Neptune TOI-5734 b Uncovered

An international team using TESS and HARPS-N confirmed TOI-5734 b, a hot sub-Neptune about 2.1 Earth radii and 9.1 Earth masses orbiting the young K-dwarf TOI-5734 every 6.18 days at roughly 0.06 AU (about 106 light-years away). With an equilibrium temperature around 688 K, the planet lies near the upper edge of the radius valley and is likely rocky with a largely stripped atmosphere, though a water-world scenario cannot be ruled out. The discovery, described in a February 2026 arXiv paper (DOI 10.48550/arxiv.2602.18108), leveraged three TESS sectors and HARPS-N data to illuminate atmospheric loss and inward migration in close-in exoplanets.

via The Daily Galaxy|

#exoplanets #harps-n #space

space5 months ago•75 min saved

Stellar radiation sculpts four young planets into super-Earths

Astronomers weigh four young, bloated planets around the infant star V1298 Tau and find they are extremely low density and actively losing their atmospheres to photoevaporation. Using transit timing variations, the team shows the planets are on track to shed most of their atmospheres, evolving into rocky super‑Earths or mini-Neptunes, suggesting a common outcome for such compact planetary systems.

via Space|

#exoplanets #photoevaporation #space

science9 months ago•4 min saved

New Study Suggests Earth and Many Exoplanets Are Less Unique Than Previously Thought

New research indicates that planets outside our solar system, including the exoplanet K2-18b, contain far less surface water than previously believed, challenging earlier theories of water-rich worlds and suggesting Earth may be more typical than extraordinary. The study highlights the importance of chemical interactions between planetary atmospheres and interiors in determining water content, which has implications for the search for extraterrestrial life.

via SciTechDaily|

#astrobiology #exoplanets #planetary-formation

science10 months ago•4 min saved

Steam Worlds and Sub-Neptunes: New Frontiers in the Search for Extraterrestrial Life

Scientists have developed a new model to better understand 'steam worlds,' planets too hot for liquid water and filled with water vapor, which could help in the search for habitable planets. The model considers exotic water states like supercritical water and superionic ice, and is relevant for interpreting observations from telescopes like JWST and future missions like ESA's PLATO. This research enhances our understanding of the most common types of exoplanets and their potential for hosting life.

via Space|

#exoplanets #planetary-modeling #science

science1 year ago•4 min saved

Webb Telescope Finds Water Vapor on a Small Exoplanet

NASA's James Webb telescope detected water vapor on the small, hot exoplanet TOI-421 B, a sub-neptune with a clear, hydrogen-rich atmosphere lacking methane and carbon dioxide, challenging previous assumptions about such planets' atmospheres and offering new insights into their formation and evolution.

via Earth.com|

#atmosphere #exoplanet #science