Protoplanetary Disk – Page 3 – My WordPress Site

The posteriors were derived by applying the planetary evolution and mass loss framework of ref. 32 to our measured masses and radii for planets c (red), d (orange), b (green) and e (blue). Left, initial envelope mass fraction versus core mass. Right, initial Kelvin–Helmholtz cooling timescale versus core mass. Contours show the 1σ and 2σ credible regions. (Note that the jagged appearance of some contours is a numerical artefact of the discrete core mass grid used in our analysis; see Methods for more details). The vertical dotted line in the right panel at 10 Myr marks the approximate upper limit for standard high-entropy formation models. These models are strongly disfavoured for the inner planets c and d, whereas for the less-irradiated outer planets b and e, the method lacks the statistical power to distinguish between high- and low-entropy scenarios. -- Nature

Astrogeology, Astronomy & Telescopes, Exoplanets, -moons, -comets

A Young Progenitor For The Most Common Planetary Systems In The Galaxy

by Keith CowingJanuary 16, 2026January 16, 2026

Reference and sample spectra of N2 ice

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Icy Worlds, Imaging & Spectroscopy, Interstellar

Broadband Spectroscopy Of Astrophysical Ice Analogues: IV. Optical Constants Of N2 Ice In The Terahertz And Mid-infrared Ranges

by Keith CowingJanuary 14, 2026January 14, 2026

evolution of surface density (

Astrogeology, Exoplanets, -moons, -comets

Formation Of Multi-planetary Systems Via Pebble Accretion In Externally Photoevaporating Discs In Stellar Clusters

by Keith CowingJanuary 14, 2026January 14, 2026

Schematic illustration of the properties and relative distribution of µm-size dust, mm grains, and molecular gas in the two cavity types

Astrochemistry, Astrogeology, Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Interstellar

Protoplanetary Disk Cavities With JWST-MIRI: A Dichotomy In Molecular Emission

by Keith CowingJanuary 9, 2026January 9, 2026

A sketch of the proposed scenario. Oxidized planetesimals decay to near 1 au, accreting onto proto-Earth and proto-Venus as well as forming Mars. Some oxidized planetesimals and aubrite-like planetesimals remain and will be implanted during the giant planet instability into the asteroid belt as the parent bodies of NC iron meteorites and aubrites, where they join the later-formed chondrites (checkered circles) and C-type asteroids (purple circles) delivered from beyond Jupiter. -- astro-ph.EP

Astrogeology, Exoplanets, -moons, -comets, Habitable Zones

Two-source Terrestrial Planet Formation With A Sweeping Secular Resonance

by Keith CowingJanuary 8, 2026January 8, 2026

Image of Dracula's Chivito captured by Hubble's WFC3 instrument

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Interstellar

Hubble Reveals The Largest Chaotic Birthplace of Planets Yet Discovered

by Keith CowingDecember 31, 2025December 31, 2025

Graphic of the proposed scenario of sublimation in a disk with a warm dust trap, viewed from the side, based on van der Marel et al. (2021b). If the bulk of the dust content is located in a dust trap inside the CO snowline at 30 K, this implies that fragments of its icy pebbles can be transported vertically to the higher disk layers above the H2O snow surface at 150 K, and sublimate their icy content into the gasphase, where it becomes observable. If the bulk of the pebbles is located outside the CO snowline, its icy layers may remain frozen out and its contents are not revealed in the gas phase. Such a scenario may also apply to PAHs, which is the hypothesis of this work. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar

Observational Evidence For A Possible Link Between PAH Emission And Dust Trap Locations In Protoplanetary Disks

by Keith CowingDecember 30, 2025December 30, 2025

NanoSIMS ratio and ion images (top images) of a region containing a 17O-rich presolar silicate grain (arrows). The elemental maps and spectra from SEM-EDX analysis confirm the grain is a ferromagnesian silicate. -- Nature Astronomy via PubMed

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Comets and Asteroids, Imaging & Spectroscopy, Meteorites & Asteroids, Missions & Hardware, Sample Return

The Variety And Origin Of Materials Accreted By Bennu’s Parent Asteroid

by Keith CowingDecember 24, 2025December 24, 2025

This illustration shows a star surrounded by a protoplanetary disk. A new study uses data from NASA's Spitzer Space Telescope and four ground-based telescopes to determine the distance from a star to the inner rim of its surrounding protoplanetary disk. Researchers used a method called "photo-reverberation," also known as "light echoes.-- NASA (source)

Astrogeology, Imaging & Spectroscopy, Stellar Cartography

Bridging Stellar Evolution And Planet Formation: From Birth, To Survivors Of The Fittest, To The Second Generation Of Planets

by Keith CowingDecember 23, 2025December 23, 2025

This composite Hubble Space Telescope image shows the debris ring and dust clouds cs1 and cs2 around the star Fomalhaut. Fomalhaut itself is masked out to allow the fainter features to be seen. Its location is marked by the white star. Image: NASA, ESA, Paul Kalas (UC Berkeley); Image Processing: Joseph DePasquale (STScI)

Astrogeology, Astronomy & Telescopes, Comets and Asteroids, Exoplanets, -moons, -comets, Fomalhaut, Imaging & Spectroscopy, Stellar Cartography

Hubble Sees Asteroids Colliding at Nearby Star for First Time

by Keith CowingDecember 19, 2025December 19, 2025