Protoplanet Archives

An X-ray image of NWA 12774. (Credit: Aaron Bell/CU Boulder)

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Comets and Asteroids, Impact events, Meteorites & Asteroids, Press Release, Sample Return

Rare Meteorite Provides Evidence Of A Giant Early Planet

by Keith CowingJune 17, 2026June 17, 2026

Four-and-a-half billion years ago, a massive world, possibly as big as the moon or even Mars, orbited our sun before crashing into another celestial body and shattering into rubble.

[LEFT] Final planet mass vs pebble flux across the snowline at time of insertion. Plots A and B are coloured by the planet’s initial and final semi-major axes respectively. Plot C is coloured by the planet’s insertion time 𝑡0, and plot D is coloured by the characteristic disk radius 𝑅0. Plot E is coloured by the disk’s 𝛼 parameter, and plot F is coloured by the fragmentation velocity 𝑣frag. All plots contain outlined numbered points, which correspond to the points numbered in Fig. 2. [RIGHT Final planet mass vs pebble flux across the snowline at 1 Myr. Plots A and B are coloured by the planet’s final and initial semi-major axes respectively. Plot C is coloured by the planet’s insertion time 𝑡0, and plot D is coloured by the characteristic disk radius 𝑅0. Plot E is coloured by the disk’s 𝛼 parameter, and plot F is coloured by the fragmentation velocity 𝑣frag. All plots contain outlined numbered points, which correspond to the points numbered in Fig. 2. -- astro-ph.EP

Astrochemistry, Astrogeology, Comets and Asteroids, Exoplanets, -moons, -comets, Status Report

Simulating The Interplay Between The Snowline Pebble Flux And Ongoing Planet Formation And Migration

by Keith CowingApril 18, 2026April 18, 2026

Pebble drift plays a central role in modern planet formation models. In this work we carry out planet formation simulations (including pebble accretion and migration) for a range of disc […]

HCN and millimeter dust continuum emission from the disc of HD 163296 as observed with ALMA.

Astrochemistry, Astrogeology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Circumplanetary Disk Candidate In The Disk of HD 163296 Traced By Localized Emission From Simple Organics

by Keith CowingJanuary 17, 2026January 17, 2026

Atacama Large Millimeter/submillimeter Array observations suggest that the disc of HD 163296 is being actively shaped by embedded, yet unseen protoplanets, as indicated by numerous gas and dust substructures consistent […]

Orbital evolution of protoplanets and changes in core density deficit and water content in atmosphere for (a) Case No.6, (b) No.7, (c) No.11, (d) No.12 (see Table 2). We show results with an atmospheric mass of Mmid. Early giant impacts in the inner region do not lead to atmospheric acquisition because the merged mass remains below the threshold for atmospheric capture (Mproto = 0.2 M⊕). Even in the presence of inclination, the core density deficit evolves in a multistage manner. As cases where planets with a value close to the Earth’s core density deficit was obtained, a planet with a final mass of 0.871 M⊕ and a core density deficit of 8.68% forms at a final orbit of 1.085 AU(third planet in No.6), and a planet with a final mass of 0.795 M⊕ and a core density deficit of 7.95% forms at a final orbit of 0.887 AU(second planet in No.12). -- astro-ph.EP

Exoplanets, -moons, -comets, Impact events, Lava / magma ocean / Volcanic Worlds, Status Report, Water/Hycean Worlds & Oceanography

Multiple Giant Impacts and Chemical Equilibria: An Integrated Approach to Rocky Planet Formation

by Keith CowingSeptember 26, 2025September 26, 2025

During the formation of rocky planets, the surface environments of growing protoplanets were dramatically different from those of present-day planets.

TOP: Other MUSE reductions showing the detection of AB Aur b from OB4. (left, middle) 6558.88 Aand 6560.13 Afrom the reduction shown in Figure 1. Average of the 6558.88 Aand 6560.13 Aslices from a classical SDI reduction (right). In each panel, we mask the field out to a separation affected by horizontal striping and saturation BOTTWO: Detection of AB Aur b from OB2 (left, middle panels) and weaker detection from OB1 in blue-shifted Hα (right). -- astro-ph.EP

Astronomy & Telescopes, Exploration Gear & Tech, Imaging & Spectroscopy, Status Report

VLT/MUSE Detection Of The AB Aurigae b Protoplanet With Ha Spectroscopy

by Keith CowingAugust 29, 2025

We analyze high-contrast, medium-spectral-resolution Hα observations of the star AB Aurigae using the Very Large Telescope’s Multi Unit Spectroscopic Explorer (MUSE).

Final size of protoplanets after 2 My of Hill regime pebble accretion, for different Stokes numbers of silicate and metal pebbles. The plot shows protoplanet mass relative to Earth (white contours and shading) and protoplanet metal mass fraction (black contours) as functions of the Stokes numbers of metal and silicate pebbles. The red dots represent chondrule and metal grain Stokes numbers based on measured size and density in the Kelly (K), Bjurbole (B), and Hammond Down (H) chondrites, respectively. The turquoise box indicates the implied range of pebble Stokes numbers, including individual metal grains and metal grain aggregates. The red contour corresponds to an Earth-like (Fe+Ni)/Si mass ratio of 2.06 and defines our preferred models with protoplanetary masses between 0.35 and 0.7 Earth masses. -- astro-ph.EP

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Status Report

Building Earth With Pebbles Made Of Chondritic Components

by Keith CowingJuly 23, 2025July 23, 2025

Pebble accretion provides new insights into Earth’s building blocks and early protoplanetary disk conditions.

The result of 100 successful simulations of the back20 model (the ring at 0.85 au with a 20% background) that produced a good match to all terrestrial planets (as defined in Section 3.1). The black dots show the results of individual simulations with good final planets. The bigger red dots are the real planets. Note that we do not exclude simulations that produced additional bodies with m < 0.05 MEarth in the Mars region (1.2 < a < 1.8 au). Some of these bodies would collide with Mars at t > 200 Myr (these simulations were terminated at 200 Myr). -- astro-ph.EP

Astrogeology, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Impact events, Status Report

Terrestrial Planet Formation From Two Source Reservoirs

by Keith CowingJuly 22, 2025July 22, 2025

This work describes new dynamical simulations of terrestrial planet formation. The simulations started at the protoplanetary disk stage, when planetesimals formed and accreted into protoplanets, and continued past the late […]

Substructures in protoplanetary disks, such as (a) spiral arms and (b) gaps, can inform the location and mass of protoplanets that shape these substructures (marked with arrows here; e.g., Dong & Fung 2017; Bae et al. 2018). Note: the panels displayed here use simulated data provided by Dong et al. (2015) for (a) and Bi & Lin (2024) for (b). -- astro-ph.IM

Astronomy & Telescopes, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Bathymetry, Status Report

Studying Protoplanets and Protoplanetary Disks with the Habitable Worlds Observatory

by Keith CowingJuly 3, 2025July 3, 2025

Since the discovery of the first exoplanet orbiting a Sun-like star, the confirmation of nearly 6000 exoplanets to date – and their diversity – has revolutionized our knowledge of planetary […]

MRS continuum-subtracted spectra of C2H2 (magenta), HCN (green), H2O (blue), and CO2 (brown) emission lines between 13.6-15.3 µm from JDISCS sources with sub-mm dust sizes r > 63 au. ALMA images are shown to the right of the spectra (Andrews et al. 2018; Long et al. 2018, 2019a, Long et al. 2025, in prep), in order of sub-mm dust disk size from largest (top left; Elias 27, r ∼ 250 au) to smallest (bottom right; RU Lup, r ∼ 63 au). Slab model fits to the molecular emission lines are overplotted on the spectra, corresponding to the best-fit parameters and upper limits reported in Tables 5, 6, 7, and A1. 13C 12CH2 emission is also detected in the spectrum of GO Tau, along with multiple CO2 isotopologues in MY Lup (Salyk et al. 2025), and an OH-rich spectrum with no CO2 emission from GM Aur (Romero-Mirza et al., submitted). -- astro-ph.SR

Astrochemistry, Astrogeology, Astronomy & Telescopes, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Interstellar, Status Report

The JDISC Survey: Linking the Physics and Chemistry of Inner and Outer Protoplanetary Disk Zones

by Keith CowingMay 13, 2025May 13, 2025

MIRI spectra of select targets from the JDISCS sample, representing broad categories of sources, namely: intermediate mass, transition disk (with a large dust cavity), solar-mass with weak water emission, solar-mass […]

The dominant phosphorous reservoirs throughout the HD 100546 disk. Left-hand panel: a map of the calculated disk temperature structure, which dictates phosphorous mineral stability. Normalised height above midplane is given by z/r, with height above midplane, z (au), divided by the radial distance, r (au). Hatched regions indicate the two dust rings identified in this system and the dotted black line marks the water iceline (parameterised simply as the 121 K isotherm after Lodders 2003). Right-hand panel: a map of the dominant phosphorous reservoirs in the disk assuming equilibrium at the dust temperature. The minerals apatite, merrillite, and schreibersite progressively replace each other as the main phoshporous reservoir as temperature is increased, up to the point where temperatures are high enough that all major phosphorous-bearing mineral phases have sublimated and most phosphorous is in the gas phase. Phosphorous dissolved in Fe metal is never a dominant reservoir, but its presence is mapped by the dashed contour. Mineral stabilties were taken from Pasek (2019). -- astro-ph.EP

Ariel Mission, Astrochemistry, Astrogeology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

Refractory Phosphorus In The HD 100546 Protoplanetary Disk

by Keith CowingApril 22, 2025April 22, 2025

The phosphorus budget of planets is intertwined with their formation history and is thought to influence their habitability.

Protoplanet

Rare Meteorite Provides Evidence Of A Giant Early Planet

Simulating The Interplay Between The Snowline Pebble Flux And Ongoing Planet Formation And Migration

Circumplanetary Disk Candidate In The Disk of HD 163296 Traced By Localized Emission From Simple Organics

Multiple Giant Impacts and Chemical Equilibria: An Integrated Approach to Rocky Planet Formation

VLT/MUSE Detection Of The AB Aurigae b Protoplanet With Ha Spectroscopy

Building Earth With Pebbles Made Of Chondritic Components

Terrestrial Planet Formation From Two Source Reservoirs

Studying Protoplanets and Protoplanetary Disks with the Habitable Worlds Observatory

The JDISC Survey: Linking the Physics and Chemistry of Inner and Outer Protoplanetary Disk Zones

Refractory Phosphorus In The HD 100546 Protoplanetary Disk

NASA Spaceline Current Awareness List #1,208 17 July 2026 (Space Life Science Research Results)

Tidal Evolution Of Packed Moon Systems Around An Earth-mass Planet

Deep-sea Creatures’ Epic Migrations Between Hydrothermal Vents

Efficient Interstellar Grain Growth From High Sticking Coefficients On Amorphous Carbon Dust

A Pressure-Supported Pneumatic Architecture for Robust Deep Drilling on Mars: Performance Modeling, Sizing, and Mission Integration.