Protoplanet – My WordPress Site

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

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

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 with planet-disc interaction models.

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, Water/Hycean Worlds & Oceanography

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

by Keith CowingSeptember 26, 2025September 26, 2025

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

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

by Keith CowingAugust 29, 2025

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

Building Earth With Pebbles Made Of Chondritic Components

by Keith CowingJuly 23, 2025July 23, 2025

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

Terrestrial Planet Formation From Two Source Reservoirs

by Keith CowingJuly 22, 2025July 22, 2025

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

Studying Protoplanets and Protoplanetary Disks with the Habitable Worlds Observatory

by Keith CowingJuly 3, 2025July 3, 2025

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

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

by Keith CowingMay 13, 2025May 13, 2025

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

Refractory Phosphorus In The HD 100546 Protoplanetary Disk

by Keith CowingApril 22, 2025April 22, 2025

Primary-subtracted images of PDS 70 in 2020 (left) and 2024 (right). North is up and East is to the left. Color scales of the two panels are identical. The expected positions of PDS 70 b and c are marked. The white dashed line marks the inner edge of PDS 70’s outer disk in infrared scattered light. PDS 70 b is detected in both epochs and demonstrates a significant orbital motion. PDS 70 c is only detected in Epoch 2024. The apparent brightness variations in PDS 70 b and c do not accurately represent the planets’ intrinsic variability, as high-contrast imaging post-processing introduces flux loss. For a comprehensive analysis of the evidence for variability, refer to Section 3.3. astro-ph.EP

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

Evidence for Variable Accretion Onto PDS 70 c and Implications for Protoplanet Detections

by Keith CowingFebruary 21, 2025

Astrochemistry, Astrogeology, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy

PDS 70b Shows Stellar-like Carbon-to-Oxygen Ratio

by Keith CowingNovember 25, 2024November 25, 2024