Protoplanetary Disk Archives - Page 23 of 27 - Astrobiology

The example of trajectories of particles which are initially located in the midplane at 80 au from the central star. The trajectories were tracked for 106 yr. The trajectories of the particles with the size of 1, 10, 100, and 1000 𝜇m are shown in yellow, red, blue, and green, respectively. -- astro-ph.GA

Astrochemistry, Astrogeology, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Status Report

Chemical Evolution of Complex Organic Molecules in Turbulent Protoplanetary Disks: Effect of stochastic UV irradiation

by Keith CowingJune 26, 2024June 26, 2024

We investigate the chemical evolution of complex organic molecules (COMs) in turbulent disks using gas-ice chemical reaction network simulations.

High resolution ALMA images of Elias 24 at 1.3 mm and 3 mm, with an RMS of 0.35 K (19 µJy beam−1 ) at 1.3 mm and 0.33 K (9 µJy beam−1 ) at 3 mm. The white ellipse in the bottom left shows the beam size of the image, corresponding to 0.036′′ × 0.034′′ (5.0 au × 4.7 au) at 1.3mm, 0.060′′ × 0.058′′ (8.2 au × 7.9 au) at 3mm. The white hash at the bottom right is 10 au. -- astro-ph.EP

Astrogeology, Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

A Dust-Trapping Ring in the Planet-Hosting Disk of Elias 2-24

by Keith CowingJune 22, 2024

Rings and gaps are among the most widely observed forms of substructure in protoplanetary disks.

Two scenarios to produce a high C/O ratio in the inner disk. Schematic cross-sections of the disk around a VLMS in the (A) oxygen depletion and (B) carbon enrichment scenarios. The left sides of each panel illustrate the C/O enrichment process, while the right sides show the resulting state of the disk, corresponding to when we observe it. Colored shading indicates elemental abundances of carbon (orange) and oxygen (blue). The two-color arrows pointing towards the VLMS indicate accretion of material onto the star. The grey arrow indicates transport processes. The region between the two vertical dotted lines indicates the region where the carbon in the solids is released into the gas. The brown, blue, and grey blobs indicate unaffected solids, ice covered solids and carbon depleted solids in the disk respectively. -- astro-ph.EP

Astrochemistry, Astrogeology, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Status Report

Abundant Hydrocarbons in the Disk Around a Very-low-mass Star

by Keith CowingJune 21, 2024June 21, 2024

Very low-mass stars (those <0.3 solar masses) host orbiting terrestrial planets more frequently than other types of stars, but the compositions of those planets are largely unknown.

In this image of the Serpens Nebula from NASA’s James Webb Space Telescope, astronomers found a grouping of aligned protostellar outflows within one small region (the top left corner). Serpens is a reflection nebula, which means it’s a cloud of gas and dust that does not create its own light, but instead shines by reflecting the light from stars close to or within the nebula. NASA, ESA, CSA, K. Pontoppidan (NASA’s Jet Propulsion Laboratory) and J. Green (Space Telescope Science Institute).

Astrochemistry, Astronomy & Telescopes, Imaging & Spectroscopy, Interstellar, Press Release

Astrochemistry Update: First of Its Kind Detection Made in Striking New Webb Image

by Keith CowingJune 21, 2024June 21, 2024

For the first time, a phenomenon astronomers have long hoped to directly image has been captured by NASA’s James Webb Space Telescope’s Near-Infrared Camera (NIRCam). In this stunning image of […]

Optical image of the clastic matrix region in LAR 12252 that was studied using S-XANES. Notable phases include enstatite (example outlined in red), sulphides (example outlined in yellow), a small chondrule fragment (outlined in orange), and fine matrix (example highlighted in pink). b Corresponding map calculated from the SXANES spectra of the region shown in a, showing the amplitude of the H-S peak at each point normalised to the average amplitude of point spectra measured from chondrule mesostasis. Black pixels correspond to points where the S-XANES spectra that did not contain a resolvable H-S peak. White pixels correspond to points where the SXANES spectra could not be fitted due to their quality or noise in the spectra. -- astro-ph.EP

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Comets and Asteroids, Meteorites & Asteroids, Status Report, Water/Hycean Worlds & Oceanography

The Source of Hydrogen in Earth’s Building Blocks

by Keith CowingJune 21, 2024June 21, 2024

Despite being pivotal to the habitability of our planet, the process by which Earth gained its present-day hydrogen budget is unclear. Due to their isotopic similarity to terrestrial rocks across […]

Reprocessed images of Uranus [L]] and Neptune [R] NASA/JPL-Caltech (Uranus and Neptune); “Modelling the Seasonal Cycle of Uranus’s Colour and Magnitude, and Comparison with Neptune,” by Patrick G. J. Irwin et al., in Monthly Notices of the Royal Astronomical Society, Vol. 527, No. 4; February 2024 (reprocessed images)

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Gas Giants, Ice Giant, Icy Worlds, Neptune, Status Report, Uranus

Insights on the Formation Conditions of Uranus and Neptune from their Deep Elemental Compositions

by Keith CowingJune 20, 2024May 12, 2025

This study, placed in the context of the preparation for the Uranus Orbiter Probe mission, aims to predict the bulk volatile compositions of Uranus and Neptune. Using a protoplanetary disk […]

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Status Report

Investigating Sulfur Chemistry In The HD 163296 Disk

by Keith CowingJune 16, 2024June 13, 2024

Sulfur chemistry in the formation process of low-mass stars and planets remains poorly understood. The protoplanetary disks (PPDs) are the birthplace of planets and its distinctive environment provides an intriguing […]

Cartoon of the planetary envelope in different scenarios, each featuring one volatile species (in blue) and one refractory species (in brown). The infalling pebbles are shown on the left side of the envelope. Initially, they consist of a refractory core (brown dot) and an icy volatile layer (blue ring). On the right side, we show the recycling flows (in magenta) and the dust grains (blue dots) that they carry away. The envelope temperature increases overall from A to D. A: Cold envelope in which the volatile sublimation temperature is not reached. B: The volatile species evaporates in the envelope (indicated by the blue arrows), but the recycling flows do not reach deep enough to prevent the accretion of the volatile. Latent heat is absorbed during the evaporation of the volatile ice (indicated by the red arrows). C: The volatile species evaporates in the envelope and the recycling flows transport the vapor back beyond the volatile evaporation front, where the volatile recondenses onto the dust grains. The dust grains covered in ice are then recycled back into the disk. There is no net latent heat absorption due to the recondensation subsequent to the evaporation. D: Same as C, but the envelope is hot enough to vaporize the refractory species, causing the absorption of latent heat in the process. The refractory vapor is not recycled. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Status Report, TRAPPIST-1, Water/Hycean Worlds & Oceanography

A Formation Pathway For Terrestrial Planets With Moderate Water Content Involving Atmospheric-volatile Recycling

by Keith CowingJune 14, 2024June 14, 2024

Of the many recently discovered terrestrial exoplanets, some are expected to harbor moderate water mass fractions of a few percent. The formation pathways that can produce planets with these water […]

Confirmed exoplanets around stars with masses 0.08

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

Rocky Planet Formation In Compact Disks Around M Dwarfs

by Keith CowingJune 13, 2024

Rocky planets in compact configurations are the most common ones around M dwarfs. Many disks around very low mass stars (between 0.1 and 0.5 M⊙) are rather compact and small […]

Comparisons between the theoretical transmission spectra generated by EPACRIS (solid lines) and the JWST observations for (Top) H2:H2O=50:50 and [C+N+S]=100×solar metallicity scenario of K2-18 b assuming Ab = 0.3 corresponding to the left panel of Figure 4, and (Bottom) H2:H2O=75:25 and [C+N+S]=100×solar metallicity scenario of TOI-270 d assuming Ab = 0 corresponding to the right panel of Figure 4. The grey symbols with error bars indicate JWST observations of corresponding exoplanets taken from Madhusudhan et al. (2023) for K2-18 b (Top), and Benneke et al. (2024) for TOI-270 d (Bottom). Each color represents a spectrum generated by excluding specific species: green for no CH4, red for no CO2, light blue for no OCS, blue for no H2O, teal for no CO, light brown for no NH3, and black for all species included. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Chemical Mapping of Temperate Sub-Neptune Atmospheres: Constraining The Deep-interior H2O/H2 Using The Atmospheric CO2/CH4

by Keith CowingJune 7, 2024June 7, 2024

Understanding the envelope composition of sub-Neptune-type exoplanets is challenging due to the inherent degeneracy in their interior composition scenarios. Particularly, the H2O/H2 ratio, or can be expressed as the O/H […]