![Final semi-major axes and masses for all objects produced in simulations with regular disks. The left panel shows objects produced in disks with low C/O ratios and the right one shows planets in high C/O ratio disks. The dash-dotted line shows the initial mass of planestesimals in our simulations while the dotted line shows the initial mass of planetary embryos. We consider planets to be anything at or above the initial embryo mass, fragments to be anything below the initial planetesimal mass, and planetesimals to be any object at or above the initial planetesimal mass but below the initial embryo mass. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Correlations.png?resize=1200%2C719&ssl=1)
[astro-ph.EP] Studies suggest that protoplanetary disks around stars with high carbon-to-oxygen (C/O) ratios can produce terrestrial planets with carbon-dominated compositions instead of silicon-dominated ones.
astrochemistry
![Chemical clock relations for planet-hosting solar analogs, showing abundance ratios as a function of stellar age for [Y/Mg], [Y/Al], [Ba/Mg], [Ba/Al], [Sr/Mg], and [Y/(Mg+Al)/2]. Data points are color-coded by metallicity ([Fe/H]). Black lines show best-fit linear relations derived using Deming regression, accounting for uncertainties in both variables, and shaded regions indicate 1σ confidence intervals. All abundance ratios show statistically significant correlations with stellar age. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Planets-Around.png?resize=1200%2C720&ssl=1)
Posted inExoplanets, -moons, -comets
Planets Around Solar Twins/Analogs (PASTA) III: Chemical Clock Relations in Planet-Hosting Solar Analogs
[astro-ph.EP] Context. Abundance ratios between elements synthesized on different nucleosynthetic timescales provide empirical chemical clocks for estimating stellar ages, but robust calibrations require homogeneous samples with precise stellar parameters and […]
![Infrared spectra of pure H2S (blue) and H2O:H2S (10:1) (red) ice mixtures after UV irradiation followed by warm-up to room temperature, measured at 300 K. The residue from the H2S ice does not show any IR absorption band. Functional groups assigned to bands in the H2O:H2S (10:1) residue are indicated at the top; vibrational bands and assignments are also listed in Table 1, along with possible carrier species or chemical families producing those features. -- [astro-ph.GA]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Water-.png?resize=1200%2C720&ssl=1)
Posted inAstrochemistry
Water Enhances The Formation Of Refractory Sulfur In Interstellar Ices
[astro-ph.GA] Sulfur is the tenth most abundant element in space, yet it is strongly depleted in the gas phase of dense interstellar regions, suggesting sequestration in dust grain components that […]
Posted inAstrochemistry
Chemical Diversity Of Dense Cores In Orion B: The Role Of The Environment
[Astronomy & Astrophysics] Context. Pre-stellar cores are the sites of the earliest stages of star formation. Dust continuum observations are often used to identify and characterise their properties yet only […]
![Rest-frame equivalent widths of C iii] 𝜆𝜆1907, 1909 (left) and C iv 𝜆𝜆1548, 1550 (right) against the direct 𝑇e-based ([O III]𝜆4363) metallicity. Curves are the star-forming photoionisation grids of Nakajima et al. (2018) at a burst age of 1 Myr and log(𝑛H/cm−3 ) = 3. Solid curves represent the POPSTAR single-star models (Mollá et al. 2009), and dashed curves indicate the BPASS binary models (Eldridge et al. 2017), coloured by ionisation parameter as shown in the colour-bar. -- [astro-ph.GA]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Precise.png?resize=1200%2C720&ssl=1)
Posted inAstrochemistry
Precise C-N-O Abundances of Individual Galaxies In The First Billion Years From Ultra-Deep, Rest-UV-to-Optical JWST Spectroscopy
[astro-ph.GA] We present ultra-deep JWST/NIRSpec 𝑅 ∼ 1000 spectroscopy of nine star-forming galaxies at 𝑧 = 6.0 − 8.3 in the GOODSN field, drawn from the Origins of Metal Enrichment […]
Posted inAstrochemistry
Secondary Ion-Ice Chemistry in UV-Irradiated Oxygen Ice: New Astrochemical Models Including Bulk Ionic Species
[ACS Earth Space Chemistry] Although energetic and nonenergetic processing of interstellar dust grain surfaces and ice is thought to be one of the dominant mechanisms for the extraterrestrial synthesis of […]
![Visual abstract -- [Journal of the American Chemical Society]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Nonequilibrium.jpg?resize=1200%2C716&ssl=1)
Posted inAstrochemistry
Nonequilibrium Formation of Pyridine (C5H5N) in Interstellar Ice Analogs: Implications for Biorelevant Nitrogen Heterocycles in Ryugu and Bennu
[Journal of the American Chemical Society] Biorelevant nitrogen heterocycles, including the five canonical nucleobases found in RNA and DNA, have recently been identified in samples returned from the carbonaceous asteroids […]
Posted inAstrochemistry
The Abundance And Emission Of PAHs From The Local To Early Universe
[astro-ph.GA] We present the first large-volume cosmological simulation of galaxy evolution with a model for the abundance and luminous emission of Polycyclic Aromatic Hydrocarbons (PAHs) across a wide range of […]
Posted inAstrogeology
Our Solar System Chose Fire Over Ice To Build Its First Bodies
[Yale University] When the solar system first took up the task of building solid bodies — such as planets, moons, and protoplanets — it basically had a choice between two […]
Posted inAstrochemistry
Modeling The Radiolysis In H2O:HCOOH ice: Connecting Laboratory Experiments With Astronomical Measurements
[RSC Advances] We present a computational study of radiolytic chemistry and desorption dynamics in astrophysical ice composed of H2O:HCOOH (1 : 1), irradiated with Ni11+ ions at 46 MeV and […]