![(a) Top panel shows [Eu/α] independent of the temperature bias as a function of [α/H]. Small orange triangles represent data from DM and small green triangles represent data from BB. The cross matched sample of 68 stars described in Section 3.1 is shown in big red squares. Stars from the solar twins analysis by Spina et al. (2018), Bedell et al. (2018) are shown as big blue circles. A black star is used to represent the solar abundance value. The red dashed line at [Eu/α] = 0.06 represents the critical value for an extended dynamo failure given by the model from Nimmo et al. (2020). Outliers in [Eu/H] abundances discussed in Section 6.2 are outlined in black. -- astro-ph.SR](https://i0.wp.com/astrobiology.com/wp-content/uploads/2025/10/Distribution-of-Europium.png?resize=1200%2C711&ssl=1)
The energy provided in the radioactive decay of thorium (Th) and uranium (U) isotopes, embedded in planetary mantles, sustains geodynamics important for surface habitability such as the generation of a […]
metallicity
Posted inAstrochemistry, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Space Weather & Heliophysics, Status Report
Modelling The Effect Of Stellar Metallicity On The XUV Evolution Of Low-mass Stars and its Impact on Exoplanet Atmospheres/habitability
Understanding how exoplanet atmospheres evolve is a key question in the context of habitability. One key process governing this evolution is atmospheric evaporation by stellar X-ray and EUV emission (collectively, […]
Posted inAstrobiology (general), Astrochemistry, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biophysics, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Status Report
Transition Metal Abundance As A Key Parameter For The Search Of Life In The Universe
The search for Life in the Universe generally assumes three basic life’s needs: I) building block elements (i.e., CHNOPS), II) a solvent to life’s reactions (generally, liquid water) and III) […]
![PAH fraction anti-correlates with log([S iii]/[S ii]) (ionization parameter tracer) for thousands H ii regions in 42 PHANGS-JWST galaxies. Panel (a, b) shows all ∼ 17200 analyzed H ii regions, while ∼ 5600 brightest “resolved” H ii regions are shown on Panels (c, d). The dashed red line shows the best-fit linear regression to the “resolved” sample defined by Eq. 4. Histograms on panels (b, d) show how the logarithmic residuals after subtracting this linear trend depend on metallicity. Color on panels (a, c) denotes gas-phase oxygen abundance; red contours show the probability density of the high-metallicity (12 + log(O/H) > 8.2) points (levels correspond to 50, 65, 80, 95 and 99 percentile intervals). The Spearman correlation coefficient (ρ) and RMS scatter around the linear fit are reported on panels (a, c). -- astro-ph.GA](https://i0.wp.com/astrobiology.com/wp-content/uploads/2025/09/Polycyclic-aromatic-hydrocarbons-destruction.png?resize=1200%2C720&ssl=1)
Posted inAstrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Status Report
Polycyclic Aromatic Hydrocarbons Destruction In Star-forming Regions Across 42 Nearby Galaxies
Polycyclic aromatic hydrocarbons (PAHs) are widespread in the interstellar medium (ISM) of Solar metallicity galaxies, where they play a critical role in ISM heating, cooling, and reprocessing stellar radiation.
Posted inAstrochemistry, Astrogeology, Astropharmacy / Biotechnology, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Origin & Evolution of Life, Status Report
Stellar Metallicity Is A Key Parameter For The Search Of Life In The Universe
The search for Life in the Universe generally assumes three basic life’s needs: I) building block elements (i.e., CHNOPS), II) a solvent to life’s reactions (generally, liquid water) and III) […]
![Results of the pRT retrievals for the atmosphere of HD 86226 c. Left: PACMAN spectrum (black data) and 1, 2, and 3σ percentiles of the spectra from the posteriors of the pRT retrieval with scaled solar chemistry (green shadings). The gray spectra show cloud-free models with 1× and 1000× solar metallicity. Right: Posterior distribution for the two retrieval runs with scaled solar chemistry (green) and H-He-H2O atmosphere (purple). The pressures are provided in units of log10([bar]). Contours are drawn at the 1, 2, and 3σ levels. Vertical dashed lines mark the 16%, 50%, and 84% quantiles. astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2025/07/The-SPACE-Program-I.png?resize=1200%2C709&ssl=1)
Posted inAtmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report
The SPACE Program I: The Featureless Spectrum Of HD 86226 c Challenges Sub-Neptune Atmosphere Trends
Sub-Neptune exoplanets are the most abundant type of planet known today. As they do not have a Solar System counterpart, many open questions exist about their composition and formation.
Posted inAstrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Status Report
Metallic Species In Interstellar Medium: Astrochemical modeling
Metal-bearing species in diffuse or molecular clouds are often overlooked in astrochemical modeling except for the charge exchange process.
Posted inAstronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Press Release, Space Weather & Heliophysics
Gravity-sensitive Spectral Indices In Ultracool Dwarfs: Investigating Correlations With Metallicity And Planet Occurrence Using SpeX and FIRE Observations
We present a near-infrared spectroscopic analysis (0.9-2.4 micron) of gravity indices for 57 ultracool dwarfs (spectral types M5.5 to L0), including exoplanet hosts TRAPPIST-1, SPECULOOS-2, SPECULOOS-3, and LHS 3154. Our […]
Posted inAtmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Status Report
The Mutual Influence of Disequilibrium Composition and Temperature in Exoplanet Atmospheres
We have developed a 1D planetary atmosphere model that solves in a self-consistent manner the evolution of temperature and disequilibrium chemistry in the vertical direction.
Posted inAstrochemistry, Astrogeology, Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Space Weather & Heliophysics, Status Report, Stellar Cartography
Revisiting The Li Abundances Of Stars With And Without Detected Planets From The High Resolution Spectroscopy
Whether the presence of planets affects the lithium (Li) abundance of their host stars is still an open question.