The carbonaceous macromolecules imprinting in astronomical spectra the numerous absorptions called Diffuse Interstellar Bands (DIBs) are omnipresent in the Galaxy and beyond and represent a considerable reservoir of organic matter.
Spectroscopy
![The [Fe/H] versus C/O distribution for this work sample, as well as other M dwarfs studied by Souto et al. (2017), Souto et al. (2018), Souto et al. (2020). The orange circles represent the results for the four JWST targets studied here; Results for M dwarfs from our previous studies (all based on the same methodology as here) are also shown: orange triangles are M dwarfs with exoplanets detected, while the gray squares are M dwarfs without exoplanets detected so far. We also present results for FGK dwarfs from Nissen (2013) (green triangles; all with detected exoplanets), Teske et al. (2014) with (light blue diamonds) detected exoplanets, and Delgado Mena et al. (2021) with (pink circles), and without detected exoplanets (yellow cross). Additionally, four curves represent the linear regressions of the [Fe/H] vs. C/O distribution for M dwarfs with planet detected (solid orange line), M dwarfs without planet detected (solid gray line), FGK dwarfs with detected planets (dashed orange line), and FGK dwarfs without detected planets (dashed gray line). -- astro-ph.SR](https://i0.wp.com/astrobiology.com/wp-content/uploads/2024/06/Stellar-Characterization-and.png?resize=1200%2C719&ssl=1)
Posted inAstrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, Stellar Cartography, Water/Hycean Worlds & Oceanography
Stellar Characterization and Chemical Abundances of Exoplanet Hosting M dwarfs from APOGEE Spectra: Future JWST Targets
Exoplanets hosting M dwarfs are the best targets to characterize Earth-like or super-Earth planetary atmospheres with the James Webb Space Telescope (JWST). We determine detailed stellar parameters (Teff, logg, and […]
Posted inAstrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Status Report
The High-Resolution Far- to Near-Infrared Anharmonic Absorption Spectra of Cyano-Substituted Polycyclic Aromatic Hydrocarbons from 300-6200 cm−1
Cyano-substituted polycyclic aromatic hydrocarbons (CN-PAHs) may contribute to the emission detected in the 7 – 9 μm (1430 – 1100 cm−1) and 11 – 15 μm (900 – 670 cm−1) […]
Posted inAstronomy & Telescopes, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, Stellar Cartography
HST SHEL: Enabling Comparative Exoplanetology with HST/STIS
The Hubble Space Telescope (HST) has been our most prolific tool to study exoplanet atmospheres. As the age of JWST begins, there is a wealth of HST archival data that […]
![Left: An example of PSF matching between the [O III] λ5007 PNB image from Keck/KCWI (top-left) and the [O III] 88 µm PNB image from Herschel/PACS (bottom-left). The KCWI PNB image has been convolved with a 2D Gaussian kernel (top-right) to match the PACS PNB image’s PSF. The resulting residual is shown in the bottom-right panel. The red dashed circles indicate the apertures from which the 1D spectra were extracted. Right: Modeling of dust attenuation based on the observed flux ratios of hydrogen Balmer and Paschen lines. In the top panel, the data points represent the correction factors needed to align the observed flux ratios with those predicted by Case B recombination. The best-fit attenuation models are represented by solid curves, while the shaded areas denote their 1σ uncertainties. The blue (orange) color indicates the 1D spectra before (after) PSF matching. The steep slope at the lower wavelengths is primarily due to contributions from stellar absorption. The lower panel shows the fractional deviations between the observed and best-fit flux ratios, for the same data points. Data points near unity indicate a good agreement with the attenuation model. -- astro-ph.GA](https://i0.wp.com/astrobiology.com/wp-content/uploads/2024/06/Robust-Nitrogen-and-Oxygen.png?resize=1200%2C717&ssl=1)
Posted inAstrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Status Report
Robust Nitrogen and Oxygen Abundances of Haro 3 from Optical and Infrared Emission
Accurate chemical compositions of star-forming regions are a critical diagnostic tool to characterize the star formation history and gas flows which regulate galaxy formation.
Posted inAstrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gas Giants, Icy Worlds, Imaging & Spectroscopy, Status Report
Recipes For Forming A Carbon-rich Giant Planet
The exploration of carbon-to-oxygen ratios has yielded intriguing insights into the composition of close-in giant exoplanets, giving rise to a distinct classification: carbon-rich planets, characterized by a carbon-to-oxygen ratio ≥ […]
![Left: C/O as a function of projected separation or semi-major axis for the eight companions in this study. The points are sized by companion mass, using the mass legend in the right panel. The blue line and region show the solar C/O value from Asplund et al. (2021). Right: In color: 1σ contours of C/O and [C/H] for the eight companions, which are all consistent with solar composition (intersection of dashed gray lines) to the 2σ level. In § 6.4.1, we justify that their host stars likely have solar composition as well. We overplot hot Jupiters which have abundance measurements for at least one oxygen-bearing and one carbon-bearing species from JWST or high-resolution spectroscopy as black points (Alderson et al. 2023; August et al. 2023; Bean et al. 2023; Bell et al. 2023; Brogi et al. 2023; Finnerty et al. 2024; Xue et al. 2024), which are also sized by mass. The hot Jupiters show considerable scatter and super-solar (and super-stellar) metallicities except for one planet, unlike our companions which cluster around solar (and stellar) composition. -- astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2024/06/Are-These-Planets.png?resize=1200%2C719&ssl=1)
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Brown Dwarfs, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Stellar Cartography
Are These Planets Or Brown Dwarfs?
Using Keck Planet Imager and Characterizer (KPIC) high-resolution (R~35000) spectroscopy from 2.29-2.49 μm, we present uniform atmospheric retrievals for eight young substellar companions with masses of ~10-30 MJup, orbital separations […]
Posted inAstrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Status Report
Enhanced Formation Of Interstellar Complex Organic Molecules On Carbon Monoxide Ice
We investigate the role of carbon monoxide ice in the chemical evolution of prestellar cores using astrochemical rate equation models.
Posted inEuropa, Ganymede, Icy Worlds, Jupiter, Mapping, Geodesy, Cartography, Bathymetry, Missions & Hardware, Status Report, Water/Hycean Worlds & Oceanography
Calibration of MAJIS (Moons And Jupiter Imaging Spectrometer): III. Spectral Calibration
The Moons And Jupiter Imaging Spectrometer (MAJIS) is the visible and near-infrared imaging spectrometer onboard ESA’s Jupiter Icy Moons Explorer (JUICE) mission.
Posted inAtmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report
Exoplanet Aeronomy: A Case Study of WASP-69b’s Variable Thermosphere
Aeronomy, the study of Earth’s upper atmosphere and its interaction with the local space environment, has long traced changes in the thermospheres of Earth and other solar system planets to […]