Effective temperatures, surface gravities, and iron abundances were derived for 109 stars observed by the K2 mission using equivalent width measurements of Fe I and Fe II lines. Calculations were […]
Spectroscopy
Posted inAstrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Mars, Status Report, Water/Hycean Worlds & Oceanography
Observations of Water Frost on Mars with THEMIS: Application to the Presence of Brines and the Stability of (Sub)Surface Water Ice
Characterizing the exchange of water between the Martian atmosphere and the (sub)surface is a major challenge for understanding the mechanisms that regulate the water cycle.
![Analysis of the stellar parameters derived with our methodology. The dots are colour-coded according to the estimated metallicity. The size of the dots is proportional to the estimated projected rotational velocity. The top left panel shows a Kiel diagram, with the red, black, and blue dashed lines corresponding to 5 Gyr PARSEC isochrones with [M/H] = −0.4, 0.0 and 0.1 dex, respectively. Empty squares represent the stars reported to have a behaviour akin to subdwarfs both in Mar21 and Schw19 (same for bottom left panel). Top right: black and grey dashed lines correspond to solar metallicity PARSEC isochrones for 5 and 0.1 Gyr, respectively. Black and grey dotted lines correspond to solar metallicity Baraffe et al. (2015) isochrones for 5 and 0.1 Gyr, respectively. Bottom left: triangles represent stars identified as Hα active in Schöfer et al. (2019). Empty stars depict members of the thick disc Galactic population (Cortés-Contreras et al., in prep.). Bottom right: plus symbols correspond to stars identified as members of the young disc Galactic population by Cortés-Contreras et al. (in prep.). Empty circles represent stars with a possible membership in a young stellar associaton, as explained in Section 4.1. -- astro-ph.SR](https://i0.wp.com/astrobiology.com/wp-content/uploads/2024/05/Using-Autoencoders-And-Deep.png?resize=1200%2C717&ssl=1)
Posted inAI - Data - Apps - Cybernetics, Astronomy & Telescopes, Imaging & Spectroscopy, Status Report, Stellar Cartography
Using Autoencoders And Deep Transfer Learning To Determine The Stellar Parameters Of 286 CARMENES M Dwarfs
Deep learning (DL) techniques are a promising approach among the set of methods used in the ever-challenging determination of stellar parameters in M dwarfs.
Posted inAstronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report
Exoplanet Transit Spectroscopy with JWST NIRSpec: Diagnostics and Homogeneous Case Study of WASP-39 b
The JWST has ushered in a new era of exoplanet transit spectroscopy. Among the JWST instruments, the Near-Infrared Spectrograph (NIRSpec) has the most extensive set of configurations for exoplanet time […]
Posted inAstrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Enceladus, Icy Worlds, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography
Constraining Time Variations in Enceladus’ Water-Vapor Plume With Near-Infrared Spectra from Cassini-VIMS
Water vapor produces a series of diagnostic emission lines in the near infrared between 2.60 and 2.75 microns. The Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft detected […]
Posted inAstrochemistry, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Status Report
Formation of N-bearing Complex Organic Molecules in Molecular Clouds: Ketenimine, Acetonitrile, Acetaldimine, and Vinylamine via the UV Photolysis of C2H2 Ice
The solid-state C2H2 chemistry in interstellar H2O-rich ice has been proposed to explain astronomically observed complex organic molecules (COMs), including ketene (CH2CO), acetaldehyde (CH3CHO), and ethanol (CH3CH2OH), toward early star-forming […]
![[L] The planet radius histogram showing the radius gap at ∼1.8 Earth radii. The blue and red lines are kernel density estimations of the smoothed underlying distribution and identify the location of the radius separating the two planet populations (∼ 1.8), and the peaks of the two planet populations at 1.5 and 2.4 Earth radii. -- astro-ph.SR [R] The XUV flux received by planets compared to their gravitational potential in order to determine the possible atmospheric escape process following the method in Salz et al. (2016). The rapid hydrodynamical escape process applies to the left of the red dashed line. Slower, Jeans escape applies to the right of the blue solid line. Markers are crosses for planets above the radius gap and circles for planets below the radius gap. -- astro-ph.SR](https://i0.wp.com/astrobiology.com/wp-content/uploads/2024/05/ExoplANETS-A.png?resize=1200%2C712&ssl=1)
Posted inAI - Data - Apps - Cybernetics, Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Press Release, Stellar Cartography
ExoplANETS-A: A VO Database For Host Stars And Planetary Systems: The Effect Of XUV On Planet Atmospheres
ExoplANETS-A is an EU Horizon-2020 project with the primary objective of establishing new knowledge on exoplanet atmospheres. Intimately related to this topic is the study of the host-stars radiative properties […]
Posted inAstronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report
Three Short-period Earth-sized Planets Around M dwarfs Discovered By TESS: TOI-5720b, TOI-6008b And TOI-6086b
One of the main goals of the NASA’s TESS (Transiting Exoplanet Survey Satellite) mission is the discovery of Earth-like planets around nearby M-dwarf stars.
Posted inAstrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Press Release
A Molecular Production Line Inside a Busy Star Factory in a Starburst Galaxy
An international research team led by Sergio Martín of the European Southern Observatory/Joint ALMA Observatory, Nanase Harada of the National Astronomical Observatory of Japan, and Jeff Mangum of the National […]
![Cumulative XUV irradiation vs. planetary escape velocity for a range of rocky exoplanets (grey squares and colored circles) and solar system planets (blue stars). The cumulative lifetime XUV is thought to be the driving force behind planetary evaporation. Atmospheres can be found where gravity is high and solar irradiation is low. The light blue colored line represents the proposed “cosmic shoreline” which follows a power law, IXUV ∝ vesc4 , following [15]. Rocky planets around M dwarfs can be studied with JWST to assess the validity of this shoreline. Plot adapted from [16]. -- astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2024/05/Characterizing-Exoplanetary-Atmospheres.png?resize=1200%2C725&ssl=1)
Posted inAstrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report
Characterizing Exoplanetary Atmospheres: New Views on Exoplanet Composition and Chemistry
I review the major open science questions in exoplanet atmospheres. These are mainly focused in the areas of understanding atmospheric physics, the atmosphere as a window into other realms of […]