habitability Archives

Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

Paths To Robust Exoplanet Science Yield Margin For The Habitable Worlds Observatory

by Keith CowingMay 31, 2024May 31, 2024

The Habitable Worlds Observatory (HWO) will seek to detect and characterize potentially Earth-like planets around other stars. To ensure that the mission achieves the Astro2020 Decadal’s recommended goal of 25 […]

The surface temperature is displayed for the four PCb simulations used in this work: PCb PI (top left), PCb 10% PAL (top right), PCb 1% PAL (bottom left), PCb 0.1% PAL (bottom right). White arrows indicate the magnitude and direction of the surface winds. The magenta contours show surface temperatures of 273 K. For scale, a 10 m s-1 arrow is shown in the middle of the figure. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Proxima Centauri, Space Weather & Heliophysics, Status Report, TRAPPIST-1

Lethal Surface Ozone Concentrations Are Possible On Habitable Zone Exoplanets

by Keith CowingMay 31, 2024

Ozone (O3) is important for the survival of life on Earth because it shields the surface from ionising ultraviolet (UV) radiation. However, the existence of O3 in Earth’s atmosphere is […]

Garden cress (Lepidium sativum) grown on a sand substrate with one hundred initial seeds under solar (effective temperature 5800 K), K dwarf (effective temperature 4300 K) and dark conditions. Here the visual results for selected days are shown. Garden cress under K dwarf radiation sprouts sooner relative to solar and dark conditions. -- astro-ph.EP

Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Life Support Systems, Microbiology & Virology, Plant Biology, Space Agriculture, Space Weather & Heliophysics, Status Report, Terraforming & Geoengineering, Water/Hycean Worlds & Oceanography

Observation of Significant Photosynthesis in Garden Cress and Cyanobacteria under Simulated Illumination from a K Dwarf Star

by Keith CowingMay 30, 2024

Stars with about 45 to 80% the mass of the Sun, so-called K dwarf stars, have previously been proposed as optimal host stars in the search for habitable extrasolar worlds.

Sketch of the magnetospheric interaction in the starplanet system Proxima - Proxima b. The stellar wind velocity and the interplanetary magnetic field (IMF) streamlines (assumed to be radial–see text in Sect. 3) are drawn in green and red, respectively. Note that there are magnetic field lines from the star (yellow circle) that are connected to the exoplanet Proxima b (purple circle). The density distribution is shown as a color scale, normalized to the value of the stellar wind density, ρsw = µmpnsw (see Table 1). The sketch represents a super-Alfvénic case, where the ram pressure of the wind dominates over the stellar wind magnetic field pressure, so a bow shock is formed at the dayside of the planet. The Proxima star is beyond the limits of our simulation domain. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biophysics, Exoplanets, -moons, -comets, Habitable Zones, Magnetic Fields, Electromagnetism, bioelectricity,, Proxima Centauri, Radiation, Space Weather & Heliophysics, Status Report

MHD Simulations of the Space Weather in Proxima b: Habitability Conditions and Radio Emission

by Keith CowingMay 30, 2024May 30, 2024

The habitability of exoplanets hosted by M-dwarf stars dramatically depends on their space weather. We present 3D magneto-hydrodynamic simulations to characterise the magneto-plasma environment and thus the habitability of the […]

TOP: Same as Fig 6 but for the HARPS-N solar spectral time series with the HD10700 sampling. BOTTOM: Exoplanet detection limits on HD128621 HARPS spectra. We derived the detection limit maps by injecting simulated planetary signals covering periods ranging from 10 to 300 days and semiamplitude ranging from 0.4 to 1.1 m/s, into the spectra. Left: Detection limit map in the period-amplitude domain. The red dots indicate the successful detection by the trained neural network of a signal with a FAP > 0.1%. Middle: Amplitude comparison between the injected and recovered signals in the period amplitude domain. The amplitude difference for most of the detected signals is < 30%. Right: Phase difference between the injected and recovered signals in the period-amplitude domain. The phase difference for most of the detected signals is < 0.06. -- astro-ph.EP

Alpha Centauri, Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, tau Ceti

Improving Earth-like Planet Detection in Radial Velocity Using Deep Learning

by Keith CowingMay 24, 2024May 24, 2024

Many novel methods have been proposed to mitigate stellar activity for exoplanet detection as the presence of stellar activity in radial velocity (RV) measurements is the current major limitation.

Gliese 12 b’s estimated size may be as large as Earth or slightly smaller — comparable to Venus in our solar system. This artist’s concept compares Earth with different possible Gliese 12 b interpretations, from one with no atmosphere to one with a thick Venus-like one. CREDIT NASA/JPL-Caltech/R. Hurt (Caltech-IPAC)

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release, Venus

Gliese 12 b, A Potentially Habitable Exo-Venus With Earth-like Temperature

by Keith CowingMay 23, 2024May 23, 2024

Astronomers have made the rare and tantalising discovery of an Earth-like exoplanet 40 light-years away that may be just a little warmer than our own world.

Concept figure illustrating a hypothetical Earth-like inhabited planet terraformed with various combined abundances of artificial greenhouse gases C3F8, C2F6, and SF6 and its resulting qualitative mid-infrared transmission (top) and emission (bottom) spectra. The figure conveys the anomalously high absorption opacity that may be detected when characterizing an exoplanet whose climate is modified by these artificial gases, which span the key mid-infrared window wavelengths. (Graphic artist: Sohail Wasif, UC Riverside). -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Habitable Zones, Imaging & Spectroscopy, SETI & Technosignatures, Status Report

Artificial Greenhouse Gases as Exoplanet Technosignatures

by Keith CowingMay 21, 2024June 26, 2024

Atmospheric pollutants such as CFCs and NO2 have been proposed as potential remotely detectable atmospheric technosignature gases. Here we investigate the potential for artificial greenhouse gases including CF4, C2F6, C3F8, […]

Biophysics, Biosignatures & Paleobiology, Cryobiology, Extremeophiles and Extreme Environments, Habitable Zones, Icy Worlds, Mars, Microbiology & Virology, Status Report

Preservation of Bacillus subtilis’ Cellular Liquid State at Deep Sub-zero Temperatures In Perchlorate Brines

by Keith CowingMay 20, 2024May 20, 2024

Although a low temperature limit for life has not been established, it is thought that there exists a physical limit imposed by the onset of intracellular vitrification, typically occurring at […]

Joint constraints on the H2/He abundance and the atmospheric pressure on TRAPPIST-1 b resulting from the sequential fit of the stellar contamination and planetary atmosphere. The color shading illustrates the posterior probability density, where darker colors correspond to higher probabilities. Contours indicate the 1σ, 2σ, and 3σ Bayesian credible regions. The displayed posterior probability is marginalized over the H2O, CH4, CO, CO2, NH3, and N2 abundances. Hydrogen-dominated scenarios with high-altitude clouds are at the top left corner of the plot and cloud-free, volatile-rich, high-mean-molecular-mass atmospheres are at the bottom right. Any hydrogen-rich atmospheres without high-altitude clouds, at the bottom left, are robustly ruled out. The second horizontal axis at the top shows the mean molecular mass representative for a pure H2/H2O atmosphere. -- The Astrophysical Journal Letters

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Bathymetry, Press Release

JWST’s First Spectrum Of TRAPPIST-1 b

by Keith CowingMay 18, 2024May 18, 2024

In a solar system called TRAPPIST-1, 40 light years from the sun, seven Earth-sized planets revolve around a cold star.

Cross-correlation maps produced using models broadened to the measured rotational broadening of each molecule. These CCFs are predicted to show stronger detections as the models used more closely match the broadened planetary lines in the data, and the influence of noise sources on the scale of a single resolution element in the CCF are suppressed. Most notably, when cross-correlating with an SiO model broadened to the 22 km s−1 rotational broadening measured from the H2O CCF, the evidence for the tentative SiO signal increases to an S/N = 4.3, while other regions are suppressed, suggesting a potential planetary origin. The CO signal is boosted to S/N = 6.6 and the H2O signal is now above the S/N = 5 threshold for a detection, with an S/N = 5.7. Cross-correlation with a broadened model containing CO, H2O, and SiO produces the strongest detection of all models tested, with a S/N = 7.5. The CCFs produced using the H2O model and the model containing all three molecular opacities show an offset from the expected velocity, which is discussed further in Section 6.3. To reduce the impact of correlated signals the noise estimates for these CCFs are measured from a down-sampled CCF, with the planet signal excluded (see Section 4.7). For clarity, and following the convention for HCS, the CCFs are presented here at the 1.5 km s−1 CRIRES+ pixel resolution. -- astro-ph.EP

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

Into The Red: An M-band Study of the Chemistry and Rotation of β Pictoris b at High Spectral Resolution

by Keith CowingMay 16, 2024May 16, 2024

High-resolution cross-correlation spectroscopy (HRCCS) combined with adaptive optics has been enormously successful in advancing our knowledge of exoplanet atmospheres, from chemistry to rotation and atmospheric dynamics.

habitability

Paths To Robust Exoplanet Science Yield Margin For The Habitable Worlds Observatory

Lethal Surface Ozone Concentrations Are Possible On Habitable Zone Exoplanets

Observation of Significant Photosynthesis in Garden Cress and Cyanobacteria under Simulated Illumination from a K Dwarf Star

MHD Simulations of the Space Weather in Proxima b: Habitability Conditions and Radio Emission

Improving Earth-like Planet Detection in Radial Velocity Using Deep Learning

Gliese 12 b, A Potentially Habitable Exo-Venus With Earth-like Temperature

Artificial Greenhouse Gases as Exoplanet Technosignatures

Preservation of Bacillus subtilis’ Cellular Liquid State at Deep Sub-zero Temperatures In Perchlorate Brines

JWST’s First Spectrum Of TRAPPIST-1 b

Into The Red: An M-band Study of the Chemistry and Rotation of β Pictoris b at High Spectral Resolution

How High-pressure Ices On Large Ocean Worlds Can Support Habitability: The Compatibility Of Amino Acids Into Ice VI And VII

Ice Drives The Emergence Of Functional Protocells

Chemical Abundance Patterns at z=1-7: Carbon, Nitrogen, Neon, Sulphur, and Argon Abundances From JWST Spectroscopy

Optimization of Petal-Shaped Occulters for Exo-Earth Observation

Topographically Forced Stationary Waves Can Explain The Near-Surface Zonal Winds Observed By Huygens On Titan