Habitable Zone Archives

125 flares discovered in CM Draconis, stacked together and aligned to have a peak at 𝑡 = 0.

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Proxima Centauri, Radiation, Space Weather & Heliophysics, Status Report, Stellar Cartography, TRAPPIST-1

Identifying Flare Locations Through Exoplanet Transit Occultations

by Keith CowingJanuary 11, 2025

M dwarfs are the most common stars in the galaxy, with long lifespans, a high occurrence rate of rocky planets, and close-in habitable zones.

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biophysics, Biosignatures & Paleobiology, Extremeophiles and Extreme Environments, Habitable Zones, Microbiology & Virology, Status Report, Water/Hycean Worlds & Oceanography

The Role Of Atmospheric Composition In Defining The Habitable Zone Limits And Supporting E. coli Growth

by Keith CowingJanuary 11, 2025January 11, 2025

Studying exoplanet atmospheres is essential for assessing their potential to host liquid water and their capacity to support life (their habitability).

Differential transmission spectra of various superhabitable (SH) planet scenarios, as well as Kepler-62e and modern Earth around the Sun, calculated using the forward model code POSEIDON. Spectral features are displayed in parts per million (ppm) relative to each planet's baseline transit depth, enhancing the visibility of individual molecular signatures. Key absorption features of major atmospheric constituents, including O2 , O3 , CH4 , H2O, N2O, CO2 , CH3Cl, and CO, are indicated (see Table 3). Line descriptions are consistent with those in Figure 3. Solid gray lines represent SH planets receiving an incident stellar flux of 0.8 solar constants (S0 = 1366 W/m2 ), positioned between the inner edge and center of their respective host star’s habitable zone (HZ), while dashed lines represent SH planets at 0.6 S0 , aligned with the center of the HZ. -- astro-ph.EP

Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography

Superhabitable Planets Around Mid-Type K Dwarf Stars Enhance Simulated JWST Observability and Surface Habitability

by Keith CowingJanuary 8, 2025January 8, 2025

In our search for life beyond the Solar System, certain planetary bodies may be more conducive to life than Earth. However, the observability of these `superhabitable’ planets in the habitable […]

Snapshots show planetary seeds’ growth and migration from two rings of material. This simulation comes from our M6T2 scenario. The top-left panel shows the starting time of the simulation. The time of each snapshot is shown on the bottom-left of each panel. The color of each dot corresponds to the water mass fraction of each planetary seed. We plot planetesimal and pebble isolation masses with dotted and dashed lines, respectively. The planetesimal isolation mass is obtained by extrapolating the initial surface density of the inner planetesimal disk. The vertical blue dashed line shows the location of the water condensation line. The blue solid line is the boundary of the inward and outward migration where the migration torque is zero. -- astro-ph.EP

Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Status Report, Water/Hycean Worlds & Oceanography

Formation of Super-Earths and Mini-Neptunes From Rings of Planetesimals

by Keith CowingJanuary 8, 2025

The solar system planetary architecture has been proposed to be consistent with the terrestrial and giant planets forming from material rings at ~1 au and ~5 au, respectively.

Time averages of the surface temperature for the 1st quintile of the training and test models in rotation period, ordered fastest to slowest. While the rotation periods are organized in increasing order from top left to bottom right, the remaining spin and orbital parameters (obliquity, eccentricity, and longitude of periapse) vary according to the configuration from the Latin Hypercube Sampling algorithm, and are themselves not in any particular order. -- astro-ph.EP

Analog Studies, Astrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Status Report, Water/Hycean Worlds & Oceanography

Habitability in 4-D: Predicting the Climates of Earth Analogs across Rotation and Orbital Configurations

by Keith CowingJanuary 7, 2025January 7, 2025

Earth-like planets in the circumstellar habitable zone (HZ) may have dramatically different climate outcomes depending on their spin-orbit parameters, altering their habitability for life as we know it.

A schematic illustrating habitability of physical spaces as a function of physical and chemical conditions. The diagram is a simplified depiction of niche space (here three dimensions are shown – in reality, the space is an n-dimensional hypervolume) and the extent to which these niche conditions are occupied in physical spaces. The habitable space for life is enclosed within a much larger (red) space that is uninhabitable (also see Figure 4). The blue object represents habitable space that is inhabited. At the edge of this habitable and inhabited set of physical and chemical conditions is a putative yellow ‘rind’ of habitat space at the edges of life which could be inhabited by life with appropriate evolutionary innovations. Within the habitable and inhabited space there are grey shapes depicting localized physical spaces that are habitable, but uninhabited (uninhabited habitats). The purpose of the schematic is to illustrate that uninhabited, but habitable spaces exist both within physical spaces that are known to be permissive for microbial growth and potentially at the limits of life at extremes. Life, especially using technology, can establish itself in conditions away from the blue spheroid with appropriate expenditure of energy (e.g., a self-sustaining space settlement), shown as isolated blue objects in the red space. -- FEMS Microbiology Reviews

Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Extremeophiles and Extreme Environments, Fossils & Paleontology, Habitable Zones, Microbiology & Virology, Origin & Evolution of Life, Plant Biology, Status Report

Where The Microbes Aren’t

by Keith CowingDecember 27, 2024December 27, 2024

Although a large fraction of Earth’s volume and most places beyond the planet lack life because physical and chemical conditions are too extreme, intriguing scientific questions are raised in many […]

This artistic illustration shows how the early Earth might have looked under bombardment, with circular impact features dotting the daylight side, while hot lava glows on the night side. A thick, yellowish hazy atmosphere is also present. SwRI scientists created a new model for impact-generated outgassing on the early Earth. Image Courtesy of Simone Marchi (SwRI).

Astrobiology (general), Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Origin & Evolution of Life, Status Report, Water/Hycean Worlds & Oceanography

The First Billion Years: Habitability

by Keith CowingDecember 26, 2024December 26, 2024

The physical processes active during the first billion years (FBY) of Earth’s history, such as accretion, differentiation, and impact cratering, provide constraints on the initial conditions that were conducive to […]

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Conferences and Meetings, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Bathymetry, Status Report, Water/Hycean Worlds & Oceanography

Towards the Habitable Worlds Observatory: Visionary Science and Transformational Technology

by Keith CowingDecember 20, 2024

We are pleased to announce the inaugural open community conference for NASA’s Habitable Worlds Observatory, to be held at the Johns Hopkins Bloomberg Center in Washington, DC, from July 28‐31, […]

Transmission spectra for the biotic scenarios. We show the JWST/NIRSpec range between 3 – 5 micron with a continuous grey cloud deck at the p = 0.01 bar (solid lines) and the dry biotic scenarios 1 & 2 with a lower cloud deck at the p = 0.1 bar (dashed line). The inlay for the 3.2 – 3.35 micron range highlights the O3 (grey box) and CH4 feature (magenta box). We further simulated JWST observations with PANDEXO for the dry biotic scenarios 1 & 2 with the lower cloud deck, simulating 100 transit observations of TRAPPIST-1e (black error bars). We chose the G395M grism setting and combined 10 pixels in one bin. -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Origin & Evolution of Life, Status Report

The Effect of a Biosphere on the Habitable Timespan of Stagnant-lid Planets and Implications for the Atmospheric Spectrum

by Keith CowingDecember 18, 2024December 19, 2024

Temperature-dependent biological productivity controls silicate weathering and thereby extends the potential habitable timespan of Earth.

A parameter space plot showing ocean survival plotted by planet final semi-major axis and the time since white dwarf formation at which the scattering event occurred. This plot was constructed for an Earth-like planet with an initial semi-major axis of 5 AU, varying initial eccentricity, and an initial ocean mass of 1 TO. The location of the habitable zone, defined by where water could be liquid on the surface of an Earth-like planet, is overlaid. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Status Report, Water/Hycean Worlds & Oceanography

The Fate of Oceans on First-Generation Planets Orbiting White Dwarfs

by Keith CowingDecember 18, 2024December 19, 2024

Several groups have recently suggested that small planets orbiting very closely around white dwarf stars could be promising locations for life to arise, even after stellar death. There are still […]

Habitable Zone

Identifying Flare Locations Through Exoplanet Transit Occultations

The Role Of Atmospheric Composition In Defining The Habitable Zone Limits And Supporting E. coli Growth

Superhabitable Planets Around Mid-Type K Dwarf Stars Enhance Simulated JWST Observability and Surface Habitability

Formation of Super-Earths and Mini-Neptunes From Rings of Planetesimals

Habitability in 4-D: Predicting the Climates of Earth Analogs across Rotation and Orbital Configurations

Where The Microbes Aren’t

The First Billion Years: Habitability

Towards the Habitable Worlds Observatory: Visionary Science and Transformational Technology

The Effect of a Biosphere on the Habitable Timespan of Stagnant-lid Planets and Implications for the Atmospheric Spectrum

The Fate of Oceans on First-Generation Planets Orbiting White Dwarfs

COP31 Ice Planet Update: Earth’s Cryosphere Decline Is Beyond Safe Planetary Limits

Possible Lake Remnants Inside a Crater at the Edge of Isidis Planitia, Mars

Seven Genome Sequences Of Bacterial Environmental Isolates From The Western Coast Of The Greenland Ice Sheet

Cosmic-ray Particles Can Help Probe The Powerful Electric Fields Inside Earth’s Thunderstorms

When Communication Enables Catastrophe: Nuclear Risk and the Short Lifetimes of Technological Civilizations: A Bayesian Scenario Analysis of Civilizational Survival and the Fermi Paradox