Habitable Zone Archives - Page 16 of 66 - Astrobiology

Concept drawings of four of the large-aperture direct imaging space telescopes envisioned and studied over the past 25 years. Note that the separation depicted here between the starshade and the HabEx spacecraft is not to scale. The starshade would typically be tens of thousands of km from the telescope. -- astro-ph.IM

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

The Habitable Worlds Observatory In Historical Context

by Keith CowingFebruary 17, 2026February 17, 2026

The Habitable Worlds Observatory (HWO) is humanity’s most ambitious scientific endeavor to explore nearby sun-like stars for the presence of habitable rocky exoplanets and the possible presence of life.

EAI Seminar: Deep microbial Colonization During Impact-generated Hydrothermal Circulation Of Impact Structures (Video)

Astrogeology, Away Teams & Field Reports, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Extinction events, Gaia - Planetary Perspectives, Habitable Zones, Impact events, Meteorites & Asteroids, Microbiology & Virology, Origin & Evolution of Life, Polar / Alpine Expeditions, Status Report, Video, Audio, Webcasts, Podcasts

EAI Seminar: Deep Microbial Colonization During Impact-generated Hydrothermal Circulation Of Impact Structures (Video)

by Keith CowingFebruary 16, 2026February 16, 2026

Henrik Drake, Professor, Linnaeus University, SwedenTuesday 10th February 2016, 16:00 CET

Strength of key long-term feedbacks governing Earth’s climate system (Forster et al. 2021; Arnscheidt & Rothman 2020; Abbot 2016; Koll & Cronin 2018). Each bar represents the feedback parameter in W m−2 K −1 , estimated from Earth system model assessments and paleoclimate constraints. The upper axis shows the approximate feedback strength associated with a 50 K climate perturbation, representative of transitions between major states (e.g., snowball to temperate). Feedbacks are sorted by magnitude. Negative values (blue) represent stabilizing feedbacks that damp temperature changes, while positive values (orange) indicate destabilizing feedbacks that amplify them. Outgoing longwave radiation and the carbonate–silicate cycle are among the strongest stabilizing processes, while the ice–albedo feedback exerts a strong destabilizing influence. Models incorporating the three dominant feedbacks explain the general behavior of Earth’s long-term mean climate. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Status Report

Not Earth-like Yet Temperate? More Generic Climate Feedback Configurations Still Allow Temperate Climates in Habitable Zone Exo-Earth Candidates

by Keith CowingFebruary 14, 2026February 14, 2026

Earth’s climate is influenced by over a dozen feedbacks, but only three dominate its long-term climate behavior. Models of the exoplanet habitable zone (HZ) assume that this is similar for […]

Schematic of some of the key processes throughout planet formation that influence carbon supply and retention. (a) Key ice/grain sublimation fronts in the disk noted (CO2 between water–CO and that of Silicates at inner disk edge not shown). Planets forming in these locations will receive different compositions at birth (Öberg et al. 2011). Dust that grows beyond the “soot” line (Lodders 2004, Kress et al. 2010, Li et al. 2021) will be rich in refractory carbon content and at greater distances molecular ices. (blow-out:) The drift of carbon-rich pebbles from the outer disk is a key process in carbon supply. Drift itself is influenced by pressure bumps that can lead to a pile-up of pebbles that can be potential sites for planetesimal and planet formation (shown on left side of disk). (b) Solids accrete ice mantles, sublimate key components at sublimation fronts and can collide leading to both growth and fragmentation. (c) Rocky planets and cores of gas-rich planets grow and gain carbon through accretion of pebbles (top) and/or planetesimals (bottom). Impacts of larger planetesimals can also strip atmospheric gas and also supply material. (d) heavy element differentiation can take carbon to the core, and the resulting magma ocean/atmosphere equilibrium can influence atmospheric composition with lighter gases escaping depending on the planet mass. Figure credit to N. Fuller and Sayo Studio. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gas Giants, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Press Release

Carbon From Interstellar Clouds To Habitable Worlds

by Keith CowingFebruary 12, 2026February 12, 2026

Carbon is an essential element for a habitable world. Inner (r < 3 au) disk planetary carbon compositions are strongly influenced by supply and survival of carbonaceous solids. Here we […]

The observed sources and data collected during the K2-18b observing campaign. (Left) The dates of the observations and the frequencies in which signals were detected. (Right) The location of the 64 coherent beams (gray circles), the position of K2-18 (red star), and the FWHM PB for the MeerKAT telescope at L-band. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Intelligence & Language, SETI & Technosignatures, Status Report, Water/Hycean Worlds & Oceanography

A Narrowband Technosignature Search Toward The Hycean Candidate K2-18b Using The VLA And MeerKAT

by Keith CowingFebruary 11, 2026February 11, 2026

K2-18b, a sub-Neptune exoplanet located in the habitable zone of its host star, has emerged as an important target for atmospheric characterization and assessments of potential habitability.

sBGLS periodograms of all planet candidates and the rotation period of the star. The apparent fringe pattern in all panels is caused by the sampling of the data in two chunks separated by approximately 13 y. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Proxima Centauri, Status Report

RedDots: Multiplanet System Around M Dwarf GJ 887 In The Solar Neighborhood

by Keith CowingFebruary 11, 2026February 11, 2026

GJ 877 is a bright M dwarf in the solar neighborhood with two currently reported nontransiting exoplanets with periods of 9 d and 21 d, along with an additional unconfirmed […]

Left panel: Map of the normalized XUV flux in the habitable zone, FXUV,HZ/FHZ, in the Galactic R-Z plane. Right panel: Map of the normalized XUV flux in the habitable zone, FXUV,HZ/FHZ, in the Galactic X-Y plane. -- astro-ph.SR

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biophysics, Exoplanets, -moons, -comets, Habitable Zones, Press Release, Radiation

Probing Habitable Regions With SRG/eROSITA

by Keith CowingFebruary 9, 2026February 9, 2026

Stellar high-energy radiation is a key driver of atmospheric erosion and evolution in exoplanets, directly affecting their long-term habitability.

Tidally Heated H2-Dominated Exomoon - Grok via Astrobiology.com

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

Habitability Of Tidally Heated H2-Dominated Exomoons Around Free-Floating Planets

by Keith CowingFebruary 6, 2026February 6, 2026

Exomoons around free-floating planets (FFPs) can survive their host planet’s ejection. Such ejections can increase their orbital eccentricity, providing significant tidal heating in the absence of any stellar energy source.

The distribution of currently known exoplanets from the NASA Exoplanet Archive that are in the VZ and have radii Rp ≲ 2 R⊕. The inner VZ boundary is indicated by the red line on the left, and the outer VZ boundary is shown on the right. As of November 2025 there are 370 potential exoVenuses, and this number will continue to grow as there are over 7000 TESS planet candidates yet to be confirmed. The VZ will be calculated and translated against the IWA for all proposed HWO priority targets. -- astro-ph.EP

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

Imaging Venus-like Worlds: Spectral, Polarimetric, And UV Diagnostics For The Habitable Worlds Observatory

by Keith CowingFebruary 5, 2026February 5, 2026

Understanding planetary habitability requires a comparative approach that explores the divergent evolutionary outcomes of Earth and Venus.

Left: Detection maps showing the percentage of recovered injected signals as a function of period and semi-amplitude for the narrow and wide BERV coverages. Middle: Same detection tests after applying the wapiti correction. Right: Difference between the recovered and injected K values (∆K = Kout − Kin) at 1 m·s −1 , with the shaded area indicating one standard deviation. The color bar indicates the detection rate in percent. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, Stellar Cartography

The SPIRou Legacy Survey: Detection Of A Nearby World Orbiting In The Habitable Zone Of Gl725B

by Keith CowingFebruary 5, 2026February 5, 2026

M dwarfs are prime targets in the search for exoplanets because of their prevalence and because low-mass planets can be better detected with radial velocity (RV) methods. In particular, the […]