GALEX Archives - Astrobiology

Main panel: comparison among ATLAS9 fluxes for the Sun calculated with suitable ODFs adopting different solar chemical mixtures

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Press Release

KOALA, A New ATLAS9 Database — I. Model atmospheres, Opacities, Fluxes, Bolometric Corrections, Magnitudes And Colours

by Keith CowingJanuary 22, 2026January 22, 2026

We present the KOALA database, a new set of LTE, line-blanketed model atmospheres calculated with the code ATLAS9, together with the corresponding Opacity Distribution Functions and emergent fluxes.

Panel (a): H–R diagram of the open cluster members stars with GALEX observations. The blue solid line is the fitting results of main sequences. green dashed lines represent the upper and lower bounds of the main sequence fitted with a ±0.5 offset, and the red dashed lines is the same sequence shifted upwards by 2. Panel (b): H–R diagram of the field stars with GALEX observations. Panel (c): The galactic distribution of the selected sources from open clusters. The color bar represent the age of the stars. Panel (d): The galactic distribution of the selected sources from field stars. -- astro-ph.SR

Exoplanets, -moons, -comets, Habitable Zones, Space Weather & Heliophysics, Status Report, Stellar Cartography

Evolution of Stellar Activity and Habitable zone: I. Ultraviolet Emission of Dwarfs in Open Clusters and Field Stars

by Keith CowingSeptember 24, 2025

Near-ultraviolet (NUV) radiation from dwarf stars plays a critical role in shaping the habitability of planetary systems, yet its long-term evolution across different spectral types remains poorly investigated.

Left panel: The relation between the effective temperatures of the host stars and the effective fluxes incident on their planets. The blue, green, orange, and red dots represent gas giants, Neptunian-like planets, super-Earths, and terrestrial planets, respectively. The gray shaded area is the CHZ for each star, and the black, red, and purple lines represent the inner and outer boundaries of the CHZ for Earth mass, 5 Earth masses, and 0.1 Earth masses, respectively. Note that the three outer boundary lines overlap. The black dots represent the planets in our Solar System. Right panel: the relation between the NUV luminosities of the host stars and the distances between the stars and their planets. The pink, green, and blue shaded areas represent the UHZ for different NUV transmission rates of planetary atmospheres. The blue, green, orange, and red asterisks represent gas giants, Neptunian-like planets, super-Earths, and terrestrial planets that are located within both the CHZ and UHZ. -- astro-ph.SR

Astronomy & Telescopes, Biosignatures & Paleobiology, Habitable Zones, Imaging & Spectroscopy, Status Report, Stellar Cartography

Ultraviolet Photometry and Habitable Zones of Over 2700 Planet-Hosting Stars

by Keith CowingNovember 1, 2024November 1, 2024

The ongoing discovery of exoplanets has sparked significant interest in finding suitable worlds that could potentially support life. Stellar ultraviolet (UV; 100-3000 Å) radiation may play a crucial role in […]

Artist rendition of DG CVn, a binary star system made up of two red dwarf stars. Illustration shows it unleashing powerful flares that could impact planet habitability. CREDIT NASA

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Press Release, Radiation, Space Weather & Heliophysics

Understanding The Stellar Flare Risks To Planets That Could Host Life

by Keith CowingAugust 5, 2024August 5, 2024

A groundbreaking study has revealed that red dwarf stars can produce stellar flares that carry far-ultraviolet (far-UV) radiation levels much higher than previously believed. This discovery suggests that the intense […]

Setting The Stage For The Search For Life With The Habitable Worlds Observatory: Properties Of 164 Promising Planet-survey Targets

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

Setting The Stage For The Search For Life With The Habitable Worlds Observatory: Properties Of 164 Promising Planet-survey Targets

by Keith CowingJuly 18, 2024August 2, 2024

The Decadal Survey on Astronomy and Astrophysics 2020 has recommended that NASA realize a large IR/optical/UV space telescope optimized for high-contrast imaging and spectroscopy of ∼25 exo-Earths and transformative general […]

Comparison of flare rates from young planet host stars with respect to a comparable sample with respect to age [Myr] and Teff [K]. Circles represent the flare rate of the host star (name along the x-axis); vertical bars represent the lower 16th and upper 84th percentiles for the comparable sample. The majority of young planet host stars have comparable flare rates to the lower end of the comparison sample. A handful of hosts have more flares, including HIP 67522, AU Mic, DS Tuc A, and TOI 451. We find no correlation with spectral type or age which may indicate why these host stars are relatively flare quiet. The measured flare rates are presented in Table 2. -- astro-ph.SR

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Radiation, Space Weather & Heliophysics, Status Report, Stellar Cartography

Evolution of Flare Activity in GKM Stars Younger than 300 Myr over Five Years of TESS Observations

by Keith CowingMay 3, 2024

Stellar flares are short-duration (< hours) bursts of radiation associated with surface magnetic reconnection events. Stellar magnetic activity generally decreases as a function of both age and Rossby number, R0, […]