Sun Archives - Astrobiology

[NSF/AURA] This newly released image from the National Science Foundation (NSF) was taken by the Daniel K. Inouye Solar Telescope is the largest solar telescope in the world.

Space Weather & Heliophysics

Our Local Star

by Keith CowingJuly 12, 2026July 12, 2026

[NSF/AURA] This newly released image from the National Science Foundation (NSF) was taken by the Daniel K. Inouye Solar Telescope is the largest solar telescope in the world. This view […]

Time series of atmospheric temperature and He column density for the observation day January 26, 2023. Blue and gray points represent the 20x binned and unbinned best-fit planetary parameters obtained from fitting the planetary absorption spectra as described in Sect. 3.3.2. The red line marks the weighted average of each retrieved parameter and the orange band represents the 1 σ region around this average. The black line shows the input values used in the simulation. We provide axes for the width in km/s and depth in % to facilitate the understanding of the analogy between temperature and width, and column density and depth. -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Space Weather & Heliophysics, Status Report

Studying The Variability Of The He Triplet To Understand The Detection Limits Of Evaporating Exoplanet Atmospheres

by Keith CowingJuly 31, 2025July 31, 2025

With more than a dozen significant detections, the helium triplet has emerged as a key tracer of evaporating exoplanet atmospheres.

Scatter plot of the flare energy as a function of spot group area for solar flares (black dots) and superflares of G-type stars from the Kepler sample by Okamoto et al. (2021). Left panel: Original Sun-like sample from Okamoto et al. (2021). Right panel: Updated solar observations based on the rescaling discussed in Hudson et al. (2024) (purple dots) and updated stellar sample utilizing the updated spot group area function by Herbst et al. (2021) (blue dots and according errors). -- astro-ph.SR

Astronomy & Telescopes, Atmospheres, Climate, Weather, Habitable Zones, Space Weather & Heliophysics, Status Report, Stellar Cartography

Comparing The Sun To Sun-like Stars. On The Importance Of Addressing Faculae/spot Domination

by Keith CowingApril 4, 2025April 4, 2025

Whether the Sun is an ordinary G-type star is still an open scientific question.

Trajectories of the Sun on the R-tbk planes for the evolving model. The orange lines show the trajectories of “trapped migrators,” while the green lines depict “untrapped migrators.” Thick lines represent the trajectories of Sun-like particles, while thin lines show orbits similar to those indicated by the thick lines. The background colors with contours indicate (a) the SFR density (ΣSFR) and (b) lethal GRB event rates (NGBR), based on the Galactic chemical evolution model (Baba et al. 2023). The black dashed lines indicate the locations of the bar’s CR and OLR radii. -- astro-ph.GA

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

Solar System Migration Points to a Renewed Concept: Galactic Habitable Orbits

by Keith CowingDecember 5, 2024December 5, 2024

Astrophysical evidence suggests that the Sun was born near 5 kpc from the Galactic center, within the corotation radius of the Galactic bar, around 6-7 kpc.

The GCE-corrected, differential elemental abundance relative to the Sun ([X/Fe]solar - [X/Fe]star). The five solar twins with -0.1 < [Fe/H] < 0.1 dex, ∆ Teff < 100 K, ∆ log g < 0.1 are TOI-1055, TOI-2426, TOI-744, TOI-755, and TOI-818, are shown as gray symbols in the background, while the colored symbols show the average elemental abundance for these stars. Refractory elements are shown in orange, volatile elements are shown in blue symbols. Elements with Tc above 1300 K are considered refractory, with the threshold Tc of 1300 K shown by a dashed orange line. We fit a linear regression to the colored symbols while considering the error bars. The orange line displays the best linear fit to all the colored points, with the shaded blue band indicating the 1-σ confidence interval. The expression for the linear regression is -6.726e-05+2.320e−05 −2.342e−05 × Tc (K) + 0.086+0.030 −0.030. -- astro-ph.SR

Astrochemistry, Astronomy & Telescopes, Imaging & Spectroscopy, Space Weather & Heliophysics, Status Report, Stellar Cartography

High Precision Stellar Chemical Abundance for 17 Planet-hosting Stars and the Condensation Temperature Trend

by Keith CowingNovember 24, 2024November 24, 2024

The Sun is depleted in refractory elements compared to nearby solar twins, which may be linked to the formation of giant or terrestrial planets.

Graphical Abstract -- astro-ph.SR

Habitable Zones, Magnetic Fields, Electromagnetism, bioelectricity,, Radiation, Space Weather & Heliophysics, Status Report

Space Weather Forecasts: Monitoring The Daily Variation of Sun-Earth Magnetic Fields Using Galactic Cosmic Rays

by Keith CowingOctober 16, 2024October 16, 2024

The interplanetary magnetic field (IMF) between the Sun and Earth is an extension of the solar magnetic field carried by the solar wind into interplanetary space.

The sun sets over NASA's Kennedy Space Center in Florida, on October 13, 2010. Larger image NASA/Dimitri Gerondidakis

Habitable Zones, Radiation, Space Weather & Heliophysics, Status Report

Transition To A Weaker Sun: Changes In The Solar Atmosphere During The Decay Of The Modern Maximum

by Keith CowingMarch 15, 2024March 15, 2024

The Sun experienced a period of unprecedented activity during the 20th century, now called the Modern Maximum (MM). The decay of the MM after cycle 19 has changed the Sun, […]

Magnification: 160x, bright field (negative image), stacked image Fundort / Site: Barbados Alter / Age: approx. 32-35 million years (late Eocene - early Oligocene) Präparation / Preparation: Andreas Drews Radiolarians are unicellulars of diameter 0.1–0.2 mm that produce intricate mineral skeletons, typically with a central capsule dividing the cell into the inner and outer portions of endoplasm and ectoplasm.The elaborate mineral skeleton is usually made of silica. They are found as zooplankton throughout the ocean, and their skeletal remains make up a large part of the cover of the ocean floor as siliceous ooze. Due to their rapid turn-over of species, they represent an important diagnostic fossil found from the Cambrian onwards. -- Wikipedia

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Fossils & Paleontology, Microbiology & Virology, Origin & Evolution of Life, Status Report, Stellar Cartography, Water/Hycean Worlds & Oceanography

Cosmic Radiation Drives Quasi-periodic Changes In The Diversity Of Siliceous Marine Microplankton

by Keith CowingFebruary 15, 2024

Radiolarians are significant contributors to the oceanic primary productivity and the global silica cycle in the last 500 Myr. Their diversity throughout the Phanerozoic shows periodic fluctuations.

Astrobiology (general), Habitable Zones, Press Release

How Early Earth Kept Warm Enough to Support Life

by Keith CowingJuly 9, 2013

Solving the “faint young Sun paradox” — explaining how early Earth was warm and habitable for life beginning more than 3 billion years ago even though the Sun was 20 […]