Results 31 to 40 of about 528 (133)

MAGNETIC UPFLOW EVENTS IN THE QUIET-SUN PHOTOSPHERE. I. OBSERVATIONS [PDF]

open access: yesThe Astrophysical Journal, 2015
12 pages, 6 figures, 2 ...
S. Jafarzadeh   +2 more
openaire   +3 more sources

Hidden No More: Spotlight on Tidal Disruption Events in Active Galactic Nuclei

open access: yesAstronomische Nachrichten, Volume 347, Issue 5, June 2026.
ABSTRACT Tidal disruption events (TDEs) are typically discovered in previously quiescent galaxies. However, earlier studies have revealed a handful of TDEs occurring in pre‐existing active galactic nuclei (AGN). We discuss AT2019aalc, a promising TDE candidate in an AGN, and compare it to similar sources.
Patrik Milán Veres
wiley   +1 more source

PHOTOSPHERIC ABUNDANCES OF POLAR JETS ON THE SUN OBSERVED BYHINODE [PDF]

open access: yesThe Astrophysical Journal, 2015
Many jets are detected at X-ray wavelengths in the Sun's polar regions, and the ejected plasma along the jets has been suggested to contribute mass to the fast solar wind. From in-situ measurements in the magnetosphere, it has been found that the fast solar wind has photospheric abundances while the slow solar wind has coronal abundances. Therefore, we
Kyoung-Sun Lee   +2 more
openaire   +2 more sources

Comparing Solar Structure Detection Methods in SDO/AIA Observations and the Application to Raw Uncalibrated Data

open access: yesJournal of Geophysical Research: Machine Learning and Computation, Volume 3, Issue 3, June 2026.
Abstract Recent advances in solar physics increasingly rely on automated identification of coronal structures using machine learning. Yet most studies emphasize scientific performance without evaluating feasibility for onboard deployment to prioritize downlink observations.
P. Gonidakis   +11 more
wiley   +1 more source

Identifying and Predicting Coronal Mass Ejection Occurrence: Observational Checklists for Space Weather Forecasters

open access: yesSpace Weather, Volume 24, Issue 6, June 2026.
Abstract Ejections of magnetized plasma from the Sun, known as coronal mass ejections, can drive major geomagnetic activity if Earth‐directed, and are therefore monitored by space weather forecasters. The current focus being the forecast of the arrival time of a coronal mass ejection at Earth and the level of geomagnetic impact.
L. M. Green   +7 more
wiley   +1 more source

Extreme Value Analysis of Solar Green‐Line Corona During the Time Interval 1939–2025

open access: yesSpace Weather, Volume 24, Issue 5, May 2026.
Abstract Predicting the probability of extreme solar events is critical to understanding how to mitigate risks associated with space weather disasters, as their occurrence can pose a threat to life and infrastructure on Earth or in near‐Earth orbit. In the present study, extreme value theory is applied to the daily modified coronal index (MCI) for the ...
Miao Wan   +6 more
wiley   +1 more source

CI chondrite Oued Chebeika 002 links asteroids Bennu and Ryugu to common parent body

open access: yesMeteoritics &Planetary Science, Volume 61, Issue 5, Page 801-818, May 2026.
Abstract CI chondrites are a compositionally primitive group of meteorites that have undergone extensive aqueous alteration, providing insights into the evolution of primitive planetesimals. Oued Chebeika 002 is the most pristine CI chondrite to date.
Megan Broussard   +11 more
wiley   +1 more source

Ryugu reference project: Recommendations from the measurement definition team

open access: yesMeteoritics &Planetary Science, Volume 61, Issue 5, Page 819-848, May 2026.
Abstract Sample return missions play a significant role in planetary science by providing pristine extraterrestrial materials. JAXA's Hayabusa2 and NASA's OSIRIS‐REx missions have returned samples from the C‐type asteroids Ryugu and Bennu, respectively. The chemical and mineralogical compositions of these samples closely resemble those of CI chondrites,
Tetsuya Yokoyama   +16 more
wiley   +1 more source

Spectral Irradiance Observations and Projections for Solar Cycle 25

open access: yesEarth and Space Science, Volume 13, Issue 4, April 2026.
Abstract The Ozone Monitoring Instrument (OMI) on the Aura satellite makes near‐daily measurements of solar spectral irradiance (SSI) at wavelengths between 265 and 500 nm for instrument calibration purposes. The low degradation and exceptional stability of OMI's calibration during its lifetime facilitates the creation of a new 18‐year OMI Version 7 ...
Matthew T. DeLand   +3 more
wiley   +1 more source

Reconstruction of Two‐Dimensional Magnetohydrodynamic and Hall Magnetohydrodynamic Equilibria in Space Using Physics‐Informed Neural Networks

open access: yesJournal of Geophysical Research: Machine Learning and Computation, Volume 3, Issue 2, April 2026.
Abstract We present a novel data analysis technique based on physics‐informed neural networks (PINNs) to reconstruct two‐dimensional (2D) magnetohydrodynamic (MHD) and Hall MHD equilibria in a space plasma from in situ spacecraft measurements. Our method incorporates the steady‐state MHD or Hall MHD equations—a set of partial differential equations ...
Hiroshi Hasegawa   +3 more
wiley   +1 more source

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