Results 51 to 60 of about 14,687 (203)

Searching for Rotational X‐Ray Modulation on TIC 277539431

Astronomische Nachrichten, Volume 347, Issue 3, March 2026.
ABSTRACT TIC 277539431, a fast rotating M7 dwarf, was detected to host the highest latitude flare to date at 81°$$ {81}^{{}^{\circ}} $$. Magnetic activity like stellar flares occurring at high latitude indicate occurrence of coronal loops at these latitudes on fully‐convective M dwarfs. In contrast, sunspots usually occur below 30°$$ {30}^{{}^{\circ}} $
Desmond Dsouza, Katja Poppenhäger, Ekaterina Ilin   +2 more
wiley   +1 more source

New Insights into Type-I Solar Noise Storms from High Angular Resolution Spectroscopic Imaging with the Upgraded Giant Metrewave Radio Telescope

The Astrophysical Journal
Type-I solar noise storms are perhaps the most commonly observed active radio emissions from the Sun at meter-wavelengths. Noise storms have a long-lived and wideband continuum background with superposed islands of much brighter narrowband and short ...
Surajit Mondal, Devojyoti Kansabanik, Divya Oberoi, Soham Dey   +3 more
doaj   +1 more source

Radio observations of the quiet solar corona

Advances in Space Research, 1994
Abstract Observations of radio emission from the quiet solar atmosphere and the associated emission mechanisms are discussed. Long wavelength observations, with a spatial resolution of ∼1 arc min are ideal for the study of the large scale structure of the corona, including coronal holes, arches, streamers and the base of the heliospheric current ...
openaire   +2 more sources

Periodic Density Structures Observed in Ulysses Data: First Results

Journal of Geophysical Research: Space Physics, Volume 131, Issue 3, March 2026.
Abstract Periodic density structures (PDSs) are advecting quasi‐periodic (periodicities between several minutes and several hours) density enhancements observed in the solar wind and corona. There is strong evidence that PDSs are formed at the Sun.
Brent M. Randol, Nicholeen Viall, Larry Kepko, Simone Di Matteo   +3 more
wiley   +1 more source

Estimating Electron Densities in the Middle Solar Corona Using White-light and Radio Observations

The Astrophysical Journal
The electron density of the solar corona is a fundamental parameter in many areas of solar physics. Traditionally, routine estimates of coronal density have relied exclusively on white-light observations.
Surajit Mondal, Shaheda Begum Shaik, Russell A. Howard, Peijin Zhang, Bin Chen, Xingyao Chen, Sijie Yu, Dale Gary, Marin M. Anderson, Judd D. Bowman, Ruby Byrne, Morgan Catha, Sherry Chhabra, Larry D’Addario, Ivey Davis, Jayce Dowell, Gregg Hallinan, Charlie Harnach, Greg Hellbourg, Jack Hickish, Rick Hobbs, David Hodge, Mark Hodges, Yuping Huang, Andrea Isella, Daniel C. Jacobs, Ghislain Kemby, John T. Klinefelter, Matthew Kolopanis, Nikita Kosogorov, James Lamb, Casey Law, Nivedita Mahesh, Brian O’Donnell, Kathryn Plant, Corey Posner, Travis Powell, Vinand Prayag, Andres Rizo, Andrew Romero-Wolf, Jun Shi, Greg Taylor, Jordan Trim, Mike Virgin, Akshatha Vydula, Sandy Weinreb, Scott White, David Woody, Thomas Zentmeyer   +48 more
doaj   +1 more source

Are Nonthermal Velocities in Active Region Coronal Loops Anisotropic?

The Astrophysical Journal, 2023
We have measured line widths in active region coronal loops in order to determine whether the nonthermal broadening is anisotropic with respect to the magnetic field direction. These nonthermal velocities are caused by unresolved fluid motions.
Michael Hahn, Mahboubeh Asgari-Targhi, Daniel Wolf Savin   +2 more
doaj   +1 more source

Radio Measurements of the Magnetic Field in the Solar Chromosphere and the Corona

Frontiers in Astronomy and Space Sciences, 2021
The structure of the upper solar atmosphere, on all observable scales, is intimately governed by the magnetic field. The same holds for a variety of solar phenomena that constitute solar activity, from tiny transient brightening to huge Coronal Mass ...
Costas E. Alissandrakis, Dale E. Gary
doaj   +1 more source

On the Freeze‐In Distance of Solar Wind Fluid Entropy Variability in the Corona

Journal of Geophysical Research: Space Physics, Volume 131, Issue 3, March 2026.
Abstract The strong correlation between solar wind entropy and the frozen‐in ion charge state ratio O7+/O6+ ${\mathrm{O}}^{7+}/{\mathrm{O}}^{6+}$ indicates that entropy variability on timescales of hours or longer is preserved from its solar source. This prompts the question: where in the solar atmosphere does this entropy variability come from, and at
Aidan J. Nakhleh, Nicholeen M. Viall, Susan T. Lepri, Jim M. Raines   +3 more
wiley   +1 more source

The Effect of the Parametric Decay Instability on the Morphology of Coronal Type III Radio Bursts

The Astrophysical Journal Letters, 2023
The nonlinear evolution of Alfvén waves in the solar corona leads to the generation of Alfvénic turbulence. This description of the Alfvén waves involves parametric instabilities where the parent wave decays into slow mode waves giving rise to density ...
Chaitanya Prasad Sishtla, Immanuel Christopher Jebaraj, Jens Pomoell, Norbert Magyar, Marc Pulupa, Emilia Kilpua, Stuart D. Bale   +6 more
doaj   +1 more source

Relative Elemental Abundances of the Quiet Solar Corona as Determined by SERTS [PDF]

The Astrophysical Journal, 1997
Intensities of extreme-ultraviolet (EUV) spectral lines were measured as a function of radius off the solar limb by two flights (1989 May 5 and 1991 May 7) of the Solar Extreme-ultraviolet Rocket Telescope and Spectrograph (SERTS) for three quiet solar regions. The line-ratio density, line-ratio temperature, and emission measure were determined.
D. A. Falconer, J. M. Davila, R. J. Thomas   +2 more
openaire   +1 more source