Results 71 to 80 of about 220 (141)

Universal Constants in Self-organized Criticality Systems

The Astrophysical Journal
The occurrence frequency distributions of fluxes ( F ) and fluences or energies ( E ) observed in the majority (in 18 out of 23 cases) of astrophysical phenomena are found to be consistent with the predictions of the fractal-diffusive self-organized ...
Markus J. Aschwanden
doaj   +1 more source

First Detection of an Ultracool Dwarf at 340 MHz: VLITE Observations of EI Cancri AB

The Astronomical Journal
Magnetically driven phenomena such as flaring events and aurorae lead ultracool dwarfs (UCDs) to emit at radio frequencies. Despite decades of scrutiny, a comprehensive physical understanding of their radio emission at different frequencies remains ...
Michele L. Silverstein, Tracy E. Clarke, Wendy M. Peters, Emil Polisensky, Jackie Villadsen, Jordan M. Stone   +5 more
doaj   +1 more source

Solar Particle Acceleration

Astronomy
High-energy particles may be accelerated widely in stellar coronae; probably by the same processes we find in the Sun. Here, we have learned of two physical mechanisms that dominate the acceleration of solar energetic particles (SEPs).
Donald V. Reames
doaj   +1 more source

Do Young Suns Produce Frequent, Massive CMEs? Results from Five-year Dedicated Optical Observations of EK Draconis and V889 Hercules

The Astrophysical Journal
We report results from a five-year (132-night) dedicated observational campaign targeting two nearby young solar-type stars, EK Draconis (∼50–125 Myr age) and V889 Hercules (∼30 Myr age), using the 3.8 m Seimei Telescope and Transiting Exoplanet Survey ...
Kosuke Namekata, Hiroyuki Maehara, Yuta Notsu, Satoshi Honda, Kai Ikuta, Daisaku Nogami, Kazunari Shibata   +6 more
doaj   +1 more source

Apache Point Observatory (APO)/SMARTS Flare Star Campaign Observations. I. Blue Wing Asymmetries in Chromospheric Lines during Mid-M-Dwarf Flares from Simultaneous Spectroscopic and Photometric Observation Data

The Astrophysical Journal
We conducted the time-resolved simultaneous optical spectroscopic and photometric observations of mid-M-dwarf flare stars YZ CMi, EV Lac, and AD Leo. Spectroscopic observations were obtained using Apache Point Observatory 3.5 m and Small and Moderate ...
Yuta Notsu, Adam F. Kowalski, Hiroyuki Maehara, Kosuke Namekata, Kenji Hamaguchi, Teruaki Enoto, Isaiah I. Tristan, Suzanne L. Hawley, James R. A. Davenport, Satoshi Honda, Kai Ikuta, Shun Inoue, Keiichi Namizaki, Daisaku Nogami, Kazunari Shibata   +14 more
doaj   +1 more source

Formation of Amino Acids and Carboxylic Acids in Weakly Reducing Planetary Atmospheres by Solar Energetic Particles from the Young Sun. [PDF]

Life (Basel), 2023
Kobayashi K, Ise JI, Aoki R, Kinoshita M, Naito K, Udo T, Kunwar B, Takahashi JI, Shibata H, Mita H, Fukuda H, Oguri Y, Kawamura K, Kebukawa Y, Airapetian VS.   +14 more
europepmc   +1 more source

Multiwavelength Campaign Observations of a Young Solar-type Star, EK Draconis. II. Understanding Prominence Eruption through Data-driven Modeling and Observed Magnetic Environment

The Astrophysical Journal
EK Draconis, a nearby young solar-type star (G1.5V, 50–120 Myr), is known as one of the best proxies for inferring the environmental conditions of the young Sun.
Kosuke Namekata, Kai Ikuta, Pascal Petit, Vladimir S. Airapetian, Aline A. Vidotto, Petr Heinzel, Jiří Wollmann, Hiroyuki Maehara, Yuta Notsu, Shun Inoue, Stephen Marsden, Julien Morin, Sandra V. Jeffers, Coralie Neiner, Rishi R. Paudel, Antoaneta A. Avramova-Boncheva, Keith Gendreau, Kazunari Shibata   +17 more
doaj   +1 more source

Effects of Transient Stellar Emissions on Planetary Climates of Tidally Locked Exo-Earths

The Astronomical Journal
Space weather events in exoplanetary environments sourced from transient host star emissions, including stellar flares, coronal mass ejections, and stellar proton events, can substantially influence a planet's habitability and atmospheric evolution ...
Howard Chen, Paolo De Luca, Assaf Hochman, Thaddeus D. Komacek   +3 more
doaj   +1 more source

Assessing natural global catastrophic risks. [PDF]

Nat Hazards (Dordr), 2023
Baum SD.
europepmc   +1 more source

The evolution of the solar wind. [PDF]

Living Rev Sol Phys, 2021
Vidotto AA.
europepmc   +1 more source