Results 61 to 70 of about 199 (138)

History of two mass loss processes in VY CMa. [PDF]

Proc Int Astron Union, 2023
Quintana-Lacaci G, Velilla L, Fonfría JP, Cernicharo J, Castro-Carrizo A, Agúndez M, Decin L.   +6 more
europepmc   +1 more source

High-time-cadence Spectroscopy and Photometry of Stellar Flares on M-dwarf YZ Canis Minoris with Seimei Telescope and TESS. II. Statistical Properties of Blue/Red Asymmetries in the Hα Line

The Astrophysical Journal
M-dwarfs frequently produce flares, and their associated coronal mass ejections (CMEs) may threaten the habitability of close-in exoplanets. M-dwarf flares sometimes show prominence eruption signatures, observed as blue/red asymmetries in the H α line ...
Yuto Kajikiya, Kosuke Namekata, Yuta Notsu, Kai Ikuta, Hiroyuki Maehara, Bunei Sato, Daisaku Nogami   +6 more
doaj   +1 more source

High-time-cadence Spectroscopy and Photometry of Stellar Flares on M dwarf YZ Canis Minoris with the Seimei Telescope and TESS. I. Discovery of Rapid and Short-duration Prominence Eruptions

The Astrophysical Journal
M dwarfs show frequent flares and associated coronal mass ejections (CMEs) may significantly impact close-in habitable planets. M dwarf flares sometimes show blue/red asymmetries in the H α line profile, suggesting prominence eruptions as an early stage ...
Yuto Kajikiya, Kosuke Namekata, Yuta Notsu, Hiroyuki Maehara, Bunei Sato, Daisaku Nogami   +5 more
doaj   +1 more source

Exo–IPM Scattering as a Hidden Gatekeeper of Narrowband Technosignatures

The Astrophysical Journal
Narrowband radio technosignatures can be significantly modulated by the host star’s exoplanetary interplanetary medium (Exo-IPM), where turbulence in stellar winds and coronal mass ejections (CMEs) imprint spectral broadening.
Vishal Gajjar, Grayce C. Brown
doaj   +1 more source

Extreme energetic particle events by superflare-asssociated CMEs from solar-like stars. [PDF]

Sci Adv, 2022
Hu J, Airapetian VS, Li G, Zank G, Jin M.   +4 more
europepmc   +1 more source

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