Results 41 to 50 of about 15,079 (225)

Stellar Chromospheric Variability [PDF]

Universe, 2021
Cool stars with convective envelopes of spectral types F and later tend to exhibit magnetic activity throughout their atmospheres. The presence of strong and variable magnetic fields is evidenced by photospheric starspots, chromospheric plages and coronal flares, as well as by strong Ca ii H+K and Hα emission, combined with the presence of ultraviolet ...
Richard de Grijs, Devika Kamath
openaire   +2 more sources

Optical instrumentation for chromospheric monitoring during solar cycle 25 at Paris and Côte d’Azur observatories

Journal of Space Weather and Space Climate, 2020
We present the observing program proposed by Paris and Côte d’Azur Observatories for monitoring solar activity during the upcoming cycle 25 and providing near real time images and movies of the chromosphere for space-weather research and applications ...
Malherbe Jean-Marie, Corbard Thierry, Dalmasse Kevin   +2 more
doaj   +1 more source

The Role of Partial Ionization Effects in the Chromosphere

, 2015
The energy for the coronal heating must be provided from the convection zone. The amount and the method by which this energy is transferred into the corona depends on the properties of the lower atmosphere and the corona itself.
Carlsson, Mats, De Pontieu, Bart, Hansteen, Viggo H., Martinez-Sykora, Juan   +3 more
core   +1 more source

Stable umbral chromospheric structures [PDF]

Astronomy & Astrophysics, 2015
Accepted to Astronomy and Astrophysics.
Henriques, V. M. J., Scullion, E., Mathioudakis, M., Kiselman, D., Gallagher, P. T., Keenan, F. P.   +5 more
openaire   +4 more sources

Spatial and temporal variations of Ca II K line profile shapes in different structures of solar chromosphere. I. Features of individual profiles

Solar-Terrestrial Physics, 2018
We have studied Ca II K line profiles, using two time series of spectrograms taken in two regions near the solar disk center. In each of the regions, the spectrograph slit cut out several areas of the quiet region and a plage.
Turova I.P., Grigoryeva S.A., Ozhogina O.A.   +2 more
doaj   +1 more source

SPATIAL AND TEMPORAL VARIATIONS OF K Ca II LINE PROFILE SHAPES IN DIFFERENT STRUCTURES OF THE SOLAR CHROMOSPHERE. II. DETERMINATION TECHNIQUE AND CORRELATION RELATIONSHIPS BETWEEN THE K CA II LINE PARAMETERS FOR K₁ AND K₂ FEATURES

Solar-Terrestrial Physics, 2020
We have studied two regions located at the base of a coronal hole. For the K₁ intensity minima and K₂ peaks, which form between the upper photosphere and the lower chromosphere and in the lower chromosphere respectively, a number of Ca II line parameters
I.P. Turova, S.A. Grigoryeva, O.A. Ozhogina   +2 more
doaj   +1 more source

TeV Mini Black Hole Decay at Future Colliders [PDF]

, 2005
It is generally believed that mini black holes decay by emitting elementary particles with a black body energy spectrum. The original calculation lead to the conclusion that about the 90% of the black hole mass is radiated away in the form of photons ...
Alex Casanova, Banks T Fischler W, Cavaglia M, Cornell A S Naylor W Sasaki M, Euro Spallucci, Fontanini M Spallucci E Padmanabhan T, Harris C M, Harris C M, Harris C M, Hawking S W, Hewett J L Lillie B Rizzo T G, Hossenfelder S, Hossenfelder S Koch B Bleicher M, Jauch J M, Koch B, Landsberg G, Misner C W, Nicolini P, Nicolini P Smailagic A Spallucci E, Nicolini P Smailagic A Spallucci E, Sjöstrand T Lönnblad L Mrenna S Skands P, Spallucci E, Thorne K S   +22 more
core   +2 more sources

Why “Solar Tsunamis” Rarely Leave Their Imprints in the Chromosphere

The Astrophysical Journal Letters, 2023
Solar coronal waves frequently appear as bright disturbances that propagate globally from the eruption center in the solar atmosphere, just like the tsunamis in the ocean on Earth.
Ruisheng Zheng, Yihan Liu, Wenlong Liu, Bing Wang, Zhenyong Hou, Shiwei Feng, Xiangliang Kong, Zhenghua Huang, Hongqiang Song, Hui Tian, Pengfei Chen, Robertus Erdélyi, Yao Chen   +12 more
doaj   +1 more source

Three-dimensional magnetic structure of a sunspot: comparison of the photosphere and upper chromosphere

, 2017
We investigate the magnetic field of a sunspot in the upper chromosphere and compare it to the field's photospheric properties. We observed the main leading sunspot of the active region NOAA 11124 on two days with the Tenrife Infrared Polarimeter-2 (TIP ...
Hirzberger, Johann, Joshi, Jayant, Lagg, Andreas, Solanki, Sami K.   +3 more
core   +1 more source

Chromosphere of K giant stars Geometrical extent and spatial structure detection

, 2011
We aim to constrain the geometrical extent of the chromosphere of non-binary K giant stars and detect any spatial structures in the chromosphere. We performed observations with the CHARA interferometer and the VEGA beam combiner at optical wavelengths ...
A. Spang, Andretta, Ayres, B. Pichon, Baines, Berio, Bonneau, Brown, Busà, C. Farrington, Carpenter, Chen, Claret, Cuntz, Cuntz, D. Bonneau, D. Mourard, di Benedetto, Diaz-Cordoves, Dyck, Eaton, Eriksson, F. Thévenin, Gustafsson, H. McAlister, Hall, Houdashelt, I. Tallon-Bosc, J. M. Clausse, J. Sturmann, Judge, K. Perraut, Kovacs, L. Sturmann, Linsky, Luck, Massarotti, McWilliam, Meilland, Montes, Morel, Mourard, Mozurkewich, N. Nardetto, N. Turner, O. Chesneau, O. Delaa, P. Berio, P. J. Goldfinger, P. Stee, Perryman, Pietrinferni, R. Ligi, Reimers, Richichi, Simon, Skrutskie, T. Merle, T. ten Brummelaar, ten Brummelaar, van Belle, van Leeuwen, White   +62 more
core   +3 more sources