Results 81 to 90 of about 1,774 (127)

The helium chromosphere, coronal holes, and stellar X-rays

The Astrophysical Journal, 1975
The solar chromosphere at the limb seen in D3 is an irregular bright band 1000 km thick with a dark band 1000 km thick beneath. The D3 chromosphere disappears in coronal holes. It is shown that the D3 emission, as well as the other He I and He II lines, can be explained quantitatively by photoionization by coronal back-radiation. A Chapman layer with N(
openaire   +1 more source

Measuring the magnetic fields in the chromospheres of low-mass stars. [PDF]

Nat Commun
Cang T, Petit P, Donati JF, Tian H, Fu J, Li H, Bellotti S, Hu X, Ma X, Lopez Ariste A, Xing K, Morin J, Lu H, Zong W.   +13 more
europepmc   +2 more sources

The Impact of Dust/Gas Ratios on Chromospheric Activity in Red Giant and Supergiant Stars. [PDF]

Proc Int Astron Union, 2018
Carpenter KG, Rau G.
europepmc   +1 more source

Combined ultraviolet studies of astronomical sources [PDF]

Ultraviolet studies of astronomical sources are discussed. Some studies utilized IVE data. Non-radiative shock at the edge of the Cygnses Loop, stellar flares, local interestellar medium, hot galaxies, stellar mass ejection, contact binaries, double ...
Dupree, A. K., Giampapa, M. S., Hartmann, L. W., Huchra, J. P., Noyes, R. W., Raymond, J. C.   +5 more
core   +1 more source

Stellar activity and coronal heating: an overview of recent results. [PDF]

Philos Trans A Math Phys Eng Sci, 2015
Testa P, Saar SH, Drake JJ.
europepmc   +1 more source

Further observations of the lambda 10830 He line in stars and their significance as a measure of stellar activity [PDF]

Measurements of the lambda 1030 He line in 198 stars are given along with data on other features in that spectral range. Nearly 80% of all G and K stars show some lambda 10830; of these, half are variable and 1/4 show emission.
Zirin, H.
core   +1 more source

Potential biosignatures in super-Earth atmospheres II. Photochemical responses. [PDF]

Astrobiology, 2013
Grenfell JL, Gebauer S, Godolt M, Palczynski K, Rauer H, Stock J, von Paris P, Lehmann R, Selsis F.   +8 more
europepmc   +1 more source

Astrospheres and Solar-like Stellar Winds. [PDF]

Living Rev Sol Phys, 2004
Wood BE.
europepmc   +1 more source

Asymmetry in zeta Auriage chromospheres [PDF]

Asymmetry in the ultraviolet spectra of zeta-Aur, similar to that reported in optical observations, was studied using IUE data. A plot of the integrated flux of zeta Aurigae from 1625 to 1675 A as a function of absolute phase shows no significant ...
Ahmad, I. A.
core   +1 more source

Beam electrons as a source of Hα flare ribbons. [PDF]

Nat Commun, 2017
Druett M, Scullion E, Zharkova V, Matthews S, Zharkov S, Rouppe Van der Voort L.   +5 more
europepmc   +1 more source