Results 91 to 100 of about 334 (164)

FUMES. IV. Optical and Far-ultraviolet Spectra of a Flare on the M Dwarf GJ 4334

The Astronomical Journal
On 2017 September 20, we observed GJ 4334, an M5V dwarf rotating with a period of 23.5 days, simultaneously with both the Space Telescope Imaging Spectrograph aboard Hubble (1160–1710 Å) and the Dual Imaging Spectrograph mounted on the 3.5 m telescope at
Girish M. Duvvuri, J. Sebastian Pineda, Aylin García Soto, Zachory K. Berta-Thompson, Allison Youngblood, Kevin France, Elisabeth R. Newton, Keivan G. Stassun   +7 more
doaj   +1 more source

Partially Coherent Scattering in Stellar Chromospheres. V. Analytic Approximations Including Background Continuum Absorption [PDF]

, 2002
K. G. Gayley
openalex   +1 more source

Potential Chromospheric Evaporation in the M Dwarf’s Flare Triggered by Einstein Probe Mission

The Astronomical Journal
Although flares from late-type main-sequence stars have been frequently detected in the multiwavelength, the associated dynamical process has been rarely reported so far.
J. Wang, X. Mao, C. Gao, H. Y. Liu, H. L. Li, H. W. Pan, C. Wu, Y. Liu, G. W. Li, L. P. Xin, S. Jin, D. W. Xu, E. W. Liang, W. M. Yuan, J. Y. Wei   +14 more
doaj   +1 more source

First Direct Detection of Magnetic Fields in Starspots and Stellar Chromospheres [PDF]

, 2007
S. V. Berdyugina, D. M. Fluri, N. Afram, F. Suwald, P. Petit, J. Arnaud, David M. Harrington, J. R. Kuhn   +7 more
openalex   +1 more source

Heating of Solar and Stellar Chromospheres and Coronae by MHD Waves [PDF]

, 1992
Z. E. Musielak
openalex   +1 more source

Mind the Gap. II. The Near-UV Fluxes of M Dwarfs

The Astronomical Journal
Because of the continuous variations in mass, metallicity, and opacity, dwarf stars are distributed along the main sequence on optical and near-IR color–magnitude diagrams following a smooth polynomial.
Wei-Chun Jao, Allison Youngblood
doaj   +1 more source

Observation and modelling of main-sequence stellar chromospheres - VII. Rotation and metallicity of dM1 stars^★ [PDF]

, 2008
E. R. Houdebine
openalex   +1 more source

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

Stellar Library of Differential Emission Measures and Extreme Ultraviolet Spectra: Dwarf Stars Observed by the Extreme Ultraviolet Explorer

The Astrophysical Journal
Extreme ultraviolet (EUV; 100–912 Å) photons influence the formation and evolution of planets by ionizing hydrogen and other species, but the EUV radiation of most exoplanet host stars is poorly constrained.
Girish M. Duvvuri, Zachory K. Berta-Thompson, J. Sebastian Pineda, Kevin France, Alexander Brown, Allison Youngblood, David J. Wilson, Cynthia S. Froning, P. Christian Schneider, Thomas Ayres, Keivan G. Stassun   +10 more
doaj   +1 more source

HST Observations of HD 166620 and τ Ceti: First UV Spectra of a Magnetic Grand Minimum Star and the Extent of τ Ceti’s Astrosphere

The Astrophysical Journal
We present new Hubble Space Telescope (HST) UV spectra of the K2 V star HD 166620, the first star clearly recognized to be in a “magnetic grand minimum” state analogous to the Sun’s “Maunder minimum” in the late 1600s. The stellar H I Ly α surface fluxes
Brian E. Wood, Hans-Reinhard Müller, Dean Hartshorn, Seth Redfield, Travis S. Metcalfe   +4 more
doaj   +1 more source