Solar chromosphere and photosphere, as well solar atmospheric structures, such prominences spicules, are made of partially ionized plasmas. Observations have reported the presence damped or amplified oscillations in these plasmas, which been interpreted terms magnetohydrodynamic (MHD) waves. Slow magnetoacoustic waves could be responsible for oscillations. The present study investigates tempora...

New measurements of C/C ratios in Galactic molecular clouds have been conducted using the N 1⁄4 1 ! 0 transition of the CN radical. This species is unique in that it has extensive hyperfine structure that can be accurately used to correct for line saturation effects. Combined with the past observations of Savage and coworkers, the ratios derived from CN are the most extensive data set to date f...

Abstract We report a series of numerical experiments for the propagation momentum pulse representing chromospheric jet, simulated using an idealized magnetohydrodynamic model. The jet in stratified lower solar atmosphere is subjected to varied initial driver (amplitude, period) and magnetic field conditions examine parameter influence over morphology kinematics. captured key observed spicule ch...

Observation of the solar atmosphere reveals a wide range of motions, from small scale jets and spicules to global-scale coronal mass ejections. Identifying and characterizing these motions are essential to advancing our understanding the drivers of space weather. Both automated and visual identifications are currently used in identifying CMEs. To date, eruptions near the solar surface (which ma...

We compare the H I column densities from Lyα absorption to the metal column densities from X-ray absorption in γ-ray burst (GRB) afterglows. Eight bursts of seventeen entering the sample, have significant extragalactic X-ray absorptions. Of these we find a range in metallicities from sub-solar to a few hundred times the solar value. There is a complete lack of correlation between the X-ray and ...

We study H I Lyα absorption observed by the Hubble Space Telescope toward the nearby binary system α Cen (G2 V+K0 V) and its distant companion star Proxima Cen (M5.5 Ve). Absorption from heliospheric H I heated by the solar wind/ISM interaction is observed toward both α Cen and Proxima Cen. Absorption from analogous “astrospheric” material surrounding the stars is detected toward α Cen, but not...

We present a search for infrared dust emission associated with the Leo cloud, a large intergalactic cloud in the M96 group. Mid-infrared and far-infrared images were obtained with IRAC and MIPS on the Spitzer Space Telescope. Our analysis of these maps is done at each wavelength relative to the Hi spatial distribution. We observe a probable detection at 8 μm and a marginal detection at 24μm ass...