Search Publications
Missions
Journals
Publication Years
Can magnetopause reconnection drive Saturn's magnetosphere?
Coates, A. J.; Russell, C. T.; Dougherty, M. K. +3 more
While solar wind-driven compression of Saturn's magnetosphere is an important trigger of magnetospheric dynamics, the importance of magnetopause reconnection has been the subject of debate. Here we use Cassini observations at Saturn's magnetopause to address this open issue. Measured conditions at the boundary suggest a typical reconnection electr…
The soft X-ray spectrum of the luminous narrow line Seyfert galaxy PG 1211+143 - evidence for a second high-velocity outflow component
Pounds, K. A.
An XMM-Newton observation of the luminous Seyfert galaxy PG 1211+143 in 2001 revealed the first clear evidence for a highly ionized high-speed wind (in a non-broad absorption line active galactic nucleus), with a velocity of v ∼ 0.09c based on the identification of blueshifted absorption lines in both EPIC and Reflection Grating Spectrometer (RGS)…
Energization of planetary pickup ions in the solar system
Kallio, E.; Jarvinen, R.
We study the solar wind-induced ion escape from planetary atmospheres at different radial heliospheric distances in the solar system. We derive histograms of the gyroaveraged E×B velocities, energies, and Larmor radii of planetary ions in the solar wind at Mercury, Venus, Earth, and Mars. The statistical analysis is based on the interplanetary Pio…
Differential emission measure analysis of active region cores and quiet Sun for the non-Maxwellian κ-distributions
Dzifčáková, E.; Dudík, J.; Mackovjak, Š.
Context. The non-Maxwellian κ-distributions have been detected in the solar wind and can explain intensities of some transition region lines. Presence of such distributions in the outer layers of the solar atmosphere influences the ionization and excitation equilibrium and widens the line contribution functions. This behavior may be reflected on t…
Atmospheric parameters and carbon abundance for hot DB white dwarfs
Gänsicke, B. T.; Koester, D.; Provencal, J.
Atmospheric parameters for hot DB (helium atmosphere) white dwarfs near effective temperatures of 25 000 K are extremely difficult to determine from optical spectroscopy. The neutral He lines reach a maximum in this range and change very little with effective temperature and surface gravity. Moreover, an often unknown amount of hydrogen contaminat…
Mass Transport around Comets and its Impact on the Seasonal Differences in Water Production Rates
Altwegg, K.; Thomas, N.; Combi, M. R. +4 more
Comets are surrounded by a thin expanding atmosphere, and although the nucleus' gravity is small, some molecules and grains, possibly with the inclusion of ices, can get transported around the nucleus through scattering (atoms/molecules) and gravitational pull (grains). Based on the obliquity of the comet, it is also possible that volatile materia…
Long-Period Oscillations of Sunspots Observed by SOHO/MDI
Solov'ev, A. A.; Efremov, V. I.; Parfinenko, L. D. +1 more
We processed magnetograms that were obtained with the Michaelson Doppler Imager onboard the Solar and Heliospheric Observatory (SOHO/MDI). The results confirm the basic properties of long-period oscillations of sunspots that have previously been established and also reveal new properties. We show that the limiting (lowest) eigenmode of low-frequen…
Fresh exposures of hydrous Fe-bearing amorphous silicates on Mars
Weitz, Catherine M.; Bishop, Janice L.; Baker, Leslie L. +1 more
We have discovered relatively fresh exposures of a hydrated, amorphous material along the wall rock slopes in Coprates Chasma, Mars. Visible and near-infrared reflectance spectra extracted from the deposits exhibit broad absorptions around 1.42, 1.94, and 2.25 µm that are most consistent with laboratory spectra of nanophase hydrated Fe-rich alloph…
Structure and Dynamics of the Accretion Process and Wind in TW Hya
Strader, Jay; Cranmer, S. R.; Smith, Graeme H. +3 more
Time-domain spectroscopy of the classical accreting T Tauri star, TW Hya, covering a decade and spanning the far UV to the near-infrared spectral regions can identify the radiation sources, the atmospheric structure produced by accretion, and properties of the stellar wind. On timescales from days to years, substantial changes occur in emission li…
A quiescent galaxy at the position of the long GRB 050219A
Covino, S.; Pian, E.; D'Elia, V. +25 more
Context. Long-duration gamma-ray bursts (LGRBs) are produced by the collapse of very massive stars. Because of the short life time of their progenitors, LGRBs pinpoint star-forming galaxies. Recent studies demonstrate that LGRBs populate all types of star-forming galaxies from sub-luminous, blue compact dwarfs to luminous infrared galaxies.
A…