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Common characteristics of CMEs and BLOBs: a new view of their possible origin
Eselevich, M. V.; Eselevich, V. G.
An analysis of the LASCO/SOHO data has shown that blobs are similar, in their basic characteristics, to CMEs, having a relatively small size and relatively low velocities. The formation of blobs and CMEs is usually accompanied by the process where a separate ray (or rays) of the streamer belt becomes occupied by additional anti-sunward traveling p…
Emission-Line Ratios for [N II] in Gaseous Nebulae and a Comparison between Theory and Observation
Feibelman, W. A.; Keenan, F. P.; Aller, L. H. +1 more
R-matrix calculations of electron impact excitation rates among the 2s22p2 3P, 1D, 1S, and 2s2p3 5S levels of N II are presented. These results are used in conjunction with other recent calculations of electron impact excitation rates and Einstein A-coefficients for N II …
Astrophysics in 2000
Aschwanden, Markus J.; Trimble, Virginia
It was a year in which some topics selected themselves as important through the sheer numbers of papers published. These include the connection(s) between galaxies with active central engines and galaxies with starbursts, the transition from asymptotic giant branch stars to white dwarfs, gamma-ray bursters, solar data from three major satellite mi…
Far-Ultraviolet Spectra of B Stars near the Ecliptic
Drake, Jeremy J.; Bowyer, Stuart; Edelstein, Jerry +7 more
Spectra of B stars in the wavelength range of 911-1100 Å have been obtained with the Espectrógrafo Ultravioleta de Radiación Difusa (EURD) spectrograph on board the Spanish satellite MINISAT-01 with ~5 Å spectral resolution. International Ultraviolet Explorer (IUE) spectra of the same stars have been used to normalize Kurucz models to the distance…
Analysis of HST and IUE Ultraviolet Spectra for T Tauri Stars: DF Tau
Vittone, A. A.; Errico, L.; Lamzin, S. A.
We analyze ultraviolet spectra of DF Tau, a binary system whose primary component is a classical T Tauri star. The spectra were obtained from the Hubble Space Telescope and the IUE satellite. The stellar emission in the wavelength range covered is shown to originate in an accretion shock wave. The gas infall velocity is 250 km/s. The accreted-gas …
The FERRUM project: Experimental f-values for 4p-5s transitions in Fe II
Lundberg, H.; Li, Z. S.; Johansson, S. +2 more
New measurements of radiative lifetimes of four 3d65s levels in Fe II at about 10 eV are presented along with absolute oscillator strengths for twenty 4p-5s transitions involving the four levels. The experimental measurements are compared with two different sets of theoretical calculations. The lines are of particular interest in the mo…
Pick-up ions upstream and downstream of the termination shock
Fahr, H. J.; Hilchenbach, M.; Czechowski, A. +1 more
Hydrogen pick-up ions produced in the inner heliosphere are convected outwards with the solar wind and suffer energy-diffusion by quasilinear wave-particle interactions. When arriving at the solar wind termination shock, the big majority of these pick-up's passes directly from the preshock to the postshock plasma regime. While crossing the shock t…
Atomic Physics with the Goddard High Resolution Spectrograph on the Hubble Space Telescope. V. Oscillator Strengths for Neutral Carbon Lines below 1200 Å
Federman, S. R.; Zsargó, J.
We analyzed high-resolution spectra of interstellar C I absorption toward λ Ori, 1 Sco, and δ Sco that were obtained with the Goddard High Resolution Spectrograph on the Hubble Space Telescope. Several multiplets were detected within the wavelength interval 1150-1200 Å, where most C I lines have ill-defined oscillator strength; multiplets at longe…
The Accretion Disk and White Dwarf in the Short-Period Dwarf Novae TY Piscium and V436 Centauri during Quiescence
Sion, Edward M.; Nadalin, Ira
The short-period dwarf novae TY Psc and V436 Cen are SU UMa systems with very similar orbital periods, similar recurrence times for normal outbursts (~23 days) and superoutbursts (~340 days), and nearly identical outburst amplitudes. We have carried out high-gravity model atmosphere and accretion disk synthetic spectra from the grid of Wade & …
Millimeter observations of radio-loud active galaxies
Bertoldi, F.; van Bemmel, I. M.
In order to study the nature of the far-infrared emission observed in radio-loud active galaxies, we have obtained 1.2 mm observations with the IRAM 30 m telescope for a sample of eight radio-loud active galaxies. In all objects we find that the 1.2 mm emission is dominated by non-thermal emission. An extrapolation of the non-thermal radio spectru…