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Kinematics of nearby Subdwarfs

Wielen, R.; Jahreiss, H.; Fuchs, B.

A sample of subdwarfs with accurate space velocities and standarized metallicities is presented. This was constructed by combining Hipparcos parallaxes and proper motions with radial velocities and metallicities from Carney et al. (1994; CLLA). The accurate Hipparcos parallaxes lead to an – upward – correction factor of 11% of the photometric dist…

Young and Old Galaxies at High Redshift

Windhorst, R.; Waddington, I.; Cohen, S. +2 more

We review the results from recent deep HST imaging on faint galaxies. Artificial Neural Networks (ANNs) were used to classify faint galaxies based on surface brightness and light profiles. We use available UV + ground-basedU-band images of nearby galaxies to address the effects from the uncertain red shifted UV-morphology on the classifications, r…

The Wilson-Bappu relation for RS CVn stars

Doyle, J. G.; Özeren, F. F.; Jevremovic, D.

We investigate the extent to which the Wilson-Bappu relationship holds for chromospherically active binaries using the Mg ii h&k lines of 41 RS CVn stars observed with IUE. The resulting fits are different from the relationships obtained for single, less active stars. The parallax used were those from the hipparcos catalogue, these give a much…

The IUE Spectra of the O VI Sequence Planetary Nebulae NGC 2452, NGC 7026, M3-30, and Lo 4

Feibelman, Walter A.

We present emission-line fluxes for NGC 2452, NGC 7026, M3-30, and Lo 4 from IUE low-dispersion spectra that have been processed by the New Spectral Image Processing System (NEWSIPS). For NGC 2452, a terminal wind velocity of -4200+/-300 km s^-1 was determined from the C IV λ1549 P Cygni profile, while that of NGC 7026 is -4600+/-300 km …

New Orbital Elements of 5 Interferometric Double Stars

Olevic, D.; Jovanovic, P.

In this paper, for the first time, are presented elliptical and Thiel-Innes orbitatal elements for the following interferometric pairs: WDS 00416+2438 = WRH, WDS 03271+1845 = CHARA 10, WDS 04044+2406 = McA 13 Aa, WDS 17095+4047 = McA 45 and WDS 23019+4219 = o And Aa. For the pairs WDS 03271+1845 = CHARA 10 and WDS 04044+2406 = McA 13 Aa are calcul…

Coronal Heating: a Comparison of Ion-cyclotron and Gravity Damping Models

Poletto, G.; Cuseri, I.; Mullan, D.

SOHO/UVCS data indicate that minor ions in the corona are heated more than hydrogen, and that coronal heating results in T_⊥ larger than T_‖. Analogous behavior has been known from in situ measurements in solar wind for many years. Here we compare and contrast two mechanisms which have been proposed to account for the above beh…

Correction to “The interplanetary events of January-May, 1997 as inferred from energetic particle data, and their relationship with solar events”

St. Cyr, O. C.; Cane, H. V.; Richardson, I. G.

Electron temperature diagnostics for the quiet Sun using SI BT IV lines

Curdt, W.; Mathioudakis, M.; Keenan, F. P. +3 more

We compare SUMER observations of six Si riptsize IV emission lines detected at the quiet Sun disk centre with recent theoretical line ratio calculations. Good agreement is found between theory and observation for ratios involving the 1394, 1403 and 818 Ä line intensities. This agreement supports the theoretical prediction that the temperature wher…

The role of stars in the energetics of LINERs

Maoz, Dan

Imaging studies have shown that ~ 25% of LINER galaxies display a compact nuclear UV source. I compare the HST ultraviolet (1150-3200 Å) spectra that are now available for seven such ``UV-bright'' LINERs. The spectra of NGC 404, NGC 4569, and NGC 5055 show clear absorption-line signatures of massive stars, indicating a stellar origin for the UV co…

Is LkHα 264 like a young, extremely active Sun?

Gameiro, J. F.; Costa, V. M.; Lago, M. T. V. T.

We combine calibrated International Ultraviolet Explorer (IUE) archive data and new low-resolution optical data for the T Tauri star LkHα 264 covering the region from 1200 to 7000Å. The UV continuum is well fitted by the combination of a blackbody at 4300K plus hydrogenic free-free and free-bound emission from a dense plasma at 3.5x10^4K plus the …