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Hubble Space Telescope Spectroscopy of the Dwarf Nova RX Andromedae during Outburst Rise and Decline
Szkody, Paula; Sion, Edward M.; Gänsicke, Boris T. +1 more
We obtained Hubble Space Telescope far-ultraviolet spectra of the Z Cam-type dwarf nova RX And during the early rise to outburst and the decline from the same outburst. The spectral wavelength range covered was 1149-1435 Å. The rise spectrum is dominated by strong, very broad absorption lines, while the decline spectrum has strong, narrower absorp…
CCD photometric search for peculiar stars in open clusters. IV. Collinder 272, Pismis 20, Lyng\aa 14, NGC 6396 and NGC 6611
Paunzen, E.; Maitzen, H. M.; Pintado, O. I.
The time scale on which chemical peculiarity in upper main sequence stars begins is unknown. Results from the Hipparcos measurements indicate that the classical chemically peculiar (CP) stars occupy the whole area from the zero age main sequence to the terminal age main sequence (Gómez et al. \cite{Gom98}). However, Hubrig et al. (\cite{Hub00}) re…
The enigmatic WR46: A binary or a pulsator in disguise. I. The photometry
Sterken, C.; van der Hucht, K. A.; van Genderen, A. M. +3 more
We discuss the observational history of the Wolf-Rayet object WR 46 (WN3p), including a re-investigation of the original discovery plates from early this century. We find that the reported presence of N Iii lines is a mis-interpretation of N V lines and conclude that the object did not change its spectral type since the first recording one century…
The Front-to-Back Asymmetry of Coronal Emission
Andrews, M. D.
Several recent papers have considered the observation of halo coronal mass ejections (CMEs) using the assumption that coronal emission is symmetric with respect to angular position from the Sun. This paper presents a simple but rigorous treatment of the observation of a single electron in the solar corona. The brightness of an electron as a functi…
Dark matter revealed. More evidence from faint-star proper-motions for a cool and warm component of the local dark matter in the Galaxy
Méndez, R. A.
We present new evidence, based on faint HST proper-motions, for a bi-modal kinematic population of old white dwarfs, representative of the Thick-Disk and Halo of our Galaxy. This evidence supports the idea of a massive Halo comprised of faint and old white dwarfs, along with an extant population of Thick-Disk white dwarfs. We show how most of the …
Spectrophotometry of speckle binary stars
Al-Wardat, M. A.
Spectrophotometric observations of 20 speckle interferometric binary stars in the wavelength range 3640-8340 Å, with a resolution of 18 Å, are presented in the form of the measured flux corrected for atmospheric extinction in the units of erg/cm2\cdot s \cdot Å, with no corrections for interstellar reddening. B,V, and R magnitudes, B-V …
The pulsation modes and masses of carbon-rich long period variables
Bergeat, J.; Knapik, A.; Rutily, B.
Following our study of the carbon-rich giants in the HR diagram and of their luminosity function (Paper III), we investigate the pulsation data of the long period variables (LPVs) included in our sample. Pulsation modes (fundamental, overtone(s)) for carbon LPVs are identified in the period-radius diagram, making use of observed bi-periodicity in …
Optical and infrared observations of radioactive elements in supernovae
Sollerman, Jesper
At late phases the powering of supernova light curves is often provided by the decay of radioactive elements synthesized in the explosions. This is unambiguously revealed when the light curve decline follows the half-life time of the decaying elements, and the bolometric luminosity then directly provides the mass of ejected radioactive material. I…
A Hyper Extremely Red Object in the Field near 53W002
Tanaka, Ichi; Im, Myungshin; Yamada, Toru +1 more
Hyper extremely red objects (HEROs) are objects that are very red in near-IR colors (J-K>~3). They are speculated to be intrinsically red galaxies at z>~2 or Lyman break galaxies at z>10. We report the discovery of a HERO in the field that includes a known radio galaxy, 53W002, and a possible cluster of galaxies both at z=2.39. The HERO, …
Far-Ultraviolet Observations of Comet 2P/Encke at Perihelion
Raymond, J. C.; Wu, R.; Gardner, L. +6 more
Comet 2P/Encke was observed with UVCS/SOHO near perihelion (2000 September 9 and 11) in the Lyman lines of hydrogen. We present a Lyα image reconstructed from a series of long-slit spectra, along with the intensity ratios of Lyα, Lyβ, and Lyγ. The narrow Lyα profile indicates that the observed photons are scattered from hydrogen atoms produced by …