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IUE low-resolution observations of the triple system CHCygni: the mass transfer in the symbiotic pair
Bode, M. F.; Drechsel, H.; Skopal, A. +1 more
We present and analyse UV low-resolution spectra of CHCyg taken during the whole period of the International Ultraviolet Explorer (IUE) mission. Our analysis of the variation in the UV/optical hot star continuum confirmed the basic scenario of sporadic accretion in the symbiotic pair of the triple-star system as being responsible for maintaining i…
Analysis Methods for Multi-Spacecraft Data. ISSI Scientific Reports Series SR-001, ESA/ISSI, Vol. 1. ISBN 1608-280X, 1998
Daly, Patrick W.; Paschmann, Götz
[\ion(C)(ii)] 158 and [\ion(O)(i)] 63 MU M ISO-Observations of L1457
Timmermann, Ralf; Koester, Benedikt; Stutzki, Juergen
We report here the results of [C Ii] 158 and [O I] 63 mu m fine-structure line observations along two cuts across a molecular clump of L1457 (MBM 12) carried out with ISO-LWS. [C Ii] emission was detected at all positions observed. It can be assigned to the cooling of the diffuse atomic interstellar medium. We observed excess [C Ii] emission from …
A Nearby Galaxy in the Deep-Ultraviolet: Voyager 2 Observations of M33 from Lyα to the Lyman Limit
Keel, William C.
Observations of high-redshift galaxies in the emitted-wavelength regime around Lyα have renewed interest in the appearance of normal galaxies in the deep ultraviolet. This paper presents an analysis of spectrophotometry of the local Sc galaxy Messier 33 (NGC 598) obtained by Voyager 2, covering the range from below the Lyman limit to about 1250 Å.…
Study of Neglected Variable Stars Classified as Type II Cepheids
Szabados, L.; Berdnikov, L. N.
Four variable stars classified as Type II Cepheids have been studied partly based on new photometry and the Hipparcos photometric data. The correct period is derived for V341 Ara and NW Pav and it is pointed out that RR Mic and V1711 Sgr do not belong to Type II Cepheids, instead they may be semi-regular variables. The cycle length of their variab…
Magnetic Fields in the Inner Heliosphere
Balogh, A.
The structure of Heliospheric Magnetic Field (HMF) is a function of both the coronal conditions from which it originates and dynamic processes which take place in the solar wind. The division between the inner and outer regions of the heliosphere is the result of dynamic processes which form large scale structures with increasing heliocentric dist…
Primordial Helium and DeltaY/DeltaZ from H II Regions and from Fine Structure in the Main Sequence Based on HIPPARCOS Parallaxes
Girardi, L.; Høg, E.; Pagel, B. E. J. +3 more
The primordial helium abundance YP is important for cosmology and the ratio DeltaY/DeltaZ of the changes relative to primordial abundances constrains models of stellar evolution. While the most accurate estimates of YP come from emission lines in extragalactic H II regions, they involve an extrapolation to zero metallicity which itself is closely …
Wide Field Planetary Camera 2 Observations of Proxima Centauri: No Evidence of the Possible Substellar Companion
Golimowski, David A.; Schroeder, Daniel J.
Two-epoch observations of Proxima Centauri using the Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC2) are reported. Exposures of 10 and 40 s were recorded through the F1042M filter (lambda_c ~ 1 µm), permitting examination of the circumstellar region beyond 0.09" from Proxima Cen. No evidence of a substellar companion withi…
No Death Star--For Now
Gould, Andrew; Frogel, Jay A.
A star passing within ~104 AU of the Sun would trigger a comet shower that would reach the inner solar system about 0.18 Myr later. We calculate an a priori probability of ~0.4% that a star has passed this close to the Sun but that the comet shower has not yet reached the Earth. We search the Hipparcos catalogue for such recent close-en…
Spectral Analysis
Eriksson, Anders I.