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Late-type giants with infrared excess. I. Lithium abundances
de Laverny, P.; Thévenin, F.; Jasniewicz, G. +1 more
de la Reza et al. (1997) suggested that all K giants become Li-rich for a short time. During this period the giants are associated with an expanding thin circumstellar shell supposedly triggered by an abrupt internal mixing mechanism resulting in the surface Li enrichment. In order to test this hypothesis twenty nine late-type giants with far-infr…
A new set of HST boron observations. I. Testing light elements stellar depletion
Primas, F.; Duncan, D. K.; Peterson, R. C. +1 more
A sample of 7 new stars ranging in metallicity from [Fe/H]=-2.0 to [Fe/H]=-0.75 has been analyzed in the boron spectral region. The spectra were observed with the Goddard High Resolution Spectrograph (GHRS) of the Hubble Space Telescope (HST). The targets were selected on the basis of their lithium and beryllium abundances in order to investigate …
Activity cycle and surface differential rotation of the single Pleiades star HD 82443 (DX Leo)
Lanza, A. F.; Messina, S.; Guinan, E. F. +1 more
The results of a long-term photometric monitoring of the young Pleiades moving group member HD 82443 are presented. A sequence of fifteen optical light curves obtained from 1989 to 1998 confirms the presence of a rotational modulation with a mean period of 5.377 days attributable to cool photospheric spots. The Maximum Entropy and the Tikhonov reg…
Strong optical line variability in MKN 110
Kollatschny, W.; Bischoff, K.
We present results of a long-term variability campaign on the Seyfert 1 galaxy Markarian 110. Mkn 110 is a narrow-line Seyfert 1 object hosted in a morphological peculiar galaxy. We monitored the optical continuum and the line intensities as well as their profiles over a time interval of nearly ten years. The continuum and the Balmer lines varied …
Strange velocities in the equatorial ejecta of eta Carinae
Humphreys, Roberta M.; Davidson, Kris; Ishibashi, Kazunori +3 more
We report HST/HRS observations of gas that appears to have been ejected in the equatorial zone of eta Carinae. Some of the observed emission lines are produced by Fe II fluorescence processes, which, for unknown reasons, are uniquely intense near eta Carinae. Surprisingly low velocities are found, most likely representing ejection events hundreds …
Lensed galaxies in Abell 370. I. Modeling the number counts and redshift distribution of background sources
Kneib, J. P.; Soucail, G.; Bézecourt, J. +1 more
We present new observations of the cluster-lens Abell 370: a deep HST/WFPC2 F675W image and ESO 3.6m spectroscopy of faint galaxies. These observations shed new light on the statistical properties of faint lensed galaxies. In particular, we spectroscopically confirm the multiple image nature of the B2-B3 gravitational pair (\cite{kneib93}), and de…
IUE observations of the high-velocity symbiotic star AG Draconis. III. A compendium of 17 years of UV monitoring, and comparison with optical and X-ray observations
Greiner, J.; González-Riestra, R.; Viotti, R. +1 more
We present the first extensive analysis of the ultraviolet observations with the IUE mission of the high velocity symbiotic system
The nature of strings in the nebula around eta Carinae
Weis, K.; Duschl, W. J.; Chu, Y. -H.
eta Carinae is one of the most extreme cases of a Luminous Blue Variable star. A bipolar nebula of 17('') size surrounds the central object. Even further out, a large amount of filamentary material extends to a distance of 30'' or about 0.3 pc. In this paper we present a detailed kinematic and morphological analysis of some outer filaments in this…
Detection of widely distributed UIR band emission in the disk of NGC 891
Lemke, D.; Lehtinen, K.; Mattila, K.
The spectrum of the unidentified infrared (UIR) emission bands between 5.9 and 11.7 mu m has been observed for the first time in the disk of an external galaxy. We have used the low-resolution spectrometer of the ISOPHOT instrument aboard ISO. The UIR bands at 6.2, 7.7, 8.6, and 11.3 mu m have absolute intensities which are similar to the values o…
Detection of the O VI 103.2 NM line polarization by the SUMER spectrometer on the SOHO spacecraft
Raouafi, N. -E.; Lemaire, P.; Sahal-Bréchot, S.
The first detection of the O VI 103.2 nm line polarization has been performed in the corona by SUMER (Solar Ultraviolet Measurements of Emitted Radiation) on the SOHO (Solar Heliospheric Observatory). The polarization properties of the spectrometer was used to analyze the solar radiation in a coronal hole at about 270 arcsec above the south solar …