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The JPL Extragalactic Radio Reference Frame: Astrometric Results of 1978-96 Deep Space Network VLBI

Naudet, C. J.; Sovers, O. J.; Coker, R. F. +2 more

Celestial reference frames determined from measurements of extragalactic radio sources are used in interplanetary navigation, Earth orientation measurements, geodesy, and astrometry. The JPL 1997-3 celestial reference frame is derived from very long baseline interferometric (VLBI) measurements of 291 compact extragalactic radio sources. The observ…

Analysis of Infrared Spectra of Carbon Stars Observed by the ISO SWS

Ohnaka, K.; Yamamura, I.; Tsuji, T. +1 more

Blue Compact Galaxies at Redshifts Z=0.2-1.3

Guzmán, R.

We study the nature of faint blue compact galaxies (BCGs) at redshifts z ∼ 0.2 - 1.3 using Keck and HST. Despite being very luminous (L_B ∼ L^*), most distant BCGs have masses M ∼ 10¹⁰M_⊙, i.e., they are dwarf stellar systems. The majority of these galaxies have colors, sizes, surface brightnesses, luminosi…

Galactic Evolution of the Light Elements: A New Set of B Observations

Primas, F.

The boron 2500 Angstroms spectral region has been observed with the Goddard High Resolution Spectrograph (GHRS) of the Hubble Space Telescope (HST) in a new set of metal-poor stars and analyzed by spectrum synthesis technique, adopting the most recent model atmospheres. By taking into account the Li and Be abundances available from the literature …

HST observations of GRO J1655/-40 in outburst

Hynes, Robert I.

We examine the results of a coordinated HST-RXTE-CGRO campaign to study the microquasar GRO J1655-40 during its 1996-7 outburst, focusing on interpretation of the overall anti-correlation seen between optical and X-ray fluxes during the early months of the outburst. Our tools include echo-mapping, optical/UV continuum spectral modelling and analys…

Kinematic Substructure of Halo Stars from HIPPARCOS Observations

Chen, B.

In the Letter ``Kinematic Substructure of Halo Stars from Hipparcos Observations'' by B. Chen (ApJ, 495, L1 [1998]), the color-magnitude diagram in Figure 6 is plotted upside down. Thus, most stars in the sample are halo main-sequence stars. Other results and the conclusion of the Letter are not affected.

Interstellar C IV and SI IV in the Direction of Loop I

Freire Ferrero, R.

Nearby late-B and early-A stars show clear IS absorptions in Mg II, C II and other lines (IUE spectra). Some of them, in the Sco Cen direction, also show absorption features at C IV and Si IV line wavelengths. We discuss the possible formation of these lines in an intermediate temperature gas region between the dense and cold H I wall and the hot …

Evolution and Mass Loss of AGB Stars in the Small Magellanic Cloud

Waters, L. B. F. M.; Blommaert, J. A. D. L.; van Loon, J. Th. +7 more

Clues to the Evolution of Massive Stars from their Far-Infrared Environments

Marston, A. P.

The turbulent state of cometary ion pickup generated fluctuations near comet P/Halley

Krauklis, I.; Johnstone, A. D.

One of the principal effects of an outgassing comet is to introduce additional mass into the solar wind flow. This mass-loading process results in the generation of Alfvén waves via ion-cyclotron resonance. In the case of the Halley encounter this source of ``new'' fluctuations was introduced into a low speed solar wind 0.89 AU from the sun. Previ…