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Warm molecular envelope of M giants and Miras: a new molecule forming region unmasked by the ISO SWS.

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

Our observations with the ISO SWS revealed that H_2_O band at 2.7µm appears as absorption already in an M2 giant β Peg and strengthens towards later M giants. Further, CO_2_ 4.2µm band appears as absorption in an M7 giant SW Vir and especially strong in a Mira variable S Vir. The excitation temperatures of these molecular bands estimat…

The TYCHO Catalogue

Makarov, V. V.; Bastian, U.; Fabricius, C. +9 more

The principal observational characteristics of the Tycho Catalogue, and a summary of its main astrometric and photometric properties, are presented. Median astrometric standard errors (in position, parallax, and annual proper motion) are typically around 7mas for stars brighter than V_T_~9mag, and approximately 25mas for V_T_~10.5mag, at the catal…

Composition of Interstellar Clouds in the Disk and Halo. IV. HD 215733

Fitzpatrick, Edward L.; Spitzer, Lyman, Jr.

In this paper we continue our investigation of diffuse clouds in the interstellar medium with an analysis of the line of sight toward the star HD 215733, located in the Galactic halo some 1700 pc below the plane. As in our previous papers, we utilize the component-fitting technique to determine velocities, velocity widths, and column densities for…

Discovery of Interstellar Hydrogen Fluoride 1

Neufeld, David A.; Phillips, Thomas G.; Schilke, Peter +1 more

We report the first detection of interstellar hydrogen fluoride. Using the Long Wavelength Spectrometer of the Infrared Space Observatory (ISO), we have detected the 121.6973 µm J=2-1 line of HF in absorption toward the far-infrared continuum source Sagittarius B2. The detection is statistically significant at the 13 σ level. On the basis of…

β Pictoris revisited by Hipparcos. Star properties.

Crifo, F.; Ferlet, R.; Vidal-Madjar, A. +2 more

Observations with the Hipparcos satellite allowed a new determination of the β Pictoris distance. This star is located at 19.28+/-0.19pc, a value close to the upper limit of previous evaluations. The overall consequences are briefly discussed; in particular it is concluded that in the frame of standard stellar evolution models, there is no need fo…

The Cluster Spatio-Temporal Analysis of Field Fluctuations (STAFF) Experiment

de Conchy, Y.; Parrot, M.; Rezeau, L. +20 more

Detection of ozone on Saturn's satellites RHEA and Dione

Johnson, R. E.; Cruikshank, D. P.; Pendleton, Y. J. +2 more

The satellites Rhea and Dione orbit within the magnetosphere of Saturn, where they are exposed to particle irradiation from trapped ions. A similar situation applies to the galilean moons Europa, Ganymede and Callisto, which reside within Jupiter's radiation belts. All of these satellites have surfaces rich in water ice. Laboratory studies of the …

Luminosities of SX Phoenicis, Large-Amplitude Delta Scuti, and RR Lyrae Stars

McNamara, D.

Strömgren _uvbyβ photometry of SX Phoenicis and large-amplitude δ Scuti variables is analyzed to determine the mean temperatures, metal abundances, and surface gravities of the stars. The mean temperatures and fundamental periods are used in conjunction with the pulsation equation and stellar models to derive masses, radii, surface gravities, and …

The Evolution of Galactic Boron and the Production Site of the Light Elements

Deliyannis, Constantine P.; Primas, F.; Rebull, L. M. +5 more

The Goddard High Resolution Spectrograph (GHRS) of the Hubble Space Telescope (HST) has been used to obtain spectra of the 2500 Å region in eight stars with metallicities ranging from [Fe/H] = -0.4 to -3.0, including the most metal-poor star ever observed for boron. Spectrum synthesis utilizing latest Kurucz model atmospheres has been used to dete…

Anomalously small magnetic field in the local interstellar cloud

Gloeckler, George; Geiss, Johannes; Fisk, L. A.

The solar wind carves out a cavity, known as the heliosphere, in the warm local interstellar cloud, which is itself embedded in a larger hot cloud. It is generally assumed that there is an overall pressure balance between these three regions. Thermal pressure and magnetic field pressure in the local interstellar cloud should therefore balance the …