Search Publications
Reprocessed UV pulses from the binary companions of X-ray pulsars
Dolan, J. F.; Boyd, P. T.; Percival, J. W. +3 more
A search for reprocessed X-rays causing UV pulsations in the companion stars to X-ray pulsars was carried out in a 200 Angstroms wide bandpass centered at 1450 Angstroms using the High Speed Photometer on the Hubble Space Telescope. We observed the systems A0535+26 = HD245770, 4U0900-40 (Vela XR-1) = HD77581, A1118-61 = He3-640, and 4U1145-619 = H…
Mid-infrared spectroscopy of obscured IRAS galaxies
Taniguchi, Yoshiaki; Sato, Yasunori; Kawara, Kimiaki +1 more
Spectra from 6 to 12 mu m are presented for the infrared galaxies NGC 1266, Arp 148, and IRAS 1713+53. Though they are not markedly luminous (<= 10(12) L_⊙), their IRAS colors are close to the colors of ultraluminous infrared galaxies, and thus indicative of heavy obscuration. The 6-12 mu m spectra are dominated by emission features of polycycl…
Stellar atmospheric parameters for the giant stars MU Pegasi and lambda Pegasi
Smith, G.
Profiles of the strong lines Ca II 8542 Angstroms, and Mg I 8806 Angstroms, together with regions containing Ca I, Fe I and Fe II lines in the spectra of the G8 giant stars mu Peg and lambda Peg have been recorded at high resolution and with signal/noise >= 100. The wings of the strong lines and the full profiles of intermediate strength lines …
On the systematic accuracy of the equatorial UBV standards
Evans, D. W.; Oja, T.
Using photometric data from the TYCHO experiment of the HIPPARCOS mission the discrepancies in B-V between the different series of measurement of the equatorial UBV standards have been studied. Corrections to the data by Landolt (1983) and Menzies et al. (1991) have been derived. based on observations made with the ESA Hipparcos satellite.
On the diamagnetic effect associated with the ion pile-up region in the coma of comet Halley
Neubauer, F. M.; Israelevich, P. L.; Ershkovich, A. I.
The ion pile-up region in the comet Halley ionosphere observed on the inbound leg of the Giotto trajectory is accompanied by a decrease of the magnetic field strength. This magnetic field dip is explained by means of a diamagnetic effect of the plasma density increase in the pile-up region. Maximum of the plasma pressure seems to coincide with the…
Extreme-ultraviolet diagnostics of pick-up ions in regions close to the solar corona. I. Feasibility of new observations
Fichtner, Horst; Fahr, Hans-Joerg; Scherer, Horst
Recent investigations of pick-up ion data obtained with the AMPTE and the Ulysses spacecraft resulted in the discovery that, in contrast to previous expectation, pick-up ion velocity distribution can be anisotropic. Such anisotropy results from a smaller efficiency of pitch-angle scattering than usually assumed and translates into a larger scatter…
HD 6226: a new bright B variable with occasional brightenings. Is it an unrecognized Be star?
Harmanec, P.; Bozic, H.
An analysis of differential UBV measurements of HD 6226 secured between 1982 and 1995 at Hvar, and combined with the Hipparcos satellite H_p photometry, led to the finding that this infrequently observed star is a new variable, characterized by occasional brightenings accompanied by the reddening of the B-V, and blueing of the U-B index. We note t…
ISO far-IR spectroscopy of the black hole candidate GRS 1915 + 105
Winkler, Christoph; Trams, Norman
referee We have observed the black hole candidate and Galactic superluminal source GRS 1915+105 with ISO LWS and SWS in March 1996 and March 1997 when the source was at fairly low X-ray and radio flux levels. If the source is associated with a dense molecular cloud, then corresponding far-IR continuum and line fluxes should be easily detectable an…
A first HIPPARCOS contribution to the light elements problem
Spite, M.; Crifo, F.; Spite, F.
{The interpretation of the observations of the light elements requires the knowledge of the evolutionary status of the observed stars. The HIPPARCOS accurate parallaxes solve several cases of ambiguous status. For example, it is shown that, since HD 84937 is a subgiant, its (6Li) abundance is compatible with the predictions of the standard models …
Minor planets ephemerides improvement. From joint analysis of HIPPARCOS and ground-based observations
Hestroffer, D.; Viateau, B.; Rapaport, M.
Two methods are considered for the improvement of the ephemerides of the asteroids observed by the Hipparcos satellite. They utilize different combinations of ground-based and space-based data. In particular, we develop a method based on an analysis of the variance matrix in the least-squares solution of Hipparcos observations taken alone. Applica…