Search Publications
The proper motions of fundamental stars. I. 1535 stars from the Basic FK5
Gontcharov, G. A.; Andronova, A. A.; Titov, O. A. +1 more
A direct combination of the positions given in the HIPPARCOS catalogue with astrometric ground-based catalogues having epochs later than 1939 allows us to obtain new proper motions for the 1535 stars of the Basic FK5. The results are presented as the catalogue Proper Motions of Fundamental Stars (PMFS), Part I. The median precision of the proper m…
Nature of the boundary between open and closed magnetic field line regions at the Sun revealed by composition data and numerical models
Riley, Pete; Gloeckler, George; Posner, Arik +5 more
Recently, Fisk et al. [1999] have presented a theory that describes a number of features of the large-scale coronal and heliospheric magnetic field. This theory predicts large-scale transport of magnetic flux across the boundaries of the polar coronal holes, which leads to reconnection processes of open field lines with preliminary closed magnetic…
Latitudinal velocity structures up to the solar poles estimated from interplanetary scintillation tomography analysis
Tokumaru, M.; Kojima, M.; Fujiki, K. +3 more
The Ulysses spacecraft observed high-speed wind at high latitudes up to 80° and found that the high-speed solar wind increased in velocity gradually with latitude and that the velocity had asymmetry between Northern and Southern Hemispheres. We have investigated the velocity increase up to the polar regions for the Carrington rotations of 1908-191…
UBV Photometry of the Massive Eclipsing Binary TT Aur
Demircan, O.; Saygaç, A. T.; Özdemir, S. +5 more
UBV observations of the massive binary system TT Aur were carried out mainly at the Turkish National Observatory (TUG). These observations, together with IUE spectra and times of eclipse minima collected from the literature, were used to study the system parameters. Simultaneous solution of the light curves by the Wilson-Devinney code allows a sem…
Middle Ultraviolet Spectroscopy of Pluto and Charon
Krasnopolsky, Vladimir A.
The first Pluto's spectrum in the range 2000 to 2500 Å has been extracted from the Hubble Space Telescope (HST) archive observations acquired during 24 orbits. Although the spectral intensity is very weak and smaller than that for Titan by a factor of 100, the spectrum has a signal-to-noise ratio of 10-15 at the resolution of 10 Å. The mean geomet…
The electron temperature of the inner halo of the Planetary Nebula NGC 6543
Hyung, S.; Kim, H.; Mellema, G. +1 more
We investigate the electron temperature of the inner halo and nebular core regions of
Optical variability of the B-type star HD 105382: Pulsation or rotation?
Aerts, C.; Briquet, M.; De Cat, P.
We present ground-based multi-colour Geneva photometry and high-resolution high S/N spectra of the variable B-type star HD 105382. We provide evidence that this star is not a Be star, as indicated in the literature. The monoperiodic variability found in the Hipparcos data is confirmed in our ground-based follow-up observations. All existing data g…
Stellar Variability in the Metal-rich, Obscured Globular Cluster Terzan 5
Edmonds, Peter D.; Grindlay, Jonathan E.; Cohn, Haldan +1 more
We present the results of a search for variability in and near the core of the metal-rich, obscured globular cluster Terzan 5, using the near-infrared camera and multiobject spectrometer (NICMOS) on board the Hubble Space Telescope. This extreme cluster has approximately solar metallicity and a central density that places it in the upper few perce…
WFPC2 Imaging of Quasar Environments: A Comparison of Large Bright Quasar Survey and Hubble Space Telescope Archive Quasars
Hooper, Eric J.; Impey, Chris D.; Finn, Rose A.
We present Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC2) data on the large-scale environments of 16 0.39<z<0.51 quasars from the Large Bright Quasar Survey (LBQS). The LBQS quasars are representative of the radio-quiet population, and this is one of the first looks at their large-scale environments. We compare the LBQS e…
The electron pressure in the outer atmosphere of ɛ Eri (K2 V)
McMurry, A. D.; Jordan, C.; Sim, S. A. +1 more
Observations of ɛ Eri (K2 V) have been made with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. The spectra obtained show a number of emission lines which can be used to determine, or place limits on, the electron density and pressure. Values of the electron pressure are required in order to make quantitative models of the…