Search Publications
Tomographic Separation of Composite Spectra. VI. The Physical Properties of the Massive Close Binary HD 152248
Gies, Douglas R.; Penny, Laura R.; Bagnuolo, William G., Jr.
We present the results of a Doppler tomographic reconstruction of the UV spectra of the double-lined O binary HD 152248 based on observations made with IUE. We used cross-correlation methods to obtain radial velocities, confirm the orbital elements, estimate the UV flux ratio, and determine projected rotational velocities. The individual component…
X-Ray Observations of the Seyfert Galaxy LB 1727 (1H 0419-577)
Nandra, K.; Turner, T. J.; Kraemer, S. B. +6 more
We discuss the properties of the Seyfert 1.5 galaxy LB 1727, also known as 1H 0419-577, from X-ray observations obtained by ASCA and ROSAT, along with optical observations from earlier epochs. The source flux was F2-10~=10-11 ergs cm-2 s-1 during the ASCA observations that were carried out during 1996 Ju…
Earth Rotation Parameters 1899.7 :1992.0 After Reanalysis Within The Hipparcos Frame
Vondrák, Jan.
Earth rotation parameters (ERP) in the interval 1899.7-1992.0 are obtained from re-analysis of the observed latitude/universal time variations by optical astrometry. Hipparcos Catalogue is used to define the celestial reference frame, within which the ERP are described, with special care devoted to 'problematic' double and/or multiple stars. The t…
The nature of the circumstellar CO_2 emission from M giants
Ryde, N.; Eriksson, K.; Gustafsson, B.
The 13-16mu m region observed by the Infrared Space Observatory (ISO) of several ABG stars are discussed. We present and analyse spectra of seven M giants which show carbon dioxide features. To explain the features of the bands, we suggest they originate from two different circumstellar layers, one being a warm and high density layer close to the …
Space-age distribution of young open clusters and observational selection
Dambis, A. K.
Based on published photoelectric and CCD photometry and using the empirical ZAMS of Kholopov (1980) and the evolutionary-deviation curves obtained from the grid of isochrones computed by Maeder and Meynet (1991), we determine the distances, color excesses, and ages for 203 Galactic open clusters with log t < 8.2. The validity of the derived dis…
No Increase of the Red Giant Branch Tip Luminosity toward the Center of M31
Meynet, G.; Jablonka, P.; Sarajedini, A. +3 more
We present observations with the Hubble Space Telescope Wide-Field Planetary Camera 2 of three fields centered on super-metal-rich globular clusters in the bulge of M31. Our (I, V-I) color-magnitude diagrams reach as faint as I~26.5 mag and clearly reveal the magnitude of the first-ascent red giant branch (RGB) tip. We find that the apparent I mag…
Dust in the wheel: The Cartwheel galaxy in the Mid-IR
Cesarsky, C.; Sauvage, M.; Appleton, P. N. +5 more
We present mid-infrared images at 6.7 µm and 15 µm of ``The Cartwheel'' (AM 0035-33), the prototypical collisional ring galaxy. The observations, taken with ISOCAM, reveal the distribution of hot dust in the galaxy and its two companions in the north-east. The intensity of the Mid-IR emission from the outer star forming ring of the Car…
Solar wind ionic charge states during the Ulysses pole-to-pole pass
Galvin, Antoinette B.; Gloeckler, George; Ko, Yuan-Kuen +1 more
We analyze and compare the ionic charge composition data for different types of the solar wind (slow wind from equatorial regions, fast wind from low-latitude coronal hole and fast wind from both south and north polar coronal hole) which the Solar Wind Ion Composition Spectrometer (SWICS) on Ulysses observed during the pole-to-pole pass of its pri…
NICMOS and VLBA observations of the gravitational lens system B1933+503
Jackson, N.; Browne, I. W. A.; Wilkinson, P. N. +1 more
NICMOS observations of the complex gravitational lens system B1933+503 reveal infrared counterparts to two of the inverted-spectrum radio images. The infrared images have arc-like structures. The corresponding radio images are also detected in a VLBA map made at 1.7 GHz with a resolution of 6 mas. We fail to detect two of the four inverted radio s…
Energetic (~10-65 MeV) protons observed by ERNE on August 13-14, 1996: Eruption on the solar back side as a possible source of the event
Laitinen, T.; Vainio, R.; Valtonen, E. +6 more
The onset of the >10-MeV proton event of August 13-14, 1996, revealed a velocity dispersion, which is a signature of its solar origin, but no associated soft X ray flare was observed. The LASCO CME observations, the presence of AR 7981 beyond the west limb, and type II and IV radio burst timing with respect to the proton event onset indicate th…