Search Publications
An analysis of HST UV spectra of Cyg OB2 stars
Kudritzki, R. P.; Herrero, A.; Puls, J. +2 more
As a first step of a vigorous program to investigate the Wind Momentum - Luminosity Relationship (WLR) of Galactic O-stars by analyzing stars belonging to the same cluster we present UV HST observations of six supergiants and one giant in the
Radial evolution of outward and inward Alfvénic fluctuations in the solar wind: A comparison between equatorial and polar observations by Ulysses
Bavassano, B.; Pietropaolo, E.; Bruno, R.
Ulysses measurements done during the ecliptic phase of the mission are used to investigate the radial evolution of outward and inward Alfvénic fluctuations at hourly scale in near-equatorial solar wind. This analysis has been stimulated by a recent study on Alfvénic turbulence in polar wind, showing that at hourly scale different radial regimes de…
Hubble Space Telescope and Ground-based Spectroscopy of K648 in M15
Ford, Holland; Bianchi, Luciana; Bohlin, Ralph +2 more
We derive some element abundances for the central star of the planetary nebula K648 from analysis of Hubble Space Telescope Faint Object Spectrograph spectra (1200-3300 Å). Carbon is found to be approximately 4 times overabundant with respect to solar values, while oxygen is underabundant and silicon about solar, and He/H=0.6. The stellar continuu…
Simultaneous Chandra and Hubble Space Telescope Observations of SMC X-1
McCray, R.; Raymond, J. C.; Kallman, T. +3 more
We present first results from simultaneous ultraviolet (Hubble Space Telescope/STIS) and X-ray (Chandra/ACIS) observations of the SMC X-1/SK 160 eclipsing binary system. Observations covering four orbital phases during each of the X-ray high and X-ray low states were taken in 2000 October-November and 2001 April. The ultraviolet P Cygni lines show…
Observations of Lyα Absorption in a Triple Quasar System
Impey, C. D.; Foltz, C. B.; Young, P. A.
We have obtained follow-up observations of the quasar pair LBQS 0107-025A and B and new observations of the nearby quasar LBQS 0107-0232 with the Hubble Space Telescope Faint Object Spectrograph. Extended wavelength coverage of LBQS 0107-025A and B using the G270H grating was also obtained. This triple system is unique in providing sensitivity to …
a First and 11 Recalculated Orbits of Double Stars
Olevic, D.; Jovanovic, P.
We present the first orbit for the pair CHARA 130 as well as recalculated orbits for the following double stars: ADS 161, ADS 207, ADS 293, ADS 1393 ADS 2531, ADS 5707, ADS 6126, ADS 6532, ADS 6623, ADS 11247 and ADS 16914. Also, the comparison of obtained dynamical with the Hipparcos parallaxes is made. U radu su prvi put izracunati putanjski ele…
Multi-wavelength bispectrum speckle interferometry of R Leo and comparison with Mira star models
Weigelt, G.; Hofmann, K. -H.; Balega, Y. +1 more
We present diffraction-limited (30 mas resolution) bispectrum speckle interferometry of the Mira star R Leo with the 6 m SAO telescope. The speckle interferograms were recorded through narrow-band interference filters with centre wavelength/bandwidth of 673 nm/8 nm (strong TiO absorption band), 656 nm/10 nm, 699 nm/6 nm and 781 nm/14 nm (moderate …
Ionizing Photons and Extreme-Ultraviolet Excesses in Clusters of Galaxies
Bland-Hawthorn, J.; Maloney, Philip R.
Observations with the Extreme Ultraviolet Explorer satellite are purported to show extreme-ultraviolet (EUV) and soft X-ray excesses in several clusters of galaxies. If interpreted as thermal emission, this would imply the presence of warm (T~106 K) gas in these clusters with a mass comparable to that of gas at coronal temperatures. If …
Hubble Space Telescope-NICMOS Observations of M31'S Metal-Rich Globular Clusters and Their Surrounding Fields. II. Results
Rich, R. Michael; Jablonka, Pascale; Frogel, Jay A. +6 more
We have obtained HST-NICMOS observations of five of M31's most metal-rich globular clusters: G1, G170, G174, G177, and G280. For the two clusters farthest from the nucleus, G1 and G280, we statistically subtract the field population and estimate metallicities using K-(J-K) color-magnitude diagrams (CMDs). Based on the slopes of their infrared gian…
Dynamical variations of the differential rotation in the solar convection zone
Covas, E.; Moss, D.; Tavakol, R.
Recent analyses of helioseismological observations seem to suggest the presence of two new phenomena connected with the dynamics of the solar convective zone. Firstly, there are present torsional oscillations with periods of about 11 years, which penetrate significantly into the solar convection zone and secondly, oscillatory regimes exist near th…