Search Publications
SS 433 in the ultraviolet.
Dolan, J. F.; Boyd, P. T.; Fabrika, S. +8 more
The High Speed Photometer (HSP) on the Hubble Space Telescope observed SS 433 at 15 different epochs between 1993 May and November. Polarimetric observations were obtained in a 340Å FWHM bandpass centered at 2770Å; photometric observations were made in a bandpass extending between 1400 and 3000Å. The polarization in the UV is both large (
=13…Imaging the nuclear environment of NGC 1365 with the Hubble Space Telescope
Boksenberg, Alec; Lindblad, Per Olof; Kristen, Helmuth +1 more
The region surrounding the active nucleus of the barred spiral galaxy NGC 1365 is observed in the [Oiii] lambda 5007 line and neighbouring continuum using the Faint Object Camera (FOC) aboard the Hubble Space Telescope (HST). In the continuum light numerous bright ``super star clusters'' (SSCs) are seen in the nuclear region. They tend to fall on …
A 200km/s molecular wind in the peculiar carbon star V Hya.
Jorissen, A.; Knapp, G. R.; Young, K.
A molecular wind with an outflow speed in excess of 200km/s has been found in the AGB carbon star V Hya. Observations of several molecular lines show that the circumstellar envelope is expanding at 15km/s and is flattened and inclined to the line of sight. The fast wind appears to be expanding from the poles of the envelope, with the expansion spe…
Identification of moving groups from a sample of B, A and F type stars.
Figueras, F.; Torra, J.; Chen, B. +1 more
An algorithm to find moving groups has been developed and applied to a sample of 1924 B, A, and F main sequence stars, basically extracted from the Hipparcos Input Catalogue. This algorithm uses a non-parametric kernel estimator to describe the stellar distribution in a 4-dimensional space of velocities and age, although it can be used to detect t…
A theoretical approach to globular cluster low main sequence stars.
Cassisi, S.; Castellani, V.; degl'Innocenti, S. +3 more
This paper present new evolutionary computations extending toward the lower main sequence previous computations given for globular cluster stars. We discuss the physical inputs with particular regard to the limit of the adopted usual treatment of the stellar atmosphere, which allows a tight correlation with actual stellar structures only for selec…
The gravitational lensing nature of the Cloverleaf unveiled in CO (7-6) line emission.
Antonucci, R.; Tacconi, L.; Alloin, D. +2 more
We report 0.5" resolution imaging of the Cloverleaf quasar in the CO(7-6) line and 1.3mm continuum,, as well as 1" resolution imaging in the CO(3-2) line, performed with the IRAM interferometer. The CO(7-6) image is clearly resolved into 4 spots, demonstrating that the CO emission is also gravitationally lensed. We do not find any convincing evide…
Variations of the stellar wind in early-B hypergiants.
Stahl, O.; Wolf, B.; Lamers, H. J. G. L. M. +9 more
With our fiber-linked echelle spectrograph we monitored three early-B hypergiants with high dispersion and good coverage in time. The program stars ζ^1^ Sco (HD 152236), HD 169454, and HD 190603 were observed over periods of several months in several seasons. In the years 1990 to 1994, we covered the wavelength range from 4000Å to 6740Å and in 199…
Mid-IR colors and star formation in Virgo and Coma galaxies.
Boulanger, F.; Sauvage, M.; Contursi, A. +9 more
We present observations of the global emission of a sample of spiral and irregular galaxies in the Virgo cluster and the Coma supercluster. These observations have been made with the camera ISOCAM on board the Infrared Space Observatory, through two broad filters centered respectively at 6.75 and 15.0µm. The corresponding fluxes are correcte…
Barium stars, galactic populations and evolution.
Luri, X.; Figueras, F.; Torra, J. +4 more
In this paper HIPPARCOS astrometric and kinematical data together with radial velocities from other sources are used to calibrate both luminosity and kinematics parameters of Ba stars and to classify them. We confirm the results of our previous paper (where we used data from the HIPPARCOS Input Catalogue), and show that Ba stars are an inhomogeneo…
Fractionated stellar wind - the example of σ Orionis E.
Groote, D.; Hunger, K.
In main-sequence stars, at effective temperatures below =~20000K, radiation ceases to be able to drive a stellar wind. In a rather narrow transition regime, elemental segregation seems possible due to the decoupling of He and, under special circumstances, also of H from the absorbing metal ions in the wind. This effect may even be more pronounced,…