Search Publications
A study of bright southern slowly pulsating B stars. II. The intrinsic frequencies
Aerts, C.; De Cat, P.
We present the results of detailed frequency analyses of a sample of thirteen confirmed slowly pulsating B stars. Our analysis is based on a combination of elaborate photometric and spectroscopic data-sets. The original sample consists of a mixture of five confirmed slowly pulsating B stars and twelve candidate slowly pulsating B stars discovered …
Rotational velocities of A-type stars. I. Measurement of v sin i in the southern hemisphere
Royer, F.; Gerbaldi, M.; Faraggiana, R. +1 more
Within the scope of a Key Programme determining fundamental parameters of stars observed by HIPPARCOS, spectra of 525 B8 to F2-type stars brighter than V=8 have been collected at ESO. Fourier transforms of several line profiles in the range 4200-4500 Å are used to derive v sin i from the frequency of the first zero. Statistical analysis of the sam…
On the association between type II radio bursts and CMEs
Aurass, H.; Claßen, H. T.
Ground-based observations of metric (coronal) type II radio bursts are compared with observations of coronal mass ejections (CMEs) obtained by the LASCO coronagraph aboard SOHO and with decametric (interplanetary) type II bursts recorded by the WAVES instrument aboard Wind. The basic data sample comprises 63 metric type II radio bursts observed du…
A multi-epoch spectrophotometric atlas of symbiotic stars
Munari, U.; Zwitter, T.
A multi-epoch, absolute-fluxed spectral atlas extending from about 3200 to 9000 Å is presented for 130 symbiotic stars, including members of the LMC, SMC and Draco dwarf galaxies. The fluxes are accurate to better than 5% as shown by comparison with Tycho and ground-based photometric data. The spectra of 40 reference objects (MKK cool giant standa…
Multiplicity among chemically peculiar stars. II. Cool magnetic Ap stars
Babel, J.; Carrier, F.; Udry, S. +1 more
We present new orbits for sixteen Ap spectroscopic binaries, four of which might in fact be Am stars, and give their orbital elements. Four of them are SB2 systems: HD 5550, HD 22128, HD 56495 and HD 98088. The twelve other stars are: HD 9996, HD 12288, HD 40711, HD 54908, HD 65339, HD 73709, HD 105680, HD 138426, HD 184471, HD 188854, HD 200405 a…
On the intensity contrast of solar photospheric faculae and network elements
Solanki, S. K.; Sanahuja, B.; Ortiz, A. +2 more
Sunspots, faculae and the magnetic network contribute to solar irradiance variations. The contribution due to faculae and the network is of basic importance, but suffers from considerable uncertainty. We determine the contrasts of active region faculae and the network, both as a function of heliocentric angle and magnetogram signal. To achieve thi…
3D Coronal magnetic field from vector magnetograms: non-constant-alpha force-free configuration of the active region NOAA 8151
Amari, T.; Régnier, S.; Kersalé, E.
The Active Region 8151 (AR 8151) observed in February 1998 is the site of an eruptive event associated with a filament and a S-shaped structure, and producing a slow Coronal Mass Ejection (CME). In order to determine how the CME occurs, we compute the 3D coronal magnetic field and we derive some relevant parameters such as the free magnetic energy…
Dust depletion and abundance pattern in damped Lyalpha systems: A sample of Mn and Ti abundances at z < 2.2
Petitjean, P.; Bergeron, J.; Ledoux, C.
We analyse a sample of 24 damped Lyman-alpha (DLA)/moderate DLA systems at intermediate redshifts, 0.3<zabs<2.2, all with measurement of the weak Mn II absorption lines, to investigate which elemental ratios could possibly be used as tracers of either dust depletion or nucleosynthesis effects. We applied a component-by-component a…
Ice features in the mid-IR spectra of galactic nuclei
Lutz, D.; Tielens, A. G. G. M.; Moorwood, A. F. M. +3 more
Mid infrared spectra provide a powerful probe of the conditions in dusty galactic nuclei. They variously contain emission features associated with star forming regions and absorptions by circumnuclear silicate dust plus ices in cold molecular cloud material. Here we report the detection of 6-8 mu m water ice absorption in 18 galaxies observed by I…
On Be star candidates and possible blue pre-main sequence objects in the Small Magellanic Cloud
Mennickent, R. E.; Gieren, W.; Pietrzyński, G. +1 more
Recently the OGLE experiment has provided accurate light curves and colours for about 2 millions stars in the Small Magellanic Cloud. We have examined this database for its content of Be stars, applying some selection criteria, and we have found a sample of ~ 1000 candidates. Some of these stars show beautiful light curves with amazing variations …