Search Publications
MgS in detached shells around carbon stars. Mining the mass-loss history
Hony, S.; Bouwman, J.
We investigate the dust composition of detached shells around carbon stars, with a focus to understand the origin of the cool magnesium-sulfide (MgS) material around warm carbon stars, which has been detected around several of these objects \citep{2002A&A...390..533H}. We build a radiative transfer model of a carbon star surrounded by an expan…
Me 1-1: A PN containing a cool star
Liu, X. -W.; Danziger, I. J.; Shen, Z. -X.
We report the detection of a cool stellar component at the center of the planetary nebula (PN) Me 1-1 and present optical spectra of the system. From measurements of nebular emission lines, we have derived electron temperature, density and chemical composition. Heavy elemental abundances deduced from collisionally excited lines (CELs) are compared…
308 Polyxo: ISO-SWS spectrum up to 26 micron
Barucci, M. A.; Dotto, E.; Müller, T. G. +2 more
Infrared spectroscopic observations of the asteroid 308 Polyxo have been carried out by the Infrared Space Observatory (ISO) with the Short Wavelength Spectrometer (SWS) in the spectral region between 7 and 26 µm. The Standard Thermal Model and the Thermophysical Model have been applied to the obtained data in order to model the thermal cont…
Evidence for magnetic reconnection in the high corona
Simnett, G. M.
The LASCO C2 coronagraph on the SOHO spacecraft shows many examples of oppositely-directed mass flows along the same (projected) radius vector. We have analysed 40 such events to understand their origin and possible physical cause. The events all had the speed of the outflowing feature higher than that of the inflowing feature. This is interpreted…
Intermediate-age globular clusters in early-type galaxies: Better age determinations by adding U-band observations to the V, I, K datasets
Kissler-Patig, M.; Hempel, M.
This paper represents an extension to a series of publications on combined optical and near-infrared photometry of globular cluster systems in early-type galaxies. Based on color-color diagrams the cumulative age distributions of their globular cluster systems have been derived and revealed intermediate age clusters in two galaxies, namely NGC 436…
XMM-Newton observation of the Seyfert 1 ESO 198-G24
Kaastra, J. S.; O'Brien, P. T.; Porquet, D. +3 more
We present the results from an XMM-Newton observation (January 24, 2001) of the bright Seyfert 1 galaxy
Cumulants and symmetries in a trivariate normal mixture. A qualitative study of the local velocity distribution
Cubarsi, R.; Alcobé, S.
An alternative parameterization of a trivariate normal mixture for the stellar velocity distribution provides a set of constraint equations between global cumulants that are used to estimate characteristic constants of the mixture and population parameters. Under particular distribution symmetries these relationships become simpler and easy to eva…
Discovery of a new INTEGRAL source: IGR J19140+0951
Rodriguez, J.; Henri, G.; Petrucci, P. O. +5 more
IGR J19140+0951 (formerly known as IGR J19140+098) was discovered with the INTEGRAL satellite in March 2003. We report the details of the discovery, using an improved position for the analysis. We have performed a simultaneous study of the 5-100 keV JEM-X and ISGRI spectra from which we can distinguish two different states. From the results of our…
Stellar activity and magnetism studied by optical interferometry
Jankov, S.; Kilbinger, M.; Lanz, T. +5 more
By means of numerical simulations, we investigate the ability of optical interferometry, via the fringe phase observable, to address stellar activity and magnetism. To derive abundance maps and stellar rotation axes, we use color differential interferometry which couples high angular resolution to high spectral resolution. To constrain magnetic fi…
Optical and infrared spectroscopic analysis of the post-AGB star candidate IRAS 19386+0155
Pereira, C. B.; Lorenz-Martins, S.; Machado, M.
This work reports high-resolution spectroscopic stellar parameters and abundance analysis of the post-AGB star IRAS 19386+0155. The analysis of the high resolution spectrum shows that it has an effective temperature of Teff=6800±100 K and a surface gravity of log g = 1.4±0.2. The abundance analysis reveals IRAS 19386+0155 to be a metal-…