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Galileo Avionica's Technologies and Instruments for Planetary Exploration
Re, E.; Battistelli, E.; Falciani, P. +3 more
Several missions for planetary exploration, including comets and asteroids, are ongoing or planned by the European Space Agencies: Rosetta, Venus Express, Bepi Colombo, Dawn, Aurora and all Mars Programme (in its past and next missions) are good examples. The satisfaction of the scientific request for the mentioned programmes calls for the develop…
A search for two-component energetic proton events observed on board SOHO
Kocharov, Leon; Torsti, Jarmo; Al-Sawad, Amjad +1 more
We examined solar energetic particle (SEP) events from May 1996 through April 2000 that showed evidence for two peaks of intensity, separated by 3-24 hours, in the energy range ∼1-20 MeV, observed with the Energetic and Relativistic Nuclei and Electron instrument (ERNE) onboard Solar and Heliospheric Observatory (SOHO). Of 88 clear SEP events obse…
Empirical Modeling of TSI: A Critical View
de Toma, Giuliana; White, Oran R.
Solar empirical models based on regression of two variability indices for radiation from the photosphere and chromosphere fit total solar irradiance (TSI) observations with accuracy comparable to the precision reported for the observations themselves. However, the physical meaning of the fitting coefficients and their stability during different ph…
Two years of INTEGRAL observation of the BHC IGR J17464-3213
Capitanio, F.; Ubertini, P.; Bazzano, A. +4 more
On March 2003, IBIS, the γ-ray imager on board the INTEGRAL satellite, detected an outburst from a new source, IGR J17464-3213, that turned out to be an HEAO-1 transient, namely H1743-322. The spectral and temporal evolutions of the source were observed by INTEGRAL in different periods. Also RXTE observed the source for the first time on 2003 Marc…
Pulsating B Stars Discovered by HIPPARCOS
Eyer, L.; Aerts, C.; De Cat, P. +4 more
We present a classification of 267 new variable B-type stars discovered by Hipparcos, which results in, among others, a huge number of new Slowly Pulsating B stars and several supergiants with ? Cyg-type variations. Our results clearly point out the bias towards short-period variables of earlier, ground-based surveys of variable stars.
The po…Discovery of a cluster of galaxies behind the Milky Way: X-ray and optical observations
Motch, C.; Mendes de Oliveira, C.; Janot-Pacheco, E. +2 more
We report the discovery of
Analysis of chromospheric activity in late type stars from UV observations
Buccino, A. P.; Mauas, P. J. D.
The purpose of this work is to study the chromospheric activity of the latest main sequence stars, which are generally observed in low dispersion. In this work, we present a calibration between Mount Wilson index and the Mg II line-core flux, measured on simultaneous low resolution IUE spectra. FULL TEXT IN SPANISH
The broad-band spectrum of Cyg X-2 with INTEGRAL
Stella, L.; van der Klis, M.; Lewin, W. H. G. +7 more
We study the broad band (3-100 keV) spectrum of Cygnus X-2 with INTEGRAL. We find that the spectrum is well fitted by a Comptonized component with a seed-photons temperature of ∼ 1 keV, an electron temperature of ∼ 3 keV and an optical depth τ ∼ 8. Assuming spherical geometry, the radius of the seed-photons emitting region is ∼ 17 km. The source s…
The Type Ia Supernova rate in the local Universe
Strigari, Louis E.
Current measurements of the Type Ia Supernova (SNIa) rate, as determined by standard astronomical methods, are in reasonable agreement with measurements of the cosmic star formation rate combined with simple models for SNIa progenitors. However, systematic uncertainties still undermine a precise determination of the SNIa rate. Recent models of the…
The Precataclysmic Binary HS 1136+6646 May Have a Companion
Holberg, J. B.; Sing, D. K.; Liebert, James +1 more
Because of the similarity of the primary star of HS 1136+6646 to the planetary nebula central star BE Ursae Majoris, we performed wide-field imaging of the former with an Hα filter. No nebulosity was detected. On the other hand, the point-spread function of the star appears extended. A partially resolved red component is detected in an image from …