Search Publications

Interstellar extinction: a parametrical study by using laboratory data.

Mennella, V.; Colangeli, L.; Rotundi, A. +2 more

The authors present a comparative study between laboratory data, astronomical observations and theoretical models in order to provide a contribution to the characterization of cosmic-dust properties. In particular, they propose a parametrization of the amorphous-carbon extinction curve. The laboratory extinction measurements, performed in the extr…

Stellar winds of massive stars in M31

Hutchings, John; Bianchi, Luciana

We have obtained the first UV high resolution spectra of hot luminous stars in M31 with the FOS onHubble Space Telescope. The spectra, combined with optical spectroscopic and photometric observations, enable us to study their stellar winds and photospheric parameters. We derive mass-loss rates and velocity laws from the wind line profiles, with th…

Ulysses-its status and prospects

Wenzel, K. -P.

The Ulysses spacecraft is in a high-inclination solar orbit to reach the south polar regions of the Sun in mid-1994 and the north polar regions about one year later. The spacecraft and its nine scientific instruments are in good health. An extended mission, i.e. a second orbit with polar passes about half an 11-year solar cycle later, is scientifi…

Theoretical Modes Fitting on Miras Light Curves

Barthes, D.; Mennessier, M. O.; Mattei, J. A. +1 more

Visual observations of long period variable stars over 20 years were provided by the American Association of Variable Stars Observers (AAVSO), and were analyzed as part of the preparation of the HIPPARCOS mission. A set of frequencies is extracted from the light curve by using Fourier transform, preliminary Van Cittert deconvolution and comparison…

Observing the Solar Wind Between 1 and 4 AU with the Radio Receiver on Ulysses

Pantellini, F.; Forsyth, R. J.; Stone, R. G. +8 more

Energetic particle results from ulysses (extended abstract)

Sierks, H.; Kunow, H.; Wibberenz, G. +6 more

Charged-particle induced background expected in X-ray detecting CCDs in highly eccentric earth orbits

Danner, R.

Charged particle fluxes on satellites in highly eccentric Earth orbits are studied, using data from ISEE1 and EXOSAT missions. The effects of minimum-ionizing particles, low-energy electrons and secondary radiation produced by these particles on CCDs used as X-ray detectors are identified. A technique to discriminate events caused by minimum-ioniz…

Radio waves in the heliosphere

Bougeret, J. -L.

Solar radio emissions at long wavelengths (wavelengths greater than 10 m or frequencies smaller than 30 MHz) are produced in the upper corona and in the interplanetary medium (the Heliosphere), sometimes at very large distances from the Sun, up to the orbit of Jupiter and beyond. Solar radio emissions are produced by the passage of energetic parti…

The new Be-type star HD 147196 in the rho Ophiuchi dark cloud region.

Perez, M. R.; The, P. S.; de Winter, D. +1 more

The newly discovered hot-emission line star, HD 147196 in the Rho Oph dark cloud region was observed spectroscopically and photometrically and high and low resolution IUE spectra were obtained. The finding of Irvine (1990) that this relatively bright star show its H-alpha-line in emission is confirmed. Previous H-alpha-surveys of the Rho Oph star-…

The Proton and Alpha Spectra in and out of the Ecliptic, and the Appearance of the Anomalous He Component - Ulysses Observations

Kunow, H.; Heber, B.; Ferrando, P. +6 more