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Geneva photometry of the open cluster NGC 2451 and its exceptional Be star HR 2968 satellite.}
Carrier, F.; Burki, G.; Richard, C.
During many years, several authors discussed whether
Full disk helioseismology: repetitive music and the question of gap filling
Hoeksema, J. T.; Grec, G.; Cacciani, A. +8 more
Helioseismology requires continuous measurements of very long duration, months to years. This paper addresses the specific and limited case of full disk measurements of p-mode oscillations, although it can be generalized, to some extent, to the case of imaged helioseismology. First, a method of mode by mode (or rather pair of modes by pair of mode…
The nature of the circumstellar CO_2 emission from M giants
Ryde, N.; Eriksson, K.; Gustafsson, B.
The 13-16mu m region observed by the Infrared Space Observatory (ISO) of several ABG stars are discussed. We present and analyse spectra of seven M giants which show carbon dioxide features. To explain the features of the bands, we suggest they originate from two different circumstellar layers, one being a warm and high density layer close to the …
Dust in the wheel: The Cartwheel galaxy in the Mid-IR
Cesarsky, C.; Sauvage, M.; Appleton, P. N. +5 more
We present mid-infrared images at 6.7 µm and 15 µm of ``The Cartwheel'' (AM 0035-33), the prototypical collisional ring galaxy. The observations, taken with ISOCAM, reveal the distribution of hot dust in the galaxy and its two companions in the north-east. The intensity of the Mid-IR emission from the outer star forming ring of the Car…
The integrated magnetic field of the Sun as seen by GOLF on board SOHO
García, R. A.; Turck-Chièze, S.; Ulrich, R. K. +7 more
An objective of the GOLF experiment (Global Oscillations at Low Frequencies) on-board the SOHO (Solar and Heliospheric Observatory) space mission was to measure the line-of-sight component of the disk-averaged magnetic field of the Sun. In this paper, a theoretical study of this observable is presented. The newly developed techniques are tested us…
Kinematics and age of stellar populations in the solar neighbourhood from Hipparcos data
Badiali, M.; Cardini, D.; Emanuele, A. +3 more
The large sample of main sequence stars with Hipparcos parallaxes and estimates of the radial velocity has been used to study the relations among kinematics, age and heavy element content for the solar neighbourhood. The samples with V > -30 km s-1, although including stars as old as 1010 yr, have a very young component (a…
Analysis of UV and optical spectra of the helium-rich white dwarfs HS 2253+8023 and GD 40
Reimers, D.; Heber, U.; Koester, D. +2 more
HS 2253+8023 is a helium-rich white dwarf with traces of metals and hydrogen, which was recently discovered in the Hamburg Quasar Survey. We have derived temperatures and element abundances from optical and UV spectra by comparison with synthetic line profiles. In addition UV (HST, IUE) and optical spectra of the well-known white dwarf GD 40 with …
Improved analysis of interplanetary HST-H_Ly\alpha spectra using time-dependent modelings
Fahr, Hans J.; Bzowski, Maciej; Scherer, Horst +1 more
During a period of 18 months 5 Hubble-Space-Telescope GHRS interplanetary H_{Lyalpha } glow spectra were obtained at different lines of sight from different positions of the earth on its orbit, but despite employment of a radiation transport model that takes into account the angle-dependent partial frequency redistribution, the self-absorption by …
Grain populations in the M 17 south-west star forming complex
Léger, A.; Rouan, D.; Giard, M. +3 more
The different spectral components of the 3-12 mu m dust emission are imaged in the M 17 south-west molecular cloud / Hriptsize{II} region interface. The various images result from a combination of space borne (ISO) and ground based (CFHT) observations. A spatial correlation analysis shows that there are two main components, which correspond to the…
An investigation of the B335 region through far infrared spectroscopy with ISO
Liseau, R.; White, G. J.; Benedettini, M. +11 more
We present far infrared spectra of the B335 dark cloud region, obtained with the Long Wavelength Spectrometer (LWS) on-board the ISO satellite. Deep spectra were obtained towards the far infrared outflow exciting source, located in the B335 core, and on the three associated Herbig Haro (HH) objects HH119 A, B and C. In addition, a region of about …