Search Publications
ISOCAM observations of NGC 6946: Mid-IR structure.
Helou, G.; Lord, S. D.; Malhotra, S. +12 more
The nearby spiral galaxy NGC 6946 was observed with ISO-CAM in the mid-infrared, achieving 7" resolution and sub-MJy/sr sensitivity. Images taken with CAM filters LW2 (7µm) and LW3 (15µm) are analysed to determine the morphology of this galaxy and understand better the emission mechanisms. The mid-infrared emission follows an exponenti…
The infrared and radio continuum of early-type stars.
Blomme, R.; Runacres, M. C.
The infrared and radio continuum fluxes of 18 well-observed early-type stars are studied by comparing observations with theoretical models. The observations are taken from the literature. All available observations are included. The theoretical NLTE models for photosphere and stellar wind include free-free and free-bound emission as well as electr…
ISOPHOT Maps of NGC 6946 in the range λ 60-200µm.
Helou, G.; Lemke, D.; Gabriel, C. +7 more
We present maps of NGC 6946 at λ 61 and 205µm as well as scans through the galaxy at these and at 8 intermediate wavelengths. The bulk of the FIR luminosity arises from a diffuse disk component which extends beyond the 25mag/arcsec^2^ B isophote to at least the radius corresponding to the sensitivity limit. A FIR emission counterpart to the …
Accretion torques in the transient X-ray pulsar EXO2030+375.
Parmar, A. N.; Verbunt, F.; Wilson, R. B. +4 more
In 1985 May - October, EXOSAT observed two outbursts from the previously unknown accreting X-ray pulsar EXO2030+375. Using the orbital solution derived by the BATSE experiment on CGRO, the behavior of the pulse period variations can now be studied with much less ambiguity than was possible based on the EXOSAT observations alone. There is little ev…
PU Vulpeculae: an eclipsing symbiotic nova.
Vogel, M.; Nussbaumer, H.
A series of IUE observation from 1992 to 1995 has definitely established PU Vul as an eclipsing binary. The outburst of this symbiotic nova began in 1977. An extended fading in 1980 gave rise to various interpretations, the eclipse scenario being one of them, dust formation being another. From AFOEV and AAVSO observations we find a period of 4900+…
On the width of the theoretical lower main sequence. Consequences for the determination of the {DELTA}Y/{DELTA}Z ratio in the solar neighbourhood.
Baglin, A.; Lebreton, Y.; Fernandes, J.
We discuss the relation between the main sequence thickness and chemical composition variations. With the help of theoretical zero-age main sequence models between 0.7 and 1.0Msun_, computed with an advanced physical description of the stellar interiors, in a range of metallicities typical from Population I stars (0.008<=Z<=0.034)…
The remarkable Herbig AE star V 351 Orionis=HD 38238.
The, P. S.; de Winter, D.; van den Ancker, M. E.
The photometric behaviour of the irregular variable Herbig Ae star V 351 Ori was investigated combining data from the literature with new photometric data in the Stroemgren system. It is shown that this enigmatic object changed its photometric behaviour from that of a Herbig Ae star with strong photometric variations, due to extinction by circumst…
The central star of the planetary nebula NGC 6302.
Pottasch, S. R.; Beintema, D.; Vandenbussche, B. +3 more
Selected results from the ISO spectrum of NGC 6302 are reported. The intensity of the high ionization [Mg VIII] line is given. The controversy concerning the mechanism of ionization of the high ionization stages, and especially the [NeV] lines is discussed. It is concluded that all lines can be reproduced in a photoionization model, if the tempera…
Very cold dust associated with molecular gas.
Prusti, T.; Burgdorf, M.; Laureijs, R. J. +4 more
We report the detection of very cold dust in a small and isolated dust cloud. Observations at 60, 90, 135, and 200µm show a constant surface brightness ratio I_135_/I_200_ and a flattening of I_90_/I_200_ towards the cloud centre. The dust temperature derived from the far-infrared colours can be confined to the range of 12-15K assuming a λ^-…
Time and space variations of the Galactic cosmic ray electron spectrum in the 3-D heliosphere explored by Ulysses.
Sierks, H.; Kunow, H.; Wibberenz, G. +7 more
The Ulysses spacecraft, launched in Oct. 90 after solar maximum of solar cycle 22, has explored the heliographic latitudes above 70degS in summer 94, and has then made a rapid latitude scan down to the heliographic equator reached in March 95, in a period close to solar minimum. We present hereafter the Galactic electron spectra, with energies abo…