Astronomy and Astrophysics Letters dedicated to ISO

ISOCAM imaging of AG Car and HR Car

N.R.Trams - L.B.F.M. Waters - R.H.M. Voors


We present infrared images obtained with the ISOCAM instrument on board the Infrared Space Observatory of two Luminous Blue Variables (AG Car and HR Car). The images were obtained at eight wavelengths between 8.5 and 16  microns using the Circular Variable Filters (CVFs), with a pixel size of 6 by 6 arcsec and a total field of view of 192 by 192 arcsec. The nebula around AG Car is clearly resolved. The nebula is particularly strong in the [Ne II] emission line and at the longer wavelengths in the continuum. Using these images independent spectral energy distributions are obtained of the star and the nebula. The spectral energy distribution indicates that most of the infrared radiation in AG Car originates in the extended nebula, and may be due to thermal radiation of dust in the nebula. In fact most of the IR radiation of this object longward of 10  microns originates in the nebula. The star HR Car is not clearly resolved, although the spectra calculated by adding the pixels show some marked differences between the spectrum of the central pixel and the area around the central pixel, indicating the presence of extended emission also in this object.

Stars: imaging - Stars: circumstellar matter - Stars: early type; Infrared: stars

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