> this is a continuation and iso follow up of proposal rsiebenm.rsiehebe > we request more observing time. > 11061s grade 6 and 7199 grade 8 time for this proposal is to be > transferred from rsiebenm.rsiehebe. we propose to study extended emission of intermediate mass pre-main sequence stars. we have selected a sample of nearby herbig ae/be stars. we will investigate the contribution of individual dust populations (large grains, small graphites, pah) to the overall energetics of the halo. for this end, the well known mid ir excess of the objects will be imaged at different cvf positions. the detailed picture of the circumstellar environment will be used to disentangle the luminosity of the disk and envelope. our radiative transfer models will be constrained by far ir maps. out of these maps we will derive physical parameters such as far ir sizes, colour temperatures, total dust mass, density distributions and opacities. one of our target (hd97300) has been observed and show the predicted extended emission. the cam images show an unpredicted spectacular ring emission surrounding hd97300 (see figure). the ring can be explained by means of radiative transfer models including small grain components. however, a direct proof of the presence of small grains will only come from the here requested additional cvf scan on the ring. in order to probe unambiguously the predicted extended emission we request additional narrow band images in pah filter lw4 and reference filter lw5. we ask for observing time for two additional targets from our spring list and a compensation for virgul20% higher overheads in our p32 observations as compared to phase 1 submission of the first iso call.
Instrument
CAM01 , CAM04 , PHT22
Temporal Coverage
1997-04-24T19:30:14Z/1997-11-04T08:26:48Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the world's first true orbiting infrared observatory. Equipped with four highly-sophisticated and versatile scientific instruments, it was launched by Ariane in November 1995 and provided astronomers world-wide with a facility of unprecedented sensitivity and capabilities for a detailed exploration of the Universe at infrared wavelengths.
