| Description |
scientific abstract: emission features are often observed in the near and mid-infrared spectra of planetary(pne) and protoplanetary nebulae(ppne). these include nebular emission from recombination and collisionally excited lines, emission lines due to ne, ar and s, and unidentified infrared (uir) emission features attributed to polycyclic aromatic hydrocarbons (pahs). the present proposal, that is the first part of a general proposal of pne and ppne, consists in studying the differences in spatial distribution of these emission features, for a selected number of pne and ppne. observation summary: the differences in spatial distribution of atomic lines, thermal dust, and small grains (pahs), will be obtained with cam observations in cvf mode (cam04). for the brightest pne and ppne (crl2688,ngc7027,hd44179,bd303639), spectral images will be taken with a p.f.o.v of 1.5 arcsec at 85 cvf positions between 5 and 16.5 micron and 13 cvf positions between 3.6 and 4.3 micron. to avoid saturation, an integration time per point of 0.28 sec will be used for the lw spectra, and 6 sec for the sw. the sources ic418,ngc6302,ngc6543, and vy2-2 will be observed with the same p.f.o.v., but with an integration time per point of 2 sec in lw, and only 6 cvf positions between 3.9 and 4.2 micron. finally, for the pne ngc2346 and ngc6720,proposed to be observed in priority 3, only 15 spectral positions in cvf lw centered at 6.2 micron (5.9-6.3;4 points), 7.7 micron (7.4-8.1;7 points), and 11.3(10.9-11.6;4 points) are required with a p.f.o.v of 3 arcsec and tin= 10 sec/point. in addition, spectral images at 3 cvf positions around 4.04 micron (br-alfa line) will be obtained for these pne using tin= 20 sec /point. the expected s/n is greater than 40 for the lw spectra, and 10-20 for the sw cvf observations. |
