FIR IMAGING DUST HALOS OF PROTOPLANETARY AND PLANETARY NEBULAE A STUDY OF MASS LOSS HISTORY

we propose to obtain linear scans of the thermal emission from dust in the envelopes of 7 to 8 protoplanetary nebulae (ppne) and planetary nebulae (pne) at 95um and 170um using the isophot fir arrays, c100 and c200 respectively. the two goals of these observations is (1) to determine the history of mass loss as imprinted on the circumstellar dust envelopes in these ppne and pne, and (2) to measure the total mass of the circumstellar dust from which we can infer a lower limit to the initial mass of the progenitor main sequence star. in particular, the radial profiles of dust density derived from these observations will test current theories of episodic mass loss and accelerated mass loss. understanding this mass loss process is a key problem within astrophysics because most of interstellar dust and gas originates from these stellar sources. iso provides the necessary sensitivity and longer wavelength coverage to detect the virgul35k thermal dust halos surrounding ppne and pne. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]