scientific abstract the objectives of this proposal are the following: 1. investigate the abundances of iron, magnesium, silicon in planetary nebulae. for iron, very little is known. for the other elements iue spectra are available, but only for some nearby nebulae. these elements have useful lines in the sws spectral range. we propose to measure these abundances in a variety of nebulae. 2. carbon abundances, as deduced from iue observations, are not well understood. to help resolve this question, we propose to try to observe the cii line at 157 microns in a number of galactic-bulge nebulae, for which we have reliable distance estimates. the nii line at 120 microns, which will also be measured, will help in the interpretation, allowing to distinguish between the central star and circumstellar material. 3. h2, oi and cii lines will be measured in a number of nebulae to try to assess the amount of neutral material surrounding some nebulae. the oi and cii lines are in the lws range. 4. for two bright high-excitation nebulae full-resolution full sws scans will be made and a number of lines will be studied in more detail. the results will serve as bench marks for other studies in the sws central program. 5. one extended nebula will be investigated by observing a number of lines in a raster, to explore the excitation variations through the nebula. observation summary observation modes are detailed in the scientific justification. summary of proposed observations: obs. modes spring autumn 1 ic418 s11 s2h p 34 min 2 ngc 2346 s11 s2 p 30 min 3 ngc 2440 s14 p 112 min s2f 35 min 4 ngc 3132 s11 s2 p 30 min 5 ngc 3242 s11 s2 p 30 min 6 ngc 3918 s11 s2 p ... 30 min 30 min 7 ngc 5315 s11 s2 p 30 min 8 he2-113 s11 s2h p 34 min 9 he 2-131 s11 s2 p 30 min 10 ngc 6153 s11 s2 p 30 min 11 ngc 6302 s14 p 112 min s2f 35 min 12 ngc 6543 s11 s2 p 30 min 30 min 13 ngc 6537 s11 s2 p 30 min 14 ngc 6572 s11 s2 p 30 min 15 vy 2-2 s11 s2h p 34 min 16 bd+30 3639 s11 s2h p 34 min 17 ic4997 s11 s2h p 34 min 18 ngc 7027 s14 p 112 min 112 min s2f 35 min 35 min 19 iras21282+5050 s12 l 49 min 49 min 20 pk350+4.1 s12 l 49 min 21 pk355+3.2 s12 l 49 min 22 pk359-1.2 s12 l 49 min 23 pk359-2.3 s12 l 49 min 24 cn 1-5 s12 l 49 min 25 ngc 246 s2r 12 min 12 min 26-36 ngc 246 (continued, raster) s2r 99 min 99 min total 638 min 1045 min 10.6 hrs 17.4 hrs
Instrument
CAM01 , LWS01 , PHT40 , SWS01 , SWS02 , SWS06
Temporal Coverage
1996-02-04T10:15:10Z/1998-02-28T17:22:25Z
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.
