scientific abstract the circumstellar environment around evolved stars is mainly build up in several mass loss episodes during the evolution of the stars. the morphology and chemical composition of the circumstellar material of evolved stars will provide information on the evolutionary phase of the star during which the mass loss took place. we propose to study the circumstellar environment of three stars that are known to have extended emission. these stars are the luminous blue variables ag car and hr car and the be star hdvirgul87643. the proposal includes observations at several wavelengths using the camera (isocam) with the circular variable filters plus some sws line scans of molecular lines at some positions in the nebulae. the total on source observing time requested is 5290virgulseconds. observation summary the circumstellar environment of three evolved massive stars will be studied using cam and sws. for two objects (ag car and hr car) cam (cam01) images will be taken with a pixel field of view of 6 arcsec, using the cvf set at the wavelengths of a number of selected forbidden lines, and the adjacent continuum. the lines are ariii 8.991 micron, siii 12.01 micron, neii 12.814 micron and neiii 15.55 micron. for the third source (hd87643) cam (cam01) images will be taken with a pixel field of view of 6 arcsec using filters lw5 (6.75 micron), lw8 (11.3 micron) and lw9 (15 micron). furthermore for this source cam cvf scans (cam04) will be made between 7 and 9.3 micron and 9.2 and 15 micron with a pixel field of view of 6 arcsec. the broad band and cvf observations on this source are concatenated. for two sources (ag car and hd87643) the circumstellar environment will be studied in more detail spectroscopically using sws (aot sws06) around the co and no fundamental lines. these spectra will be taken at specific positions in the nebulae around these stars. the scans wil run from 4.3 to 6.0 micron. the s/n ratios expected for the cam images is between 50 and 100. the s/n ratios for the sws scan is expected to be around 5 in the continuum, but probably is higher in the emission lines.
Instrument
CAM01 , SWS06
Temporal Coverage
1996-02-17T12:13:25Z/1996-11-07T18:34:56Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the worlds 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.
European Space Agency, Trams et al., 1999, 'The circumstellar environment of evolved massive stars ', 1.0, European Space Agency, https://doi.org/10.5270/esa-hzmzr8p
