we propose to study circumstellar envelopes in the newly discovered dwarf spheroidal sgr. it is the nearest extra-galactic system (half the distance to the lmc) and is the only old, metal-poor stellar population where we can study in detail the mass-loss process. the relatively simple star-formation and chemical history will allow us to measure the mass-loss efficiency for a narrow range in metallicity and stellar age, and will provide a crucial comparison sample compared to the younger, more metal-rich magellanic clouds. we will carry out mid-infrared photometry to detect circumstellar envelopes and measure the mass-loss rate. we will also observe the two planetary nebulae with sws, to measure accurate abundances. both planetary nebulae in sgr have [wc]-like central stars, indicating an unexpected difference in stellar population with the galactic halo.
Instrument
CAM01 , SWS02
Temporal Coverage
1997-03-16T12:14:16Z/1997-03-27T09:21:53Z
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.
European Space Agency, 1999, Carbon Stars And Square_Bracket_Openwcsquare_Bracket_Close-Planetary Nebulae In The Sagittarius Dwarf Spheroidal Galaxy, 1.0, European Space Agency, https://doi.org/10.5270/esa-4plkil5
