Description |
Stars form from contracting molecular cloud cores, but this process relies heavily on the ability of the core to cool and to overcome the magnetic barrier; this, in turn, depends on the chemical composition and could therefore lead to drastically different outcomes at low metallicity. However, most of what we know about star formation is derived from studies of solar-metallicity YSOs in the Milky Way. To investigate the role of metallicity on the star-formation process we propose to observe a sample of early-stage massive young stellar objects in the metal-poor Small and Large Magellanic Clouds. These were selected from among sources with spectroscopic evidence of ice and/or maser emission, and comprise a range in luminosity. We propose to use PACS and SPIRE FTS to measure the strengths of key atomic and molecular lines, in order to measure the temperature, density, ionization state and abundances of the main cooling species in these objects. By comparing the SMC and LMC samples, and Galactic samples of YSOs, we will assess the effect of the reduced metallicity on the formation process of massive stars. |