A Search for Coronal Activity Among Metal-Poor Subdwarfs

We propose to search for coronal soft xray emission from several of the oldestmain sequence stars in the Galaxy. Our program stars have been preselected fromgroundbased observations to have He I 10830 Ang absorption lines with anequivalent width of 30 mA or more. If such stars follow a relation between He Iequivalent width and soft xray flux applicable to Population I dwarf stars,then they would be expected to have xray luminosities 5e7 times theirbolometric luminosity, and as such would yield detectable sources in 20 ksexposures with the EPICpn camera on XMMNewton. Our proposal seeks to push thedetection of coronal activity to the lowest stellar metallicities yet surveyed,namely Fe/H virgul 2.0 dex. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]