Contact
smartell@aao.gov.au
Australian Astronomical Observatory
167 Vimiera Rd
Marsfield, NSW 2122
Australia
+61 (02) 9372 4885
Sarah Martell
I am a Research Fellow working at the Australian Astronomical Observatory in Sydney, Australia. I use moderate-resolution spectroscopy from Keck Observatory, Lick Observatory and the Very Large Telescope to study the compositions of stars in globular clusters, some of the oldest stars in the Milky Way, and to compare them to star clusters in nearby dwarf galaxies. Since globular cluster stars formed at the very beginning of our galaxy's lifetime, we can use their properties to reconstruct the early history of the Milky Way. Roughly half of the stars in globular clusters have an unusual abundance pattern in the elements carbon, nitrogen, oxygen, sodium, magnesium and aluminum, indicating that star formation in clusters in the early Galaxy happened quickly and at high density.
As a postdoctoral researcher at the University of Heidelberg, which is a partner in the Sloan Digital Sky Survey, I searched through the SEGUE database of moderate-resolution spectra for stars with globular cluster-like abundance patterns in the extended stellar halo of the Galaxy, in order to understand how much of the halo is made up of dissolved star clusters. I am currently expanding on that work, using high-resolution spectroscopy from the Hobby-Eberly Telescope and Keck Observatory to get a clearer picture of the elemental abundances in these rare immigrant stars.