Joint Nuclear Astrophysics Seminar

A galaxy's mean metallicity is usually closely correlated with its luminosity and mass. Consequently the most metal-poor galaxies in the local universe are dwarf galaxies. Late-type dwarf galaxies tend to have experienced low-efficiency, fairly continuous star formation since a Hubble time with amplitude variations of up to a factor of three. Early-type dwarf galaxies are dominated by old and intermediate-age stellar populations while having little gas and typically no active star formation at the present time. This class of objects includes the least luminous, least massive galaxies known - the very metal-deficient, old ultra-faint dwarf spheroidal galaxies that were recently discovered around the Milky Way. Both classes contribute to the build-up of more massive galaxies, albeit in different ways.

Interstellar dust has long been researched by astronomical methods to learn about its size distribution, grain properties and composition. However, interstellar dust grains also move through the solar system. They were detected for the first time in-situ with the Ulysses dust detector in 1993. In addition, in 2006, the Stardust mission returned three interstellar dust grain candidates back to Earth after a collection period of 195 days. In this talk we elaborate on how the current in-situ ISD measurement methods are a valuable addition to the knowledge about interstellar dust inferred from classical astronomy. We also discuss the role of interstellar dust dynamics and simulations herein.