IAASARS Seminar: Dr. Terese Thidemann Hansen: The R-Process Alliance: Hunting for Gold скачать в хорошем качестве

IAASARS Seminar: Dr. Terese Thidemann Hansen: The R-Process Alliance: Hunting for Gold

____________________________________________________________________________________________________________________________________________________________ Monday, October 14 at 12:30 EEST Dr. Terese Thidemann Hansen, Stockholm University, Sweden Title: The R-Process Alliance: Hunting for Gold (or, more realistically, uranium) Abstract: Heavy elements like silver, gold, and uranium are produced via the rapid neutron-capture (r-)process. This process only occurs in rare explosive events in the Universe like supernovae (SNe) and neutron star mergers (NSMs), making it highly challenging for astronomers to gather direct observations of the element creation. Likewise, it is difficult for nuclear physicists to recreate and study the nuclear process in the laboratory. These obstacles are why we today, six decades after the theoretical prediction of the r-process, still do not know how or where in the Universe gold and silver are made. However, in 2017, the R-Process Alliance (RPA) initiated a successful new search to uncover bright metal-poor halo stars enriched with r-process elements. These stars are invaluable laboratories for studying the r-process as the gas from which these stars formed was polluted by at most a few enrichment events --- perhaps even a single explosion. The RPA has collected spectra of ~2000 stars and discovered over 70 new highly r-process enhanced. I will report on RPA efforts over the past six years and outline plans for the future, including ways this stellar sample will help constrain the astrophysical site(s) of the r-process. I will also discuss recent detections of r-process-enhanced stars in Milky Way satellites and streams, where these stars have been detected in several systems, allowing us to study the environment where the r-process occurred. _____________________________________________________________________________________________________________________________________________________________