<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">The next SU astronomy departmental seminar will take place on <b class="">Friday September 16th at 10:30 in room FC 61</b> (AlbaNova building, 6th floor) and on zoom.<br class=""><br class="">---------------------------------------------------------------------------------------------------------------------------------<br class=""><br class=""><b class="">Speaker: Avishai Gilkis - Tel Aviv University<br class="">Title: Uncertainty in envelope removal of core-collapse supernova progenitors<br class=""></b><br class="">Abstract: <div class="">The theoretical modeling of massive star evolution is riddled with uncertainties. Two such unresolved aspects are mass loss by stellar winds and mixing in stellar interiors. In my talk I will discuss the implications of these uncertainties on reconciling theory with observations of massive stellar endpoints. In the first part I will present the role of winds for progenitors of stripped-envelope supernovae. While it is commonly assumed that binary interaction removes the hydrogen envelope, the assumed post-interaction mass-loss rate is crucial for the resulting supernova type. I will show how we assess the hydrogen mass in stripped-envelope supernova progenitors by comparing pre-supernova photometry with evolution models. In the second part of the talk I will focus on the lack of observed cool and very luminous supergiant stars, an unexplained phenomenon termed the “Humphreys-Davidson Limit”, which is in contrast to simulations of evolved massive stars. I will show how enhanced mixing above convective cores can aid in removing the hydrogen envelope and ease the tension between theory and observations for such stars at the high-mass end, which are also thought to be the progenitors of merging black holes.<br class=""><br class="">---------------------------------------------------------------------------------------------------------------------------------<br class=""><br class="">We look forward to seeing many of you there. Thanks!<br class=""><br class="">Eliot and Kris<br class=""><br class=""><br class="">Topic: Astronomy Department Seminar Gregor Traven<br class="">Time: Sept 9, 2022 10:30 AM Stockholm<br class=""><br class="">Join Zoom Meeting:<br class=""><a href="https://stockholmuniversity.zoom.us/s/61002076352" class="">https://stockholmuniversity.zoom.us/s/61002076352</a><br class=""><br class="">Meeting ID: 610 0207 6352</div></body></html>