Updates from the EREBOS Project: the First Deeply-Eclipsing Hot Subdwarf Binary

Planets and brown dwarfs in close orbits around main sequence stars will interact with their stellar hosts once they ascend the red giant branch. The details of these interactions and their outcomes are currently unclear. Discoveries of brown dwarfs orbiting post-red giant branch "hot subdwarf" stars imply that (i) the angular momentum resident in an orbiting substellar object is sufficient for ejecting the outer layers of a red giant's atmosphere and (ii) the substellar object can survive this interaction. More than 120 eclipsing hot subdwarf binaries with cool, low-mass companions were recently discovered from light curves obtained by the OGLE and ATLAS projects, increasing the number known by nearly a factor of ten. The Eclipsing Reflection Effect Binaries from Optical Surveys (EREBOS) project aims to obtain follow-up spectroscopy and determine the stellar masses in all these systems. The companion mass distribution resulting from this work will allow us to determine whether there is a lower mass limit for substellar objects to eject a red giant's envelope and survive engulfment, as suggested by theory. Here we give a brief overview of the EREBOS project and discuss progress towards this goal, including the discovery of a deeply eclipsing hot subdwarf + red dwarf binary. This material is based in part upon work supported by the National Science Foundation under Grant No. AST-1812874.