We will discuss joint early-time observations from TESS and HST, probing the close-in circumstellar environment of SN 2020fqv - a nearby hydrogen-rich core-collapse supernova (CCSN). Leading up to a CCSN, massive stars like the progenitor of SN2020fqv can undergo significant mass loss and create a circumstellar medium (CSM). After the explosion, the SN shock crashes into the CSM converting some kinetic energy into light, causing the SN to brighten faster than it would otherwise. Thus, observing this early evolution of the SN can give valuable insights into the final stages of mass loss. The exquisite high cadence lightcurve of TESS, captures the rise of 2020fqv allowing us to precisely determine the explosion time and model the progenitor star, along with the surrounding CSM. We also triggered our ultra-rapid target-of-opportunity program with HST to obtain very early-time ultraviolet (UV) spectra of this SN, which showed spectroscopic signatures of CSM interactions. This joint analysis of data from TESS, and HST provides more evidence that the final years of red supergiant can be dramatic, and that early observations like those provided by TESS are key to understanding the CSM surrounding CCSNe.

{"references": ["Morozova et al. (2015)", "Morozova et al. (2018)", "Morozova et al. (2020)", "Vallely et al. (2021)", "Jerkstrand et al. (2014)", "Jerkstrand et al. (2018)", "Gal-Yam et al. (2014)", "Wu and Fuller (2021)", "Fuller (2017)", "Quataert and Shiode (2017)", "Bowen (1935)"]}