ASASSN-24fw: Candidate Gas-rich Circumsecondary Disk Occultation of a Main-sequence Star
Dusty disks around planetary and substellar companions in outer reaches of exoplanetary systems can be detected as long-lasting occultations, provided the observer is close to the secondary's orbital plane. Here we report optical spectroscopy with KOSMOS (Apache Point Observatory), MagE (Magellan), and GHOST (Gemini-S) of ASASSN-24fw (Gaia 07:05:18.97+06:12:19.4), a 4 mag dimming event of a main-sequence star which lasted 8.5 months. We discover multiple low-ionization metal emission lines with velocity dispersion ≲ 10 km s−1 blueshifted by 27 km s−1 with respect to the star, as well as kinematically complex Na D absorption.









