ASASSN-24fw is a F-type main-sequence star that underwent a rare, prolonged occultation event detected by the All Sky Automated Survey for SuperNovae (ASAS-SN), resulting in a deep dimming of approximately 4.1 magnitudes in the g-band lasting about 8–9 months from late September 2024 to late May or June 2025.
Observation The star is located approximately 3,260 light-years away in the constellation of Monoceros. It has an estimated mass of about 1.4 and exhibits an infrared excess indicative of circumstellar dust, with pre-event photometry showing stability over more than a decade of ASAS-SN monitoring.
One model attributes the occultation to optically thick rings or a circumplanetary disk surrounding either a red dwarf or a substellar companion (brown dwarf or massive gas giant, minimum mass around 3–3.4 ), with ring radius ~0.17 AU forming a large structure at ~14 AU orbital separation.
See also List of stars that have unusual dimming periods
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