ASASSN-24fa: A Long-Lasting, Deep Dimming Event
ATel #16715; B. JoHantgen, D. M. Rowan, K. Z. Stanek, C. S. Kochanek, S. A. Petz (OSU)
on 17 Jul 2024; 18:26 UT
Credential Certification: Krzysztof Stanek (stanek.32@osu.edu)
Subjects: Optical, Variables
Using data from the All-Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014, Kochanek et al. 2017, Hart et al. 2023 ), we discovered a star with a deep dimming event. ASASSN-24fa (RA = 08h03m26.93s, DEC = -26d16m19.7s, d ~ 4.7 kpc, T_eff = 16,760 K, G = 13.2, BP = 13.2, RP = 13.0, DR3 source_id = 5697179770616369664) is a hot main sequence star in Gaia DR3 (Gaia Collaboration et al., 2023, A&A, 674, A1) with extinction-corrected absolute magnitude M_G=-0.7 mag. ASAS-SN first observed the star on UT 2016-02-03 and it has ~4,700 data points at this time.
ASASSN-24fa had a mean magnitude of g~13.3 (V~13.2). The dipping event began around UT 2022-03-23 and it faded to a magnitude of g~13.6 around UT 2022-11-13. At present it has a magnitude of g~13.5 and has been slowly becoming brighter. This is the only significant dipping event seen in the ASAS-SN data. It is classified as a short-timescale variable in Gaia DR3 (Maiz Apellaniz et al., 2023, A&A, 677, A137) with a period of 0.46 days.
We thank Las Cumbres Observatory and its staff for their continued support of ASAS-SN. ASAS-SN operations are funded in part by the Gordon and Betty Moore Foundation through grants GBMF5490 and GBMF10501 to the Ohio State University, and Alfred P. Sloan Foundation grant G-2021-14192.
