ASASSN-21uh: most likely an AM CVn object with a WZ Sge-type superoutburst or a WZ Sge object with type-E rebrightenings

Taguchi-san found that ASASSN-21uh had a temporary dip a week after the outburst by using ZTF data (ALeRCE) and ASAS-SN data. This object is most likely an AM CVn object with a WZ Sge-type superoutburst or a WZ Sge object with type-E rebrightenings. Spectroscopy is encouraged.

ALeRCE: https://alerce.online/object/ZTF21ackbkbn

ASAS-SN Sky Patrol (20 days): https://asas-sn.osu.edu/sky-patrol/coordinate/ce4f98bb-179e-4b61-8d6b-8d7ce2...

ASAS-SN Sky Patrol (all): https://asas-sn.osu.edu/sky-patrol/coordinate/f25d1265-e2e0-4d06-965d-58ea53...

ASASSN-21uh  ---  ------- 19:34:30.71 47:39:6.9 2021-10-31.18 15.5 SDSS DSS VIZIER -------  CV candidate, matches to PS1 g=20.4, g>18.3 on 2021-10-30.22, g=15.9 on 2021-10-31.19.

IDs: 053741.285 +473906.626 PS1_DR1_165182936280562816 g=20.3844(0.0177) r=--(--) i=--(--) z=20.5024(0.1437) y=--(--) 053744.551 +473909.642 PS1_DR1_165182936289423720 g=--(--) r=21.7877(0.2405) i=--(--) z=--(--) y=19.4201(0.1117) 053741.522 +473906.720 PS1_DR2_165182936280562816 g=22.2087(0.078856) r=22.2866(0.087181) i=23.2862(0.255626) z=25.0042(2.79944) y=21.9475(0.389282)

ASASSN-21uh 20211030.223 <17.247g ASN ASASSN-21uh 20211031.185 15.793g ASN (outburst) ASASSN-21uh 20211031.210 16.218o ATF ASASSN-21uh 20211102.202 16.250zr ZLR ASASSN-21uh 20211102.505 16.10:C Myy ASASSN-21uh 20211103.214 16.137g ASN ASASSN-21uh 20211103.540 16.44C Myy ASASSN-21uh 20211104.159 16.525zr ZLR ASASSN-21uh 20211104.255 16.695o ATF ASASSN-21uh 20211104.438 16.430G GIA ASASSN-21uh 20211104.564 <145C Myy ASASSN-21uh 20211105.172 <16.864g ASN (dip) ASASSN-21uh 20211106.099 18.599zr ZLR ASASSN-21uh 20211106.135 19.281zg ZLR ASASSN-21uh 20211106.268 18.964cy ATF ASASSN-21uh 20211106.551 <167C Myy ASASSN-21uh 20211107.152 16.331g ASN (rebrightening) ASASSN-21uh 20211108.115 16.622zr ZLR ASASSN-21uh 20211108.197 16.841o ATF ASASSN-21uh 20211108.198 16.412zg ZLR ASASSN-21uh 20211108.213 16.785g ASN ASASSN-21uh 20211110.101 16.638g ASN ASASSN-21uh 20211110.198 17.130o ATF

(ASN: ASAS-SN Sky Patrol, ATF: Atlas forced photometry, GIA: Gaia Alerts, Myy: Masayuki Moriyama, ZLR: Zwicky Transient Facility Lasair (Masci+ 2019))