ASASSN-20da
RA 14:50:06.70, DE -65:49:46.9 (J2000.0)
bright transient near the Galactic plane, very unusual light curve,
matches to Gaia DR2 5848963158970287616 (G=12.3), ...
http://www.astronomy.ohio-state.edu/~assassin/transients.html
Complete ASAS-SN Sky Patrol (Shappee et al. 2014ApJ...788...48S
and Kochanek et al. 2017PASP..129j4502K) light curve and data:
https://asas-sn.osu.edu/light_curves/907f56bc-1745-4a11-b09a-2bef7df868…
Almost constant (Vmag. 12.4) in ASAS-3.
Gaia DR2 parallax 1.5565 ± 0.0299 mas (distance 631 ± 12 pc). Common proper motion pair with Gaia DR2 5848962403056043136 (Gmag. 15.0, parallax 1.5999 ± 0.1146 mas, distance 619 ± 48 pc), which is 1.8" to the SSW.
It is unclear which of the two components has brightened. Spectroscopy and precise astrometry are urgently required (multiband as well as time-resolved photometry are encouraged, too).
Clear skies,
Patrick