[vsnet-alert 24104] asassn-20dd, a probable ugwz type object

[Berto Monard astroberto13m@gmail.com via vsnet-alert]

The amplitude of the outburst and a transition period of more than 10d
before modulations hint strongly at an ugwz type outburst.

Several nights of timeseries observations of ASASSN-20dd, done at CBA-KKO
since 17 Mar 2020, have shown no modulation up to last night.
The 22 Mar TS, under partly cloudy conditions, show the OT slightly
brighter with a hint of a 0.3 mag modulation. This is 10d into the reported
outburst.

Visual inspection of the images show the proposed counterpart Gaia DR2
5414848510554631808 (mag 19.5) to be incorrect.

Based on astrometry on 17 Mar images the following coordinates were derived
vs the USNO-B1.0 frame: 10 03 28.62 -44 45 44.6 .
This is not far off the ASASSN given coordinates, but well different from
their indicated counterpart, about 1.5arcsec to the SW of it

As there is no known counterpart for this OT we must assume an outburst
amplitude of more than 5.5 mags.


Further timeseries confirming the above are planned.

Berto Monard / CBA-KKO