[vsnet-alert 26073] asassn-21mn: probable ugwz star with very faint precursor

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

observations were done at CBA KKO during three nights. The mean magnitude
varied from 14.7 to 15.0 in the period 15/7 to 18/7

After about ten days since the detection asassn-21mn showed clear
superhumps with a period of around 0.052d, but in a peculiar way the shape
of this modulation changed during the following night.

astrometry vs ucac2 from images taken on 15/7 gives a (2000) position 15 52
31.632 -67 00 01.66 +/- 0.2". At that position there is no clear
counterpart on vizier... and the outburst amplitude must be > 7 mag.

very likely another ugwz star, which is now around mag 15

Berto Monard / CBA KKO