American Association of Variable Star Observers (AAVSO)
Mon, 06/27/2022 - 18:16

Matthias Kolb called my attention to this very interesting object in Chamaleon that behaved as a normal mira-type star until 2012 and then had a symbiotic nova outburst.
The nature of the object was found in 2020 by L. Lancaster and collaborators but had been missed in VSX until now (Thanks Matthias!).

Compare the previous mira behaviour in ASAS-3 data with the ASAS-SN observations showing the outburst long maximum and fading.

ASAS-SN magnitudes at maximum were saturated and they were corrected by comparing ASAS-SN light curves of similar magnitude stars with non saturated GCPD/Hipparcos data. They are consistent with good coverage of the outburst now available through Gaia DR3.
The star peaked at V= 7.4 between July and September 2015. It has remained at 10th magnitude for the last 3 years.

The rise to maximum was only covered by a couple of APASS observations, the fact that it was so bright and that it happened after ASAS-3 and before ASAS-SN made it difficult to detect.
We missed a 7th mag. nova!

Observations are encouraged to see its future development and when the mira pulsations will come back (and if the period has changed). It may still take many years though.

VSX information.