ASAS-SN has discovered a 13th mag. star undergoing a fading event (see ATel).
ASASSN-25cd lies in Sagittarius.
The linear fading trend and the previous lack of variability suggest it might be a long period eclipsing binary. The star stayed constant in previous years of ASAS-SN data (2016-2025) and also in ASAS-3 data (2000-2009).
It is a K-type giant so it might be an EA/GS.
It seems to have reached a minimum magnitue of 15.0 g but we need more data to see if that is indeed the bottom of the “eclipse”.
In EA/GS systems, amplitude varies strongly depending on passband, because a late type star is usually eclipsing a hotter brighter object.
We now only have ASAS-SN g data. It would be interesting to have multicolor photometry to see if the amplitudes are indeed that different.
Observations are welcomed!
We will ask the Sequence Team for a sequence.
Cheers,
Sebastian
