GCN Circular 46177

Subject

EP-WXT trigger 01709322274: Ondrejov D50 detection of a likely stellar flare

Date

2026-11-06T22:20:12Z (a day ago)

Edited On

2026-11-06T23:05:27Z (a day ago)

From

Filip Novotný at Masaryk University <filip.novotny@talentovani.cz>

Edited By

Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Filip Novotný at Masaryk University <filip.novotny@talentovani.cz>

Via

Web form

F. Novotny, J. Strobl, M. Jelinek and R. Hudec (ASU CAS Ondrejov) report:

We observed the position of the Einstein Probe WXT trigger 01709322274
(T0 = 2026-11-06 21:28:37 UT; RA, Dec = 46.972, +24.975, err 3.1 arcmin)
with the D50 telescope of the Astronomical Institute Ondrejov, near
Prague, Czech Republic. We obtained 10 unfiltered images, each a sum of
100x1.1 s exposures, between 21:43:37 and 22:02:13 UT (T0+15 min to
T0+34 min). Observations are continuing.

We detect a fading high proper motion M dwarf 1.5 arcmin from the WXT
position, at

RA, Dec = 03:07:47.32, +24:57:51.9 


The star is well detected in single images and fades steadily throughout
our sequence, from 13.15 to 13.27 mag (0.44 +/- 0.04 mag/h, residual rms
0.013 mag) in RC. Field stars of similar brightness are constant to within
0.01-0.02 mag. No other M-dwarf-coloured star in our field varies
significantly, and this star is the brightest and highest proper motion
M dwarf in the field.

Photometry is unfiltered, calibrated against ATLAS-RefCat2
stars, and not corrected for Galactic extinction.