[vsnet-alert 25680] XTE J1829-098 rising

[Denis Denisenko d.v.denisenko@gmail.com via vsnet-alert]

SRG/ART-XC team from IKI (Russian Space Research Institute) reported the
detection of an ongoing activity from X-ray pulsar XTE J1829-098 in Scutum:
A. Shtykovsky et al., 2021, ATel #14521,
https://www.astronomerstelegram.org/?read=14521

Quoting the Telegram, "Although there is a known NIR counterpart (Halpern
and Gotthelf, 2007) for the source, neither the type nor the class of a
secondary star has been defined".

The NIR component is 2MASS J18294455-0951203 (J=8.04+/-0.02, H=6.11+/-0.05,
K=4.98+/-0.03). Gaia magnitude is 16.03(6) in DR2 and 15.93(6) in EDR3.
Nmag in GSC 2.3.2 is 14.46 from the IR DSS plate.

The star is not listed in any catalogs of variables and in VSX. I have
queried the ATLAS forced photometry server (Tonry et al., 2018). The range
of variability is 16.3-19.3o (ATLAS orange filter is essentially r+i).
Light curve: http://scan.sai.msu.ru/~denis/XTEJ1829-098-ATLAS-LC.gif

The period from 4 cycles is 533+/-3 days, and the Epoch of maximum is
MJD=58392. If the period persists, the next maximum should be reached in
early September (around Sep. 01-03). Note there is a local maximum on the
phased light curve at the phase 0.73 followed by nearly a plato lasting
until phase 0.87.

Denis Denisenko