7349 20250116202021.0 POSTER-2025-0023 Dileep, Athul Ground- and space-based investigation of the intermediate-age open star cluster NGC 2126 2024 2024-07-15 We performed ground-based, time-series observations of the intermediate-age open cluster NGC 2126 with the 1.3-meter Devasthal Fast Optical Telescope (ARIES) and discovered 112 variable stars in an 18 x 18 arcmin field. Among these, 11 stars were known variables, for which we performed TESS full-frame image photometry in three different sectors. There were 17 new member variables and 84 variable field stars. The eclipsing binary V551 Aur is a member of NGC 2126 with high probability and has a pulsating component. This star was studied in detail by means of a medium-resolution spectrum and TESS photometry. The light curve was analyzed using a binary model, which was then removed to investigate the pulsational variability. The new variable members were classified based on their position in the HR diagram, shape of the phase-folded light curves, period and amplitude of variability. We also modeled the light curves of other binary stars in the field to determine their orbital parameters. NO Joshi, Santosh Lata, Sneh Lampens, Patricia Zúñiga Fernández, Sebastián De Cat, Peter Mkrtichian, David TESS8/KASC15 Workshop, Porto, Portugal peter.decat@ksb-orb.be 1741510 http://publi2-as.oma.be/record/7349/files/Dileep2024_TkasConfE_90.pdf 20168 http://publi2-as.oma.be/record/7349/files/Dileep2024_TkasConfE_90.gif?subformat=icon icon 23150 http://publi2-as.oma.be/record/7349/files/Dileep2024_TkasConfE_90.jpg?subformat=icon-180 icon-180 CPOSTER