AT2021uey: A planetary microlensing event outside the Galactic bulge

May 2025 • 2025A&A...697A..57B

Authors • Ban, M. • Voloshyn, P. • Adomavic̆ienė, R. • Bachelet, E. • Bozza, V. • Brincat, S. M. • Bruni, I. • Burgaz, U. • Carrasco, J. M. • Cassan, A. • C̆epas, V. • Cusano, F. • Dennefeld, M. • Dominik, M. • Dubois, F. • Figuera Jaimes, R. • Fukui, A. • Galdies, C. • Garofalo, A. • Hundertmark, M. • Ilyin, I. • Kruszyńska, K. • Kulijanishvili, V. • Kvernadze, T. • Logie, L. • Maskoliūnas, M. • Mikołajczyk, P. J. • Mróz, P. • Narita, N. • Paks̆tienė, E. • Peloton, J. • Poleski, R. • Qvam, J. K. T. • Rau, S. • Rota, P. • Rybicki, K. A. • Street, R. A. • Tsapras, Y. • Vanaverbeke, S. • Wambsganss, J. • Wyrzykowski, Ł. • Zdanavic̆ius, J. • Żejmo, M. • Zieliński, P. • Zola, S.

Abstract • We report the analysis of a planetary microlensing event AT2021uey. The event was observed outside the Galactic bulge and alerted both space-(Gaia) and ground-based (ZTF and ASAS-SN) surveys. From the observed data, we find that the lens system is located at a distance of ∼1 kpc and comprises an M-dwarf host star of about half a solar mass, orbited by a Jupiter-like planet beyond the snowline. The source star could be a metal-poor giant located in the halo according to the spectral analyses and modelling. Hence, AT2021uey is a unique example of the binary-lens event outside the bulge that is offered by a disc-halo lens-source combination.

Links

• POSTSCRIPT https://www.aanda.org/10.1051/0004-6361/202554236/postscript
• PDF https://www.aanda.org/10.1051/0004-6361/202554236/pdf
• PREPRINT http://arxiv.org/abs/2503.22331
• ELECTR https://doi.org/10.1051%2F0004-6361%2F202554236