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Gaia20fnr: A binary-lens microlensing event with full orbital motion revealed by four space telescopes

Fuente: arXiv

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Bibliographic Details
Main Authors:	Wicker, M., Wyrzykowski, Ł., Hundertmark, M., Rybicki, K. A., Zieliński, P., Stonkutė, E., Ihanec, N., Maskoliūnas, M., Bachelet, E., Kruszyńska, K., Dominik, M., Buckley, D. A. H., Gezer, I., Gromadzki, M., Mikołajczyk, P., Kotysz, K., Majumdar, J., Pakštienė, E., Zdanavičius, J., Čepas, V., Jonauskaitė, U., Bozza, V., Cassan, A., Jaimes, R. Figuera, Rabus, M., Rota, P., Street, R. A., Tsapras, Y., Wambsganss, J., Awiphan, S., Brincat, S. M., Budzik, Z., Davidson Jr., J. W., Dymock, R., Galdies, C., Godunova, V., Hambsch, F. -J., Jabłonska, M., Kvernadze, T., Larma, M., Makowska, M., Markus, Y., Merc, J., Michniewicz, O., Motylinski, M., Popowicz, A., Radziwonowicz, M., Reichart, D., Simon, A. O., Trzcionkowski, P., Zejmo, M., Zola, S.
Format:	Preprint
Published:	2026
Subjects:	Solar and Stellar Astrophysics
Online Access:	Acceder al recurso
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_version_	1866915755012915200
author	Wicker, M. Wyrzykowski, Ł. Hundertmark, M. Rybicki, K. A. Zieliński, P. Stonkutė, E. Ihanec, N. Maskoliūnas, M. Bachelet, E. Kruszyńska, K. Dominik, M. Buckley, D. A. H. Gezer, I. Gromadzki, M. Mikołajczyk, P. Kotysz, K. Majumdar, J. Pakštienė, E. Zdanavičius, J. Čepas, V. Jonauskaitė, U. Bozza, V. Cassan, A. Jaimes, R. Figuera Rabus, M. Rota, P. Street, R. A. Tsapras, Y. Wambsganss, J. Awiphan, S. Brincat, S. M. Budzik, Z. Davidson Jr., J. W. Dymock, R. Galdies, C. Godunova, V. Hambsch, F. -J. Jabłonska, M. Kvernadze, T. Larma, M. Makowska, M. Markus, Y. Merc, J. Michniewicz, O. Motylinski, M. Popowicz, A. Radziwonowicz, M. Reichart, D. Simon, A. O. Trzcionkowski, P. Zejmo, M. Zola, S.
author_facet	Wicker, M. Wyrzykowski, Ł. Hundertmark, M. Rybicki, K. A. Zieliński, P. Stonkutė, E. Ihanec, N. Maskoliūnas, M. Bachelet, E. Kruszyńska, K. Dominik, M. Buckley, D. A. H. Gezer, I. Gromadzki, M. Mikołajczyk, P. Kotysz, K. Majumdar, J. Pakštienė, E. Zdanavičius, J. Čepas, V. Jonauskaitė, U. Bozza, V. Cassan, A. Jaimes, R. Figuera Rabus, M. Rota, P. Street, R. A. Tsapras, Y. Wambsganss, J. Awiphan, S. Brincat, S. M. Budzik, Z. Davidson Jr., J. W. Dymock, R. Galdies, C. Godunova, V. Hambsch, F. -J. Jabłonska, M. Kvernadze, T. Larma, M. Makowska, M. Markus, Y. Merc, J. Michniewicz, O. Motylinski, M. Popowicz, A. Radziwonowicz, M. Reichart, D. Simon, A. O. Trzcionkowski, P. Zejmo, M. Zola, S.
contents	The microlensing event Gaia20fnr is a long-duration, non-caustic-crossing binary-lens event at high Galactic latitude. Triggered by a photometric rise detected by the Gaia space mission, the event was followed up with observations from multiple ground-based facilities and four space telescopes: Gaia, NEOWISE, Swift, and TESS. We characterize the Gaia20fnr microlensing system by determining the physical and orbital properties of the binary lens, the nature of the luminous source, and the kinematics of both the source and the lens. We employed a binary-lens microlensing model including full Keplerian orbital motion and annual microlens parallax to fit the photometric data. The event is best explained by a K2 giant source at $D_{\rm S} = 3.10 \pm 0.10\,\mathrm{kpc}$ lensed by a stellar binary composed of $M_{\rm L,1} = 0.46 \pm 0.06\,M_\odot$ and $M_{\rm L,2} = 0.52 \pm 0.06\,M_\odot$ at a distance of $D_{\rm L} = 0.54 \pm 0.05\,\mathrm{kpc}$. The light curve exhibits strong signatures of orbital motion and requires a full Keplerian model with a period of $P = 0.67 \pm 0.04\,\mathrm{yr}$ and a radial-velocity semi-amplitude of $K_1 = 16.9 \pm 0.9\,\mathrm{km\,s^{-1}}$. Gaia20fnr is one of the few microlensing events for which a complete Keplerian binary-lens solution has been derived. The model can be tested with follow-up radial-velocity and high-resolution imaging observations as well as forthcoming Gaia DR4 and DR5 astrometric time-series data. Its long duration, multi-peak structure, and extensive coverage make it a benchmark for studying faint nearby low-mass binaries through microlensing.
format	Preprint
id	arxiv_https___arxiv_org_abs_2601_15969
institution	arXiv
publishDate	2026
record_format	arxiv
spellingShingle	Gaia20fnr: A binary-lens microlensing event with full orbital motion revealed by four space telescopes Wicker, M. Wyrzykowski, Ł. Hundertmark, M. Rybicki, K. A. Zieliński, P. Stonkutė, E. Ihanec, N. Maskoliūnas, M. Bachelet, E. Kruszyńska, K. Dominik, M. Buckley, D. A. H. Gezer, I. Gromadzki, M. Mikołajczyk, P. Kotysz, K. Majumdar, J. Pakštienė, E. Zdanavičius, J. Čepas, V. Jonauskaitė, U. Bozza, V. Cassan, A. Jaimes, R. Figuera Rabus, M. Rota, P. Street, R. A. Tsapras, Y. Wambsganss, J. Awiphan, S. Brincat, S. M. Budzik, Z. Davidson Jr., J. W. Dymock, R. Galdies, C. Godunova, V. Hambsch, F. -J. Jabłonska, M. Kvernadze, T. Larma, M. Makowska, M. Markus, Y. Merc, J. Michniewicz, O. Motylinski, M. Popowicz, A. Radziwonowicz, M. Reichart, D. Simon, A. O. Trzcionkowski, P. Zejmo, M. Zola, S. Solar and Stellar Astrophysics The microlensing event Gaia20fnr is a long-duration, non-caustic-crossing binary-lens event at high Galactic latitude. Triggered by a photometric rise detected by the Gaia space mission, the event was followed up with observations from multiple ground-based facilities and four space telescopes: Gaia, NEOWISE, Swift, and TESS. We characterize the Gaia20fnr microlensing system by determining the physical and orbital properties of the binary lens, the nature of the luminous source, and the kinematics of both the source and the lens. We employed a binary-lens microlensing model including full Keplerian orbital motion and annual microlens parallax to fit the photometric data. The event is best explained by a K2 giant source at $D_{\rm S} = 3.10 \pm 0.10\,\mathrm{kpc}$ lensed by a stellar binary composed of $M_{\rm L,1} = 0.46 \pm 0.06\,M_\odot$ and $M_{\rm L,2} = 0.52 \pm 0.06\,M_\odot$ at a distance of $D_{\rm L} = 0.54 \pm 0.05\,\mathrm{kpc}$. The light curve exhibits strong signatures of orbital motion and requires a full Keplerian model with a period of $P = 0.67 \pm 0.04\,\mathrm{yr}$ and a radial-velocity semi-amplitude of $K_1 = 16.9 \pm 0.9\,\mathrm{km\,s^{-1}}$. Gaia20fnr is one of the few microlensing events for which a complete Keplerian binary-lens solution has been derived. The model can be tested with follow-up radial-velocity and high-resolution imaging observations as well as forthcoming Gaia DR4 and DR5 astrometric time-series data. Its long duration, multi-peak structure, and extensive coverage make it a benchmark for studying faint nearby low-mass binaries through microlensing.
title	Gaia20fnr: A binary-lens microlensing event with full orbital motion revealed by four space telescopes
topic	Solar and Stellar Astrophysics
url	https://arxiv.org/abs/2601.15969