SF2A-2021: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics. Eds.: A. Siebert, K. Baillié, E. Lagadec, N. Lagarde, J. Malzac, J.-B. Marquette, M. N'Diaye, J. Richard, O. Venot, 2021, pp.331-334 SF2A-2021: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics SF2A-2021: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics, A. Siebert, K. Baillié, E. Lagadec, N. Lagarde, J. Malzac, J.-B. Marquette, M. N'Diaye, J. Richard, O. Venot, Jun 2021, Online, France. pp.331-334