On the radius spectrum of solid grains settling in polytropic protoplanets Gour Chandra Paul, Mrinal Chandra Barman and Amitabh Kumer Halder Eur. Phys. J. Plus, 139 7 (2024) 605 Published online: 10 July 2024 DOI: 10.1140/epjp/s13360-024-05361-2