The Polytropic Index of Interplanetary Coronal Mass Ejections near L1 C. Katsavrias, G. Nicolaou, G. Livadiotis, A. Vourlidas, L. B. Wilson III and I. Sandberg A&A, 695 (2025) A146 Published online: 14 March 2025 DOI: 10.1051/0004-6361/202452984