Impact induced surface heating by planetesimals on early Mars T. I. Maindl, R. Dvorak, H. Lammer, M. Güdel, C. Schäfer, R. Speith, P. Odert, N. V. Erkaev, K. G. Kislyakova and E. Pilat-Lohinger A&A, 574 (2015) A22 Published online: 19 January 2015 DOI: 10.1051/0004-6361/201424256