It seems that space age instruments are now finding evidence of water-ice in the many locations we have pointed them to look. The latest to be confirmed includes asteroid 24 Themis. But is it from subsurface reservoirs evaporating (not unlike comets) or is it locally generated by the sputtering of atoms from surface rocks and recombination with the solar wind? Recent data appears to confirm prior measurements indicating the likely presence of water-ice on the surface of asteroid 24 Themis. Read more
(24) Themis Epoch 2007 Oct. 27.0 TT = JDT 2454400.5 Goffin M 328.35947 (2000.0) P Q n 0.17791088 Peri. 107.89566 -0.80788481 -0.58928891 a 3.1308893 Node 35.99891 +0.53556758 -0.73962459 e 0.1319198 Incl. 0.75953 +0.24594612 -0.32510621 P 5.54 H 7.08 G 0.19 U 0