A Search for Gaseous H2O in Asteroids openPar24closePar Themis & openPar65closePar Cybele

The detection of water ice on Asteroids (24) Themis and (65) Cybele and cometlike activity on some asteroids (socalled main belt comets) have recently provided evidence for water ice in the outer asteroid belt. This supports the suggestion that water in the Earths oceans may have been delivered from the outer asteroid belt.In 2010, for both (24) Themis and (65) Cybele, results were published from rotationally resolved nearIR spectra that indicated the presence of widespread ice on their surfaces, a detection which served to imply a wider prevalence of water among minor Solar System bodies. However, this detection has since been challenged in 2011 with an alternative interpretation of the absorption at 3.1 microns being suggested. This proposal requests 2 hours of the Herschel Space Observatorys HIFI instrument scheduling time, 1 hour observation per asteroid, to provide conclusive evidence of the presence of water ice on these asteroids through the detection of outgassing via sublimation of this water; a result which has profound implications on the understanding of the origin of water on our planet. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]