Triton's streaks as windblown dust

摘要: THE encounter of the Voyager 2 spacecraft with Neptune's satellite Triton revealed many 'dark' (about 10–20% darker than adjacent frost) surface streaks in Triton's southern hemisphere1, resembling that are due to windblown dust on Mars2. It seems therefore transport by winds tenuous atmosphere is required, main question being mechanism for raising from or sub-surface. The two obvious candidates geyser-like eruptions and direct lofting winds1. Here we show that, despite (16±3 µbar) atmosphere3, low-cohesion grains diameters ≲5 µm, may be carried into suspension aeolian shear stress, given expected geostrophic wind speeds4 ∼l0ms-1. (The velocities needed lift as cohesive those found Earth, however, implausibly high.) For erupting plumes, dust-settling timescales yield streak length scales good agreement observed. Both candidate mechanisms seem consistent present observations Triton.