Publikationsdatum:
2016-05-05
Beschreibung:
This study provides the first observations of Plutogenic ions and their unique interaction with the solar wind. We find ~20% solar wind slowing that maps to a point only ~4.5 R P upstream of Pluto and a bow shock most likely produced by comet-like mass loading. The Pluto obstacle is a region of dense heavy ions bounded by a “Plutopause” where the solar wind is largely excluded, and which extends back 〉100 R P into a heavy ion tail. The upstream standoff distance is at only ~2.5 R P . The heavy ion tail contains considerable structure, may still be partially threaded by the IMF, and is surrounded by a light ion sheath. The heavy ions (presumably CH 4 + ) have average speed, density, and temperature of ~90 km s -1 , ~0.009 cm -3 , and ~7x10 5 K, with significant variability, slightly increasing speed/temperature with distance and are N-S asymmetric. Density and temperature are roughly anti-correlated yielding a pressure ~2 x10 -2 pPa, roughly in balance with the interstellar pickup ions at ~33 AU. We set an upper bound of 〈30 nT surface field at Pluto and argue that the obstacle is largely produced by atmospheric thermal pressure like Venus and Mars; we also show that the loss rate down the tail (~5 x10 23 s -1 ) is only ~1% of the expected total CH 4 loss rate from Pluto. Finally, we observe a burst of heavy ions upstream from the bow shock as they are becoming picked up and tentatively identify an IMF outward sector at the time of the NH flyby.
Print ISSN:
0148-0227
Thema:
Geologie und Paläontologie
,
Physik
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