BEGIN:VCALENDAR
VERSION:2.0
PRODID:icalendar-ruby
CALSCALE:GREGORIAN
METHOD:PUBLISH
BEGIN:VEVENT
DTSTAMP:20240328T133846Z
UID:https://www.mps.mpg.de/events/15531/2169
DTSTART:20181001T090000Z
DTEND:20181001T100000Z
CLASS:PUBLIC
CREATED:20180925T123135Z
DESCRIPTION: On 14 July 2015\, NASA’s New Horizons spacecraft observed an
ultraviolet solar occultation of Pluto's atmosphere with its Alice ultrav
iolet spectrograph and performed a radio occultation that probed Pluto's a
tmosphere down to the surface (Hinson et al.\, Icarus\, 290\, doi.org/10.1
016/j.icarus.2017.02.031\, 2017). The previously published results of most
interest in this talk are 1) peak temperature of ~ 106 K at ~ 25 km\, 2)
cold isothermal temperature ~ 65-68 K in Pluto’s upper atmosphere\, 3) i
nferred CH4 surface mixing ratio ~ 0.3±0.02%\, and 4) inferred
enhanced Jeans escape rates are 3-7 x 1022 N2 s-1 and 4-8 x 1025 CH4 s-1 at the e
xobase (r ~ 2900 km\, where the Kn = 0.7). I address the questions: 1) is
the atmosphere spherically symmetric\, 2) thickness of the planetary bound
ary layer\, and 3) time constants governing the chemistry\, diffusion\, an
d escape of N2 and CH4. Given the length of these ti
me constants\, how do you interpret NH flyby data taken in a time interval
much shorter than these time constants\, some of which exceed the duratio
n of the flight time to Pluto. Escaping CH4 takes approximately
1 Earth year to reach the edge of Pluto’s Hill sphere. In spite of this
I calculate the slowing down of the solar wind detected by the NH’s SWA
P instrument.\nSpeaker: Darell Strobel
LAST-MODIFIED:20181001T072416Z
LOCATION:MPS\, Room: Auditorium
ORGANIZER:Urs Mall
SUMMARY:Planetary Group Seminar: The Atmosphere of Pluto observed by the Ne
w Horizons as seen by a Theorist (D. Strobel)
URL:https://www.mps.mpg.de/events/15531/2169
END:VEVENT
END:VCALENDAR