J/A+A/617/L5 Water delivery in Pluto and Triton atmospheres (Poppe+, 2018)
Interplanetary dust delivery of water to the atmospheres of Pluto and Triton.
Poppe A.R., Horanyi M.
<Astron. Astrophys. 617, L5 (2018)>
=2018A&A...617L...5P 2018A&A...617L...5P (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Planets
Keywords: meteorites, meteors, meteoroids -
Kuiper belt objects: individual: Pluto -
planets and satellites: individual: Triton -
planets and satellites: atmospheres - zodiacal dust
Abstract:
Both Pluto and Triton possess thin, N2-dominated atmospheres
controlled by sublimation of surface ices.
We aim to constrain the influx and ablation of interplanetary dust
grains into the atmospheres of both Pluto and Triton in order to
estimate the rate at which oxygen-bearing species are introduced into
both atmospheres.
We use (i) an interplanetary dust dynamics model to calculate the flux
and velocity distributions of interplanetary dust grains relevant for
both Pluto and Triton and (ii) a model for the ablation of
interplanetary dust grains in the atmospheres of both Pluto and
Triton. We sum the individual ablation profiles over the incoming mass
and velocity distributions of interplanetary dust grains in order to
determine the vertical structure and net deposition of water to both
atmospheres.
Our results show that <2% of silicate grains ablate at either Pluto or
Triton while approximately 75% and >99% of water ice grains ablate at
Pluto and Triton, respectively. From ice grains, we calculate net
water influxes to Pluto and Triton of ∼3.8kg/d
(8.5x103H2O/cm2/s) and ∼370kg/d (6.2x105H2O/cm2/s),
respectively. The significant difference in total water deposition
between Pluto and Triton is due to the presence of Triton within
Neptune's gravity well, which both enhances interplanetary dust
particle (IDP) fluxes due to gravitational focusing and accelerates
grains before entry into Triton's atmosphere, thereby causing more
efficient ablation.
We conclude that water deposition from dust ablation plays only a
minor role at Pluto due to its relatively low flux. At Triton, water
deposition from IDPs is more significant and may play a role in the
alteration of atmospheric and ionospheric chemistry. We also suggest
that meteoric smoke and smaller, unablated grains may serve as
condensation nuclei for the formation of hazes at both worlds.
Description:
Figure 4 shows the mass deposition profile as a function of altitude,
separated by object and dust family.
Figure 5 shows the interplanetary dust grain mass flux, Pluto's
surface atmospheric pressure from the models of Bertrand & Forget
(2017, Icarus, 287, 72), and Pluto's heliocentric distance as a
function of time over one Pluto year.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
figure4.dat 54 1800 Data for Figure 4, ablation rate vs. height
figure5.dat 76 1000 Data for Figure 5, Pluto variables vs time
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See also:
J/ApJ/724/L84 : Changes in Titan's atmosphere from Cassini (Teanby+, 2010)
J/ApJS/191/96 : Titan IR spectra & optical cst of nitrile ices (Moore+, 2010)
Byte-by-byte Description of file: figure4.dat
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Bytes Format Units Label Explanations
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1- 10 E10.5 km Alt Altitude
12- 21 E10.5 g/s/km EKBP Ablation rate from EKB (Edgeworth-Kuiper Belt)
in Pluto atmosphere
23- 32 E10.5 g/s/km OCCP Ablation rate from OCC (Oort-Cloud Comets)
in Pluto atmosphere
34- 43 E10.5 g/s/km EKBT Ablation rate from EKB (Edgeworth-Kuiper Belt)
in Triton atmosphere
45- 54 E10.5 g/s/km OCCT Ablation rate from OCC (Oort-Cloud Comets)
in Triton atmosphere
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Byte-by-byte Description of file: figure5.dat
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Bytes Format Units Label Explanations
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1- 10 E10.5 yr Time Time
12- 21 E10.5 AU HDP Pluto heliocentric distance
23- 32 E10.5 g/m2/s EKBM EKB mass flux
34- 43 E10.5 g/m2/s OCCM OCC mass flux
45- 54 E10.5 ubar P500 Bertrand & Forget (2016Natur.540...86B 2016Natur.540...86B)
atmospheric pressure for thermal inertia
TI=500 SI (J/s1/2/m2/K)
56- 65 E10.5 ubar P800 Bertrand & Forget (2016Natur.540...86B 2016Natur.540...86B)
atmospheric pressure for thermal inertia
TI=800 SI (J/s1/2/m2/K)
67- 76 E10.5 ubar P1200 Bertrand & Forget (2016Natur.540...86B 2016Natur.540...86B)
atmospheric pressure for thermal inertia
TI=1200 SI (J/s1/2/m2/K)
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Acknowledgements:
Andrew Poppe, poppe(at)berkeley.edu
(End) Patricia Vannier [CDS] 28-Aug-2018