Possibility of Concentration of Non-volatile Species near the Surface of Comet 67P/Churyumov-Gerasimenko. (arXiv:1901.05170v3 [astro-ph.EP] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Suzuki_T/0/1/0/all/0/1">Taiki Suzuki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shinnaka_Y/0/1/0/all/0/1">Yoshiharu Shinnaka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Majumdar_L/0/1/0/all/0/1">Liton Majumdar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shibata_T/0/1/0/all/0/1">Takashi Shibata</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shibaike_Y/0/1/0/all/0/1">Yuhito Shibaike</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nomura_H/0/1/0/all/0/1">Hideko Nomura</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Minamoto_H/0/1/0/all/0/1">Harumi Minamoto</a>

The cometary materials are thought to be the reservoir of primitive materials
in the Solar System. The recent detection of glycine and CH$_3$NH$_2$ by the
ROSINA mass spectrometer in the coma of 67P/Churyumov-Gerasimenko suggests that
amino acids and their precursors may have been formed in an early evolutionary
phase of the Solar System. We investigate the evolution of cometary interior
considering the evaporation process of water followed by the concentration of
non-volatile species. We develop a Simplified Cometary Concentration Model
(SCCM) to simulate the evaporation and concentration processes on the cometary
surface.We use 67P/Churyumov-Gerasimenko as the benchmark of SCCM. We
investigate the depth of the layer where non-volatile species concentrate after
the numerous passages of perihelion after the formation of the Solar System. As
a result, the SCCM explains the observed production rates of water and
CH$_3$NH$_2$ at 99 comet years. SCCM results suggest that the non-volatile
species would concentrate beneath $sim$100~cm of comet surface within 10 comet
years. Our results also suggest that the non-volatile species would concentrate
several meters beneath the surface before it hit the early Earth. This specific
mass of non-volatile species may provide the unique chemical condition to the
early Earth.

The cometary materials are thought to be the reservoir of primitive materials
in the Solar System. The recent detection of glycine and CH$_3$NH$_2$ by the
ROSINA mass spectrometer in the coma of 67P/Churyumov-Gerasimenko suggests that
amino acids and their precursors may have been formed in an early evolutionary
phase of the Solar System. We investigate the evolution of cometary interior
considering the evaporation process of water followed by the concentration of
non-volatile species. We develop a Simplified Cometary Concentration Model
(SCCM) to simulate the evaporation and concentration processes on the cometary
surface.We use 67P/Churyumov-Gerasimenko as the benchmark of SCCM. We
investigate the depth of the layer where non-volatile species concentrate after
the numerous passages of perihelion after the formation of the Solar System. As
a result, the SCCM explains the observed production rates of water and
CH$_3$NH$_2$ at 99 comet years. SCCM results suggest that the non-volatile
species would concentrate beneath $sim$100~cm of comet surface within 10 comet
years. Our results also suggest that the non-volatile species would concentrate
several meters beneath the surface before it hit the early Earth. This specific
mass of non-volatile species may provide the unique chemical condition to the
early Earth.

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