Cliff collapse on Comet 67P/Churyumov-Gerasimenko — II. Imhotep and Hathor
Bj"orn J. R. Davidsson
arXiv:2404.13030v1 Announce Type: new
Abstract: Cliff collapses on Comet 67P/Churyumov-Gerasimenko expose relatively pristine nucleus matter and offer rare opportunities to characterise ice-rich comet material. Here, Microwave Instrument for emph{Rosetta} Orbiter (MIRO) observations of two collapsed or crumbling cliffs in the Imhotep and Hathor regions have been assembled. The empirical diurnal antenna temperature curves are analysed with thermophysical and radiative transfer models in order to place constraints on the physical properties and degrees of stratification in the near-surface material. The Imhotep site consists of an exposed dust/water-ice mixture with thermal inertia 100-$160,mathrm{J,m^{-2},K^{-1},s^{-1/2}}$, having sublimating $mathrm{CO_2}$ ice located $11pm 4,mathrm{cm}$ below the surface. Its estimated age is consistent with an outburst observed on 2014 April 27-30. The Hathor site has a $0.8pm 0.2,mathrm{cm}$ dust mantle, a thermal inertia of $40pm 20,mathrm{J,m^{-2},K^{-1},s^{-1/2}}$, no $mathrm{CO_2}$ ice to within $1.0,mathrm{m}$ depth, and a mantle bulk density of $340pm 80,mathrm{kg,m^{-3}}$ that is higher than the theoretically expected $180pm 10,mathrm{kg,m^{-3}}$, suggesting that compression has taken place.arXiv:2404.13030v1 Announce Type: new
Abstract: Cliff collapses on Comet 67P/Churyumov-Gerasimenko expose relatively pristine nucleus matter and offer rare opportunities to characterise ice-rich comet material. Here, Microwave Instrument for emph{Rosetta} Orbiter (MIRO) observations of two collapsed or crumbling cliffs in the Imhotep and Hathor regions have been assembled. The empirical diurnal antenna temperature curves are analysed with thermophysical and radiative transfer models in order to place constraints on the physical properties and degrees of stratification in the near-surface material. The Imhotep site consists of an exposed dust/water-ice mixture with thermal inertia 100-$160,mathrm{J,m^{-2},K^{-1},s^{-1/2}}$, having sublimating $mathrm{CO_2}$ ice located $11pm 4,mathrm{cm}$ below the surface. Its estimated age is consistent with an outburst observed on 2014 April 27-30. The Hathor site has a $0.8pm 0.2,mathrm{cm}$ dust mantle, a thermal inertia of $40pm 20,mathrm{J,m^{-2},K^{-1},s^{-1/2}}$, no $mathrm{CO_2}$ ice to within $1.0,mathrm{m}$ depth, and a mantle bulk density of $340pm 80,mathrm{kg,m^{-3}}$ that is higher than the theoretically expected $180pm 10,mathrm{kg,m^{-3}}$, suggesting that compression has taken place.

Comments are closed, but trackbacks and pingbacks are open.