Shock-Generating Planetesimals Perturbed by a Giant Planet in a Gas Disk. (arXiv:1812.05250v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Nagasawa_M/0/1/0/all/0/1">M. Nagasawa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tanaka_K/0/1/0/all/0/1">K. K. Tanaka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tanaka_H/0/1/0/all/0/1">H. Tanaka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nomura_H/0/1/0/all/0/1">H. Nomura</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nakamoto_T/0/1/0/all/0/1">T. Nakamoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Miura_H/0/1/0/all/0/1">H. Miura</a>
We examined the excitations of planetesimals caused by the resonances of a
giant planet in a protoplanetary gas disk. The highly excited planetesimals
generate bow shocks, the mechanism of which results in chondrule formation,
crystallization of silicate dust, and evaporation of icy planetesimals. The
planetesimals beyond 2:1 resonance migrate owing to the gas drag and obtain the
maximum eccentricity around 3:1 resonance, which is located at approximately
half the planetary distance. The eccentricity depends on the parameters of the
planetesimals and the Jovian planet, such as size and location, and gas density
of the disk. The maximum relative velocity of a 100-km-sized planetesimal with
respect to the gas disk reaches up to ~12 km/s in the case of Jupiter owing to
secular resonance, which occurs because of the disk’s gravity. We find that if
a Jovian mass planet is located within 10 au, the planetesimals larger than 100
km gain sufficient velocity to cause the melting of chondrule precursors and
crystallization of the silicate. The maximum velocity is higher for large
planetesimals and eccentric planets. Planetesimals are trapped temporarily in
the resonances and continue to have high speed over >1 Myr after the formation
of a Jovian planet. This duration fits into the timescale of chondrule
formation suggested by the isotopic data. The evaporation of icy planetesimals
occurs when a Jovian planet is located within 15 au. This mechanism can be a
new indicator of planet formation in exosystems if some molecules ejected from
icy planetesimals are detected.
We examined the excitations of planetesimals caused by the resonances of a
giant planet in a protoplanetary gas disk. The highly excited planetesimals
generate bow shocks, the mechanism of which results in chondrule formation,
crystallization of silicate dust, and evaporation of icy planetesimals. The
planetesimals beyond 2:1 resonance migrate owing to the gas drag and obtain the
maximum eccentricity around 3:1 resonance, which is located at approximately
half the planetary distance. The eccentricity depends on the parameters of the
planetesimals and the Jovian planet, such as size and location, and gas density
of the disk. The maximum relative velocity of a 100-km-sized planetesimal with
respect to the gas disk reaches up to ~12 km/s in the case of Jupiter owing to
secular resonance, which occurs because of the disk’s gravity. We find that if
a Jovian mass planet is located within 10 au, the planetesimals larger than 100
km gain sufficient velocity to cause the melting of chondrule precursors and
crystallization of the silicate. The maximum velocity is higher for large
planetesimals and eccentric planets. Planetesimals are trapped temporarily in
the resonances and continue to have high speed over >1 Myr after the formation
of a Jovian planet. This duration fits into the timescale of chondrule
formation suggested by the isotopic data. The evaporation of icy planetesimals
occurs when a Jovian planet is located within 15 au. This mechanism can be a
new indicator of planet formation in exosystems if some molecules ejected from
icy planetesimals are detected.
http://arxiv.org/icons/sfx.gif
