| Project/Area Number |
05833006
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
惑星科学
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
NAKAZAWA Kiyoshi Tokyo Institute of Tech., Dep.of Sci., Professor., 理学部, 教授 (10025455)
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| Co-Investigator(Kenkyū-buntansha) |
IDA Shigeru Tokyo Institute of Tech., Dep.of Sci., associate Professor., 理学部, 助教授 (60211736)
OHTSUKI Keiji Yamagata Univ., Dep.of Sci., research associate, 理学部, 助手 (00250910)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1994: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1993: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | origin of the solar system / Kyoto model / Jorian planets / gas envelope / accretion of planetesimals |
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| Research Abstract |
To clarigy the formation processes of Jovian planets and the origin of their characters, we investigated (i) the static structure of the gas envelope covering a protoplanet and (ii) the collapse process of the unstable gas envelope and developed the simulation code describing (iii) the capture of the nebular gas by a protoplanet.
Our main results are summarized as follows.
(i) Static structure of the gas envolope covering a protoplanet
The structure of the gas envelope is mainly governed by the energy released in the envelope due to the accretion of planetesimals. Taking into account fragmention of incident planetesimals due to the dynamical pressure, we estimated the energy flux and obtained the static solution of the gas envelope. As a result, we showed that fragmentation of planetesimals fairly reduces the energy flux and the critical core mass and that the critical mass we obtained becomes 1/4 of the value obtained by the previous studies.
(ii) The collapse process of the unstable gas envelope
Next, we performed simulations of the collapse of the unstable gas envelope, taking into account the infall of the nebular gas. Futhermore, we analized the dynamical instability of the collapsing gas. Then we showed that the oscillational instability and the mass ejection suggested by Wuchterl (1993) do not occur. Our results support the formation process proposed in Kyoto model.
(iii) Capture of the nebular gas by a protoplanet
Using the results in (i) and (ii), we started the development of the new simulation code describing the capture of the nebular gas by a protoplanet. The previous study had a demerit that the way of the gas capture strongly depends on the algorism of the code. We are now developing the new code which can overcome the demerit.
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