行星形成在大轨道半径处的延迟和类木行星的质量和气体含量随着轨道半径递减

发布时间：2018-04-11 05:46

本文选题：类木行星 + 太阳星云　；参考：《吉林大学》2015年博士论文

【摘要】：在现代科学中,太阳系的形成模型是在星云假说的框架下建立的(Lissauer,1993)。虽然星云假说在一般意义上是成功的,但是细节性地描述太阳系历史的所有物理过程和解释所有的观测仍然是个挑战。任何理论必须解释的两个重要观测是行星的质量和组成。类地行星(水星,金星,地球,和火星)具有小质量而且主要由岩石物质组成,然而类木行星(木星,土星,天王星,和海王星)具有大质量而且除了包含固体物质外还包含大量氢氦气体。类地行星和类木行星之间的整体差别似乎已经有了解释。还有一个观测现象是类木行星的质量和气体含量除了天王星和海王星差不多之外,从木星开始大体上有一个向外递减的趋势(如图1.1)。木星,土星,天王星和海王星的质量分别为318,95,15,?17M。类木行星的模型建议它们的氢氦气体质量分别为307276-,7664-,0.55.0-,和?-7.45.0M.由上可知,太阳系的一个重要观测现象就是类木行星的质量和气体含量随着轨道半径从内向外递减(除了天王星和海王星的质量和气体含量差不多相等)。在以前的研究中,太阳星云被假定是先存在的并且太阳星云的形成过程没有被考虑。因此以前的研究都假定行星在太阳系中不同的轨道半径处是同时开始形成的。在本论文中,我们指出不同的轨道半径处的行星不是同时开始形成的且行星形成开始的时间点在大轨道半径处被延迟。我们建议这个延迟可能是导致类木行星的质量和气体含量随着轨道半径从内向外递减的一个因素。太阳星云是从内部区域开始形成的,因为它从之而来的分子云核是以从内到外的方式坍塌的。然后太阳星云因为粘滞的作用向外扩张。物质先到达小轨道半径处,然后再到达大轨道半径处。因此行星形成的时间起点在大轨道半径处被延迟。物质到达一个轨道半径处的时间越晚,留给此处行星用来获得质量和气体含量的时间越少。因此,这个延迟趋向于导致类木行星的质量和气体含量随着轨道半径从内向外递减。我们的星云模型表明物质到达木星,土星,天王星,和海王星的轨道半径的时间分别是,,和。我们在核吸积模型的框架下讨论了这个时间延迟对类木行星质量的影响。土星的形成相比较木星没有被延迟太长时间,所以土星和木星都到达了核吸积模型中气体快吸积阶段并且成为了气态巨行星。但是天王星和海王星的形成相比较木星就被延迟了很长时间,所以天王星和海王星的形成延迟可能就导致它们在气体星云耗散掉之前还没有到达气体快吸积阶段。土星虽然到达了气体快吸积阶段,但是此过程进行的不充分。所以土星的质量和气体含量都比木星少很多。我们的数值计算给出,木星在yr1040.06′时间点开始它的形成过程。在那个时间点后的很长时间段内(几个yr106),木星区域内都有大量的物质。有足够的时间和物质来让木星得到大质量和气体。它在类木行星中拥有最大的质量和氢氦气体。土星开始形成过程在yr1057.06′,比木星晚点但是没晚太多。木星和土星在太阳星云的寿命内都达到了气体快吸积阶段。它们在此阶段极大地增加了它们的质量。木星和土星都是气体巨行星。土星相对于木星的形成时间的延迟适合气体快吸积阶段的时间尺度可以比较的。所以土星进行气体快吸积阶段的时间尺度就比木星少。土星的质量和气体含量都远远低于木星的质量和气体含量。天王星和海王星分别在yr1050.16′和yr1029.66′时间点开始形成,比木星和土星晚的太多。天王星和海王星相对于木星的延迟分别为yr1010.16′和yr1090.56′。天王星和海王星形成的延迟太长,这可能是导致它们在气体星云耗散掉之前没有达到气体快吸积阶段的因素之一。所以它们是拥有比木星和土星小的质量的冰巨行星。总而言之,我们的研究表明行星形成在大半径处的延迟和延迟的程度是随着半径增加而增加的,而且表明延迟是由于太阳星云是从内部开始形成,然后在粘滞的作用下向外扩张造成的。我们显示在行星形成的核吸积模型框架下,类木行星的质量和气体含量的向外递减趋势可能是和此延迟有关的。我们的模型推断出气体快吸积阶段的时间尺度是yr105量级的,而且固体核形成时间尺度和气体慢吸积阶段时间尺度之和是yr106量级的。这些时间尺度和核吸积模型的时间尺度是一致的。在行星形成引力不稳模型框架下,这个时间延迟可能不会导致类木行星的质量和气体含量的向外递减趋势。
[Abstract]:In modern science, the formation of the solar system model is established in the framework of the nebular hypothesis (Lissauer, 1993). Although the nebular hypothesis is successful in the general sense, but the details of the description of the history of the solar system all the physical process and explain all of the observations is still a challenge. Two important observations of any theory to explain is the quality and composition of the planets. The terrestrial planets (mercury, Venus, earth, and Mars) with a small mass and is mainly composed of rock composition, but the Jovian planets (Jupiter, Saturn, Uranus, and Neptune) with high quality but also contains a solid material containing a large amount of hydrogen and helium gas. The difference between the terrestrial planets and planets seem to have been explained. There is an observed phenomenon is mass and gas content in addition to the Jovian planets Uranus and Neptune almost, from Jupiter in general There is an outward decreasing trend (Figure 1.1). Jupiter, Saturn, Uranus and Neptune mass were 318,95,15? 17M. the Jovian planets models suggest that their quality of hydrogen and helium gas are respectively 307276-, 7664-, 0.55.0-, and -7.45.0M.? Conclusionpsychotherapy mass and gas content is an important observation the phenomenon of the solar system's planets with orbital radius decreasing (from the inside to the outside, in addition to the quality and gas content of Uranus and Neptune almost equal). In previous studies, the solar nebula is assumed to be first and the formation of the solar nebula process have not been considered. So the previous studies assume that the orbit radius different planets in the solar system is at the beginning of the formation. In this paper, we point out that different planets orbit radius is not at the same time began to form and start time of planet formation in orbit Radius was delayed. We suggest that this delay may lead to quality and the gas content of the Jovian planets with an orbital radius from the inside to the outside factors decreasing. The solar nebula is formed from the inner region, because it comes from the molecular cloud core is from the inside to the outside party style collapse. Then the solar nebula because of viscous effect of outward expansion. The material first arrived at the small radius, and then reach orbit radius. So the time starting point of planet formation is delayed at large orbital radius. The material reaches a track radius at the late time, leave here for planetary mass and gas content time less. Therefore, this delay tends to lead to mass and gas content of Jovian planets with orbital radius from the inside to the outside. Our model shows that decreasing Nebula substances to reach Jupiter, Saturn, Uranus and Neptune. The radius of the orbit time are, and. We discussed the influence of time delay on the quality of the planets in the framework of nuclear accretion model. Saturn formation compared Jupiter has not been delayed too long time, so Saturn and Jupiter have reached the gas accretion model in nuclear fast accretion phase and become gaseous but the formation of giant planets Uranus and Neptune compared to Jupiter will be delayed for a long time, so the formation of Uranus and Neptune may cause them to delay has not reached the stage of fast gas accretion before nebular gas dissipation. Although Saturn arrived fast gas accretion phase, but this process is not so full. Mass and gas content are much less than Jupiter and Saturn. Our numerical calculation, Jupiter begins its forming process in yr1040.06 'time. At that point in time after the very Long time period (yr106), Jupiter within the region there are a lot of material. There is enough time and material to let Jupiter get big mass and gas. It has the largest mass of hydrogen and helium gas in the Jovian planets. Saturn began to form in the process of yr1057.06 ', but not later than Jupiter is too late. Jupiter and Saturn have reached a stage in the fast gas accretion in the solar nebula life at this stage. They greatly increased their quality. Jupiter and Saturn are gas giant planet Saturn and Jupiter. Compared with the delay time for fast gas accretion time scale can be compared. So Saturn gas fast the accretion phase time scale than Jupiter. Less mass and gas content of Saturn is far lower than the mass and gas content of Jupiter. Uranus and Neptune were started at yr1050.16 and yr1029.66' time points The formation of Jupiter and Saturn, than late too much. Jupiter, Uranus and Neptune to delay respectively yr1010.16 and yr1090.56 '. Uranus and Neptune form delay too long, this may be the cause of one of the factors they have not reached the stage of fast gas accretion before nebular gas dissipation. So they have than Jupiter and Saturn the quality of the ice giants. In short, our study shows that planets form in large radius delay and delay degree is increased with the increase of the radius, and that the delay is due to the solar nebula is formed from inside, and then the viscosity under the effect of outward expansion caused. We show the core accretion model framework the planets formed under the outward decreasing mass and gas content of Jovian planets may be delayed. And this is related to our model to infer the gas absorption Product stage time scale is yr105 magnitude, and the formation of solid state nuclear time scale and time scale and the slow accretion of gas phase is yr106 magnitude. The time scale and nuclear accretion model time scale is consistent. The planets formed gravitational instability model, the time delay may not lead to outward declining trend the quality and the gas content of the Jovian planets.

【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：P185

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