The planetary exospheres are poorly known in their outer parts, since the neutral densities are low compared with the instruments detection capabilities. The exospheric models are thus often the main source of information at such high altitudes. We present a new way to take into account analytically the additional effect of the radiation pressure on planetary exospheres. In a series of papers, we present with an Hamiltonian approach the effect of the radiation pressure on dynamical trajectories, density profiles and escaping thermal flux. Our work is a generalization of the study by Bishop and Chamberlain (1989). In this first paper, we present the complete exact solutions of particles trajectories, which are not conics, under the influence of the solar radiation pressure. This problem was recently partly solved by Lantoine and Russell (2011) and completely by Biscani and Izzo (2014). We give here the full set of solutions, including solutions not previously derived, as well as simpler formulations for previously known cases and comparisons with recent works. The solutions given may also be applied to the classical Stark problem (Stark,1914): we thus provide here for the first time the complete set of solutions for this well-known effect in term of Jacobi elliptic functions.
Theory for planetary exospheres: III. Radiation pressure effect on the Circular Restricted Three Body Problem and its implication on planetary atmospheres
Conceptual framework for the application of deep neural networks to surface composition reconstruction from Mercury's exospheric data
INAF-IAPS（意大利国家天体物理研究所-行星科学研究所）；INAF-Osservatorio Astronomico di Trieste（意大利国家天体物理研究所-的里雅斯特天文台）；Augmented Intelligence Lab（增强智能实验室）；INAF-Osservatorio Astronomico di Padova（意大利国家天体物理研究所-帕多瓦天文台）；ASI - Italian Space Agency（意大利航天局）
Lyman $α$ observations of the transiting exoplanet HD 209458b enable the study of exoplanets exospheres exposed to stellar EUV fluxes, as well as the interacting stellar wind properties. In this study we present 3D hydrodynamical models for the stellar-planetary wind interaction including radiation pressure and charge exchange, together with photoionization, recombination and collisional ionization processes. Our models explore the contribution of the radiation pressure and charge exchange on the Ly$α$ absorption profile in a hydrodynamical framework, and for a single set of stellar wind param…
Sodium and potassium signatures in transiting exoplanets can be challenging to isolate from the stellar absorption lines. Here, these challenges are discussed in the framework of Solar System observations, and transits of Mercury in particular. Radiation pressure is important for alkali gas dynamics in close-orbiting exoplanets since the D lines are efficient at resonant scattering. When the star-planet velocity is >10km/s, eccentric exoplanets experience more than an order of magnitude higher radiation pressures, aiding atmospheric escape and producing a larger effective cross-section for abs…
Pre-conditioned Backward Monte Carlo solutions to radiative transport in planetary atmospheres. Fundamentals: Sampling of propagation directions in polarising media
The $N$-body problem is of historical significance because it was the first implementation of the Newtonian dynamical laws for the description of our Solar System. Motivated by this, the project's goal is to revisit this problem for small $N$ and find a solution for the trajectories of specific two-body and three-body configurations as well as the planetary orbits of our Solar System using a fourth order Runge-Kutta explicit iterative method. We find an adequate agreement in our results with planetary trajectories found online.
We present TES, a new n-body integration code for the accurate and rapid propagation of planetary systems in the presence of close encounters. TES builds upon the classic Encke method and integrates only the perturbations to Keplerian trajectories to reduce both the error and runtime of simulations. Variable step size is used throughout to enable close encounters to be precisely handled. A suite of numerical improvements are presented that together makes TES optimal in terms of energy error. Lower runtimes are found in all test problems considered when compared to direct integration using ias1…
Exploring the Outer Solar System with Solar Sailing Smallsats on Fast-Transit Trajectories and In-Flight Autonomous Assembly of Advanced Science Payloads
Effect of Different Stellar Galactic Environments on Planetary Discs I: The Solar Neighbourhood and the Birth Cloud of the Sun
我们计算了轨道，距离和时间的最接近太阳的恒星在太阳附近的已知位置，径向速度和自行。为此，我们使用了一个完整的银河系势能模型，它再现了银河系的局部z力、奥尔特常数、局部逃逸速度和旋转曲线。从我们的样本中，我们构造了初始条件，在观测的不确定性，与蒙特卡罗计划的12个最可疑的候选人，因为他们的小切向运动。我们发现，恒星Gliese 710将有最接近太阳的方法，在未来1.36百万年的距离约为0.34 pc。我们表明，一个代表太阳系的100 AU的测试粒子盘上的格利泽710的特性的飞越的影响是可以忽略不计的。然而，由于缺乏太阳附近大部分恒星的6D数据，可能存在更接近的方法。我们计算的参数，通过恒星，将导致明显的影响，太阳盘。关于太阳的诞生云，我们进行了实验，以大致再现观测到的轨道参数，如柯伊伯带的偏心率和倾角。现在我们知道，在银河系的环境中，例如恒星形成区，新生恒星的恒星密度足够高，可以在200天文单位内产生近距离相遇。此外，在这些银河系环境中，速度色散相对较低，通常约为1-3 km s-1。我们发现，在这些区域的典型情况下，速度色散约为1 km s-1，接近距离约为150 AU，我们近似地获得了当前太阳系中所见的偏心率和倾角。简单的分析计算恒星相遇对奥尔特云的影响。
