Computational Planet, Star and Galaxy Formation

计算天体物理学使天文学家的梦想，看到恒星和星系来生活和演变在他们眼前。 年轻恒星周围的气盘中可能有大量的气体。 通过计算机模拟，我们最近已经证明，这些圆盘在理想条件下会自发分裂，产生比木星更大的巨型气体行星。成对的年轻恒星几乎可以碰撞，并将圆盘撕裂成一串棕矮星。 这些圆盘和年轻的行星物体通过红外辐射失去热量的速度很慢，所以它们应该是膨胀的，我们现在打算在我们的模型中包括这一特性。 我们还将为整个年轻恒星群建模，以获得更真实和更激烈的行星形成环境！ 最近模拟的一个主要成功是在计算机上形成了令人信服的螺旋星系。 模拟的星系形成了数十亿年，消耗了气体和较小的星系，这被认为是相当安静的进化。 因此，它们包含了在宇宙年龄中形成的恒星薄盘，其形成方式与银河系中真实的恒星种群一致。 戏剧性的合并事件可以将这些安静的星系转变为宇宙中可见的所有星系类型，并将它们的一些气体和恒星驱动到中心贪婪的黑洞中。 为了更好地模拟这些星系，我们正在为气体及其冷却方式、黑洞、恒星如何形成以及恒星如何在高能超新星爆炸中死亡制定更详细的规定。

Computational astrophysics enables the astronomer's dream of seeing stars and galaxies come to life and evolve before their eyes.  Young stars can have substantial amounts of gas in disks around them.  With computer simulations we have recently demonstrated that these disks spontaneously fragment under ideal conditions to create giant gas planets larger than Jupiter. Pairs of young stars can nearly collide and shred the disks into a string of brown dwarfs.  These disks and young planetary objects are slow to lose their heat through infrared radiation and so they should be puffed up, a property we now intend to include in our models.  We will also model entire clusters of young stars for a much more realistic and violent planet forming environment!     A major success of recent simulations is the formation of convincing spiral galaxies on a computer.  The simulated galaxies form over billions of years, consuming gas and smaller galaxies in what is regarded as fairly quiet evolution.  As a result they contain thin disks of stars that formed over the age of the universe in a manner consistent with real stellar populations in the Milky Way.  Dramatic merger events can transform these quiet galaxies into the full range of galaxies types seen in the universe and also drive some of their gas and stars into voracious black holes at their centres.  To model these galaxies even better we are developing even more detailed prescriptions for the gas and how it cools, black holes, how stars form and how stars die in energetic supernova explosions.