The origin of stars and their planetary systems

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We are privileged to be living at a unique moment in human history. The age old questions of whether there are other worlds such as our own and whether they support life have been opened up to direct scientific investigation. Over the last 5 years, the Herschel space observatory has revealed where and possibly how stars are born. The Atacama Millimetre Array (ALMA) has just started to map the gaseous disks in which planets are born that accompany the birth of all stars. The Kepler space observatory identified thousands of new planetary candidates and revealed extensive populations of Jupters, as well as SuperEarths. We are poised as never before to address the question of how stars and their associated planetary systems form and evolve. In this research program we will develop new computational and theoretical avenues to address these fundamental and interrelated questions on three levels: how do stars form in the highly filamentary structures that dominate star forming clouds? How do planets form, migrate, and acquire their unique chemical compositions in the gasous disks that accompany stellar birth? And finally, how are the rocky Earth-like worlds equipped with the water and biomolecules such as amino acids that are fundamental to the development of life as we know it? Stars form in dense, cold, magnetized and turbulent gas gathered into discrete molecular clouds. Stellar masses range from a few hundredths a hundred times the mass of our Sun, and their mass distribution seems to be universal. Herschel revealed that molecular clouds are organized into a plethora of dense filaments extending from tens of parsecs (a parsec is typical length to our nearest star) down to sub parsec scales. Moreover, stars form in those regions within filaments where the mass per unit length exceeds a critical value above which gravitational forces take over leading to collapse. In this proposal, we will use new 3D computer codes and advanced theoretical methods to trace the gas motions and magnetic fields within these filaments, as well as compute the effect of feedback on the gas by radiation produced by the young stars, to determine how these processes yield a robust and universal stellar mass distribution. Planets form within disks of atomic and molecular gas and dust that orbit young stars. The gas disks live for 3-10 million years before they are finally dispersed by the radiation from young stars. During this time, young forming planets undergo strong gravitational interactions with the gas, leading to their rapid migration. We have developed a theoretical model wherein features in the disk such as density jumps or sudden changes in gas temperature act as dynamical planet traps. Here, planets move slowly inwards over millions of years (as observed) and accrete most of their composite iron, rock, ice, and gas. We will now be able to predict the composition of planets by connecting this picture of planets moving in their traps with a picture of the chemistry and composition of these disks. This work will provide modelers of planetary and atmospheric structure with critically needed information about the composition of planets. Finally, the development of life as we know it requires biomolecules such as amino acids that are the building blocks of proteins. Certain classes of meteorites are rich in amino acids and may have played a critical role in preparing our Earth for life. In this program, we will combine models for disk formation and chemistry with the synthesis of amino acids in meteorite parent bodies to predict the kinds of biomolecules that would be expected to shower onto young forming planets. This allows us to address how universal the conditions for life are in other planetary systems.