Recent observations have shed new light on the star formation history of the solar neighborhood. One of the most significant is the recognition of several associations of very young and nearby stars. These observations suggest there may be previously unrecognized pre-main sequence stars near Earth, either in a distributed population or in loose associations that are no longer associated with molecular gas from which they formed. If they can be found, such stars would be very useful in constraining both the star formation history in the solar neighborhood and models of the evolution of protoplanetary disks. The PI here is continuing a survey for nearby young stars that are not members of known star forming regions. This research has already yielded discovery of dozens of previously unknown young stars, some of which are quite near Earth. The aims of this survey are: (1) to search for young stars in a way that is not biased toward or against stars with circumstellar disks; and (2) to use the stars discovered as laboratories to study disk evolution at ages when planet formation around them should be occurring.
Broader impacts. The PI involves a significant number of undergraduate student researchers in all aspects of the scientific process, including proposal writing, observations at the telescope, archival data research, data reduction and analysis, and presentation of results at meetings and in the literature. The high quality spectroscopic data obtained during this observational program will be made available to the astronomical community for other investigations of these stars' properties. Finally, understanding how planets form (and possibly discovering new planets) is of great popular interest. The PI draws on this interest and uses results from this research program to motivate his undergraduate students at all levels to learn more fundamental science and to become informed citizens. The PI also presents regular popular-level talks about this research to spread the results of NSF-supported science to a larger audience.
