Catch a Fading Star: Using Transient Dimming to Explore the Planet-Forming Zones of Young Stars

A population of low-mass stars, called ‘dipper stars,’ experience episodic dimming events that might not arise due to planetary transits. The team will use astrometric, imaging, and spectroscopic data to evaluate mechanisms other than disk or planetesimal occultation for stellar dimming. They will test the model of dust lofted by disk winds and exocomets on highly inclined and eccentric orbits.

They will also do multiple bandpass photometry to examine reddening of the starlight and put constraints on the dust size distribution. They will leverage prior experience with a supernova survey and use machine learning to develop an automated system to identify stellar dimming and eliminate false positives. The team will incorporate citizen scientists to expand the survey of dimming stars using amateur equipment.

They will use an existing program at University of Hawaii at Manoa to bring the work to high school students from under-represented groups, including Hawaiian natives. High schoolers will work on this project with UH scientists and Professors on six-month mentorships.

The purpose of this work is to examine the structure, dynamics, and composition of the inner regions of primordial disks. Inner disks exchange mass and angular momentum with the central star. These are the regions where planets form and grow.

This research will complement studies of outer disk regions probed by other means, e.g. ALMA. A connection between dips and winds would provide a new probe of photoevaporative and/or magnetohydrodynamic winds that could control evolution of mass and angular momentum in disks, which in turn are important factors in planet formation and evolution.

On the other hand, a link to planetesimals would provide a window on a critical stage of planet formation in these systems. Detailed photometric and spectroscopic investigations would allow studies of the composition of gases and solids in these disks that may also be incorporated in planets. This project will create a dipper “alerts” system that would usher studies of protoplanetary disk into the realm of multi-wavelength transient astronomy and serve as the basis for future time-series investigations using even more powerful observational resources.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.