The First Census of Accreting Proto-Planets inside the Gaps of Transitional Dust Disks

University Of Arizona, Tucson AZ

Investigators

Abstract

Thousands of gas-rich exoplanets are now known. None of these are true protoplanets that are rapidly adding gas from the areas surrounding them as they form. The investigators have developed a method of detecting the addition of hydrogen gas into a forming planet. This method can be used to search the empty regions or gaps in dust disks located around stars where planets are expected to be forming. The team has a unique instrumental system that they designed, tested, and now use with a 6.5-m telescope in Chile. They have made the first detection of hydrogen gas being drawn into a forming planet about twice the size of Jupiter in the gap of a dust disk. This project centers on applying their technique to search for protoplanets in 25 disks that are nearby, young, and have known gaps. They plan to learn how gas giant planets form, grow, and affect the dust disks in which they are forming. This project serves the national interest by increasing our understanding of how planets form. The investigators will train and include undergraduate and graduate students, and post-doctoral scientists, in this research project. The principal investigator will give public lectures on results from the protoplanet survey at Tucson area elementary and middle schools, as well as 10 Tucson area retirement communities. While thousands of gas-rich exoplanets are now known, none are true protoplanets that are rapidly accreting gas. The principal investigator's MagAO system on the 6.5-m Magellan Telescope in Chile is the only adaptive optics system that has published <0.03 arcsec resolution images at the strongest visible gas accretion emission line (H-alpha). Transitional disks are disks that have dust-poor gaps. One popular hypothesis is that these gaps could be cleared by multiple (2-3) massive accreting planets in the gap. This team has made the first definite detection of an approximately 2x Jupiter mass accreting protoplanet at H-alpha in the gap of the LkCa 15 transitional disk. The team will expand their observational studies by leveraging all the lessons they have learned about direct imaging of protoplanets to make the first census of nearby accreting protoplanets. They anticipate understanding where low mass gas giant planets form, grow, and how they affect their host disks/gaps. The team will utilize MagAO's unique ability to take simultaneous H-alpha (wavelength = 656nm), continuum (642nm), and Ks (2147nm) images to carry out a survey for protoplanets with the new simultaneous differential imaging optics, named the GAPplanetS+. They will survey all 25 nearest (~150 pc), youngest (~1 Myr), brightest (R<12 mag) large gap (>130mas) transitional disks for the first census of protoplanets. The investigators will train and include undergraduate and graduate students, and post-doctoral scientists, in this research project. The principal investigator will give public lectures on results from the GAPplanetS+ survey at Tucson area elementary and middle schools, as well as 10 Tucson area retirement communities.