Molecular Hydrogen Emission from the Disks of T Tauri Stars

Vanderbilt University, Nashville TN

Investigators

Abstract

AST 0307416 PI Weintraub This is a project to conduct a survey of the young T Tauri-type stars to ascertain whether evidence exists for the continued presence of their circumstellar disks at times beyond the epoch when the signatures of those disks as seen in submillimeter thermal emission and millimeter line emission have disappeared. Specifically, the researchers are carrying out an infrared survey of molecular hydrogen using very sensitive, high spectral resolution spectrometers primarily on the Gemini South telescope and the United Kingdom Infrared Telescope. Results from several years of preliminary work demonstrate the feasibility of detecting line emission from unshocked hydrogen around T Tauri stars. Previous results are consistent with the expected brightnesses of hydrogen emission and from the line shapes, it is shown definitively for one star and as likely for other stars, that the line emission is from gas in the middle layers of disks and from distances of 10 to 30 Astronomical Units (the earth-Sun distance) from the stars. A survey of hydrogen line emission from most of the T Tauri stars in several star forming regions will make an important contribution to developing a clearer understanding as to whether disks around Sun-like pre-main-sequence stars typically disperse prior to planet building or evolve toward planetesimals and planets within the first 10 million years. Broader Impact. All data will be made available to the public in the form of an on-line, searchable database of reduced, self-calibrated spectra. Also included on this project internet site will be web pages devoted to education and public outreach, including explanatory material concerning the role of spectroscopy in understanding the processes of star and planet formation. The Principle Investigator is actively engaged in bringing astronomy to teachers and students in the metropolitan Nashville area. He is a partner in a new program, "Exploring our Solar Neighborhood," which will bring astronomy content to teachers and students through teacher training workshops and student instruction. As part of these programs, which include a weeklong Summer Institute for 15 teachers and follow-up activities during the summer and school year with their students, the Principle Investigator will teach about the planets and about the processes by which planets form, thus bringing cutting edge knowledge and research from this program directly to teachers and potential future scientists. This regularly includes undergraduate students, especially those in a unique undergraduate major at Vanderbilt University called the Communication of Science and Technology, in the research activities of this project.