event
Thursday 19 Nov 2009: Observational studies of gas in protoplanetary disks
Dr. Andres Carmona Gonzalez - ISDC Astrophysics Data Centre, Geneva Observatory, Switzerland
Physics, 4th Floor interaction area 13:00-14:00
Circumstellar disks are essential in the process of star and planet formation. Early in the star's life they permit the inflow of material from the primordial cloud to the star and the outward transport of angular momentum. During the pre-main sequence, also known as the T Tauri phase, these reservoirs of dust and gas are the sites of planet formation. Although protoplanetary disks are composed of 99% gas and only 1% dust, our physical understanding of these disks has been based mostly on the study of dust emission. The dust dominates the opacity, therefore, it is much easier to observe. However, as the gas is the dominant mass component, to derive observational constraints of gas properties in the disk is fundamental for our understanding of disk physics, therefore, planet formation. Several fundamental questions about planet formation remain unanswered: How much material is available for forming planets?, How long is the disk life-time?, How does the disk dissipate?, What are the dynamics of disks? The answers to these questions will require direct observational constraints of the gas, especially from the region where planets are expected to form (R<10AU). The advent of high-resolution spectrographs in the IR opened the way to the observational study of the gas in the inner disk. In this talk I will review I discuss several observational diagnostics in the UV, optical, near-IR, mid-IR, and (sub)-mm wavelengths that have been employed to study the gas in the disks of young stellar objects. I will concentrate in diagnostics that probe the inner 20 AU of the disk, the region where planets are expected to form. I will discuss the potential and limitations of each gas tracer, what we have learned and present prospects for future research.
