Variable Young Stellar Objects Survey


Young stars undergo major changes during their evolution towards the main sequence. Additionally, the presence of a circumstellar accretion disk and its magnetic coupling to the central star leads to constant perturbations. It is therefore not a major surprise that virtually all young stars are variable, although amplitudes and timescales differ from one type to another, and depend as well on the evolutionary stage. It is becoming increasingly understood and appreciated that the rather static view of pre-main sequence evolution that has prevailed for many years is misleading, and that young stars cannot be understood without taking their continuous changes into account. Indeed, time-dependent phenomena may hold the key to an understanding of the way young stars grow and their circumstellar environments evolve, eventually leading to the formation of planetary systems.

T Tauri stars were originally identified through their irregular variability. This is now known as a fundamental property of young stars. However, after widefield photographic surveys went out of fashion, only limited work has been done on the photometric variability of young stars in newly formed associations.  In fact, current observations of e.g. important accretion events occur only through luck.  What is needed now is an ambitious observational program that recognizes young stars as the dynamic bodies they are and systematically monitors all of the nearest star forming regions, providing a synoptic view of early stellar evolution, and maintaining vigilance in order to identify whenever rare and potentially important events  occur in star forming regions along the Galactic plane.  Such an effort will dramatically affect our view of young stars and pre-main sequence evolution, probably even in ways we cannot foresee at the moment.

The VYSOS project aims at providing the continuous monitoring of all the major star forming regions that is required to understand the dynamic state of young stars.

The VYSOS Team:

Bo Reipurth (UH Manoa - Principal Investigator)

Ben Berkey (Technical Support)

Hsin-Fang Chiang (Postdoc - from Nov 1, 2011)

Chris Erickson (Engineer)

Martin Paegert (Postdoc - Vanderbilt)

Josh Walawender (Assist. Prof. UH Hilo - Project Manager)