What is the sequence of stars to planets to life?|
Stellar evolution is one of the most successful theories of twentieth century astrophysics. Despite this success, we do not have good pictures for the structure and evolution of the lowest mass stars and brown dwarfs, how the surfaces of the Sun and stars influence their local environments, and how stars evolve from red giants to planetary nebulae and white dwarfs. These processes have broad implications throughout the Universe, from the evolution of life on Earth and the cycle of stellar birth and death, to the structure and evolution of galaxies.
Star formation is central to the evolution of galaxies. Interstellar material collapses to make new stars. Stars cycle new elements, molecular gas, and dust back into the galaxy. In the last 20 years, scientists have constructed a picture of star formation in our galaxy. Now, we seek to resolve major uncertainties in this picture and to understand the complex processes that lead from clouds of gas and dust to stars, planets, and the emergence of life.