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How do stars and planets form and evolve?

Everything you’ve ever seen or experienced on Earth was once a nebulous collection of floating gas and dust. Science is starting to understand how those particles came to take the forms you recognize today, teaching us about Earth’s primordial history and guiding our search for extraterrestrial life.

Our Work

Asteroids are time capsules, remnants from the era of planet formation. The same chemical makeup of the protoplanetary disk has been immaculately preserved in an asteroid and offers a trove of information about the early Solar System. Center for Astrophysics | Harvard & Smithsonian scientists are working on the Origins, Spectral Interpretation, Resource Identification, Security, Regolith, Explorer (OSIRIS-REx), which is currently on its way to the asteroid Bennu. Once in orbit around the asteroid, OSIRIS-REx will spend several months analyzing the surface before collecting a surface sample and returning to Earth.

Protostars are so embedded in their cloud of gas and dust that traditional optical telescopes cannot find them. By observing at lower energy wavelengths, the Submillimeter Array (SMA) is able to peer through the clouds and explore these young stars. Astronomers are using the SMA to study dense cores before the onset of star formation and to probe the disks and dynamics of protostars.

Likewise, the X-rays that young stars give off can also penetrate the gas and dust. Young stars shine brighter in X-rays than older stars which can be used to identify the young stars in a sample. CfA scientists use NASA’s Chandra X-ray Observatory, along with other other observatories, to study the survival time of protoplanetary disks and how the stars affect planets in their earliest stages of formation.

Chandra is also essential to study the death of stars. Supernova remnants and the elements they produce generate extremely high temperatures — millions of degrees — even thousands of years after the explosion. Chandra is able to gather detailed information about the elements that supernovae spread throughout the Universe. Many of the elements needed for life were created in a supernova.

The CfA’s Institute for Theory and Computation studies the dynamics of star birth and death by running computer simulations. They find a complex interplay between gravity pulling material toward the young star and radiation pressure pushing it out. Gas and dust form a circumstellar disk that continually accretes onto the star. But as more material falls onto the star, it heats up and ionizes the surrounding gas. This intense heat and light pushes material outwards, limiting the accretion from the disk. Simulations reveal the star channels this energy in the form of outflows near the poles, allowing material to continually feed the star via the disk. This shows how some of the most massive stars in the Universe form.

Though we can’t hit rewind on our own Sun and Earth to see how they originated, we can test observations and theoretical developments against the results we see in our own Solar System. Our scientists probe the task from all sides—from observation of the dense cloud cores and circumstellar disks of matter that serve as the incubators of star and planet formation, to the development of fine-tuned computer modeling of supernova.