Stellar Evolution in Real Time

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Produced by the Space Telescope Science Institute’s Office of Public Outreach in collaboration with NASA’s Universe of Learning partners: Caltech/IPAC, Center for Astrophysics | Harvard & Smithsonian, and NASA Jet Propulsion Laboratory.
Video imagery:

  • Four-panel illustration of Betelgeuse ejection: NASA, ESA, STScI (E. Wheatley)
  • Four-panel illustration of Betelgeuse with graphic plotting changes in brightness: NASA, ESA, STScI (E. Wheatley)

Writer: Leah Ramsay
Designer: Leah Hustak, Joseph Olmsted
Science review: Dr. Quyen Hart
Education review: Jim Manning
Music from Music for Non-Profits


Photographs of space with planets, nebulae, stars, and galaxies move quickly past. Text, News From The Universe.
Photos of a stellar outburst with an arrow indicating direction to Earth and with one displaying the angle of the flare from Earth. Text, Stellar Evolution in Real time. August 17, 2022.
Astronomers are following up on the dramatic dimming of the red supergiant star Betelgeuse in 2019.
Observations by many telescopes, including NASA's Hubble Space Telescope, indicate the star ejected a substantial amount of its surface.
A darkened spot on the surface of the star in the View From Earth slide.
Text, Astronomers have never observed such a large Surface Mass Ejection.
A chart of brightness changes appears beneath the photo of the ejection. Text, When the ejected surface material moved away into space and cooled, it blocked the view of the star from Earth, making it appear dimmed for months. Betelgeuse has not returned to its regular pulsation rate, which astronomers have tracked for 200 years. Astronomers are keeping an eye on Betelgeuse to take advantage of the opportunity to observe a star's aging process as it happens.
The brightness chart includes two wavy lines. A dotted blue line labeled Predicted 400-day brightness has regular peaks and valleys. A red line labeled Measured changes in brightness has a gap, a sudden drop and rise, another gap, and then irregular peaks and valleys smaller than predicted.
Text, This news was brought to you in part by the Space Telescope Science Institute in Baltimore, MD.