Astronomy Picture of the Day

    Discover the cosmos! Each day a different image or photograph of our
      fascinating universe is featured, along with a brief explanation
                    written by a professional astronomer.

                              2020 February 17

                  The Changing Surface of Fading Betelgeuse
                   Image Credit: ESO, M. Montargès et al.

   Explanation: Besides fading, is Betelgeuse changing its appearance?
   Yes. The famous red supergiant star in the familiar constellation of
   Orion is so large that telescopes on Earth can actually resolve its
   surface -- although just barely. The two featured images taken with the
   European Southern Observatory's Very Large Telescope show how the
   star's surface appeared during the beginning and end of last year. The
   earlier image shows Betelgeuse having a much more uniform brightness
   than the later one, while the lower half of Betelgeuse became
   significantly dimmer than the top. Now during the first five months of
   2019 amateur observations show Betelgeuse actually got slightly
   brighter, while in the last five months the star dimmed dramatically.
   Such variability is likely just normal behavior for this famously
   variable supergiant, but the recent dimming has rekindled discussion on
   how long it may be before Betelgeuse does go supernova. Since
   Betelgeuse is about 700 light years away, its eventual supernova --
   probably thousands of years in the future -- will likely be an amazing
   night-sky spectacle, but will not endanger life on Earth.

                      Tomorrow's picture: hunter stars
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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