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Cepheid Variable in M100

Top: An image of the grand design of spiral galaxy M100 obtained with NASA's Hubble Space Telescope resolves individual stars within the majestic spiral arms. (These stars typically appeared blurred together when viewed with ground-based telescopes.)
Credit: J. Trauger, JPL and NASA

Middle: This HST image of a region of M100 shows a class of pulsating star called a Cepheid Variable. Though rare, these stars are reliable distance indicators to galaxies. The top three frames were taken on May 9, 4, and 31 (l to r) and reveal that the star changes brightness.
Credit: Dr. Wendy L. Freedman, Observatories of the Carnegie Institution of Washington, and NASA

Bottom: This sequence of HST images chronicles the rhythmic changes in the Cepheid Variable shown above, which doubles in brightness over a period of 51.3 days.
Credit: Dr. Wendy L. Freedman, Observatories of the Carnegie Institution of Washington, and NASA

Courtesy Space Telescope Science Institute (STScI)

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Copyright, (c) 1995: Board of Trustees, University of Illinois


NCSA. Last modified 11/1/95.