These tadpole‐like structures have been found in the Helix nebula, the closest planetary nebula to Earth—450 light‐years away. With the aid of Wide Field Planetary Camera 2 on the Hubble Space Telescope, C. Robert O’Dell and Kerry P. Handron of Rice University observed 313 of the well‐resolved structures, which they call cometary knots; their glowing heads and wispy tails resemble comets. O’Dell and Handron estimate that the entire nebula has 3500 of them.
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© 1996 American Institute of Physics.
1996
American Institute of Physics
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