Properties of dust grains in planetary nebulae. I. The ionized region of NGC 6445

  title={Properties of dust grains in planetary nebulae. I. The ionized region of NGC 6445},
  author={Pam van Hoof and Griet Van de Steene and Douwe A. Beintema and P. G. Martin and Stuart Robert Pottasch and Ferland},
  journal={The Astrophysical Journal},
One of the factors influencing the spectral evolution of a planetary nebula is the fate of the dust grains that are emitting the infrared continuum. Several processes have been proposed that either destroy the grains or remove them from the ionized region. To test whether these processes are effective, we study new infrared spectra of the evolved nebula NGC 6445. These data show that the thermal emission from the grains is very cool and has a low flux compared to H beta. A model of the ionized… 
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