The temperature structure of dusty planetary nebulae..
Stasinska G, Szczerba R.
2001, A&A 379, 1024
Abstract:
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We have analyzed the effects of photoelectric heating by dust grains
in photoionization models of planetary nebulae.
We have shown that this process is
particularly important if planetary nebulae
contain a population of small grains.
The presence of such grains would solve a
number of problems that have found no satisfactory solution so far: i) the
thermal energy deficit in some objects inferred from tailored
photoionization modelling; ii) the large negative temperature gradients
inferred directly from spatially resolved observations and indirectly from
integrated spectra in some planetary nebulae;
iii) the fact that the temperatures derived from the Balmer jump are
smaller than those derived from [O III] 4363/5007;
iv) the fact that the observed intensities of [O I] 6300
are often larger than
predicted by photoionization models.
In presence of moderate density inhomogeneities,
such as inferred from high resolution images of planetary nebulae,
photoelectric heating would boost the temperature of the
tenuous component, which would then better confine the clumps.
The temperature structure of such
dusty and filamentary nebulae would solve the
long standing problem of temperature fluctuations posed by
Peimbert 1967.
PDF version of this paper is available:
aa1707.pdf
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