Electron temperature fluctuations in planetary nebulae

The temperature structure of dusty planetary nebulae

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 inferre...

The Electron Temperature in Ionized Nebulae

We discuss the role of the electron temperature in abundance determinations in ionized nebulae (planetary nebulae and giant H II regions). We show that, even when observations provide a direct estimate of T e, abundance determinations may sometimes be significantly in error for reasons other than hypothetical temperature fluctuations or uncertainties in ionization correction factors, and we sho...

Planetary Nebulae

Planetary nebulae (PNe) can be used to trace intermediate and old stellar populations in galaxies and the intracluster medium out to approximately 20 Mpc. PNe can be easily identified with narrow-band surveys, and their chemical abundances and radial velocities can be measured with multi-slit or multi-fiber spectrographs. We briefly review what has been accomplished to date, and include tables ...

Relation Between Source And Temperature Fluctuations In Photoionized Nebulae

Astronomy & Astrophysics The temperature structure of dusty planetary nebulae

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 inferre...