Planetary Nebula Picture (APOD 15 Feb 2007)

[Perry Cooper]

What I see is not a star becoming a white dwarf but a solar system in the intermediate stage of formation. Energy from the formation is transforming into matter in the two opposing jets that then gravitationally twist around the rotating system and form dust in the star's ecliptic outside the region cleared by radiation pressure and planetary formation. How does one tell the difference between the collapse of the dust cloud during the final stages of a solar formation and a stars collapse into a white dwarf, late in its existence?

[aichip]

If energy were becoming matter, you would see equal amounts of antimatter also forming in the process. The most likely outcome would be electrons and positrons. These would then come together due to their opposite charges and annihilate each other, creating a gamma ray signature at two energy levels- 0.34 MeV and 0.51 MeV.

Since we do not see those two gamma signatures, we can conclude that antimatter is not present, and therefore has not been formed. Add to that the fact that we do not see any sort of condition that would induce the transformation of energy to matter and you can see why this idea is not considered.

One signature of white dwarf formation is its spectrum. Stars that have depleted their fuel have very little hydrogen left and do not create a hydrogen alpha line of any significance. Stars that are presently generating heat and light through fusion do have a hydrogen alpha line that can be detected easily.

If you pass the light of a star through a diffraction grating or a prism, you can analyze the spectrum and say without a doubt whether it has hydrogen or not, and if the hydrogen is absent (or nearly so), the star has used it up and is a white dwarf. Also, the percentage of helium is a strong indicator. More helium means more "ash" from thermonuclear fusion.

[NoelC]

Even more basic, I don't think fledgling solar systems glow like this.

-Noel