Axions

I heard this story, Axions, on NPR during a StarDate program.
I am reading these articles, Axions and More Axions, on StarDate's website.
According to these articles, dark matter may consist of subatomic particles with almost zero mass called axions.
A great amount of dark matter, in the form of axions, was created a bit after the Big Bang.
And that axions may be created from X-rays, inside of stars.