[aerohead]

I went to the NASA website, under a search for 'dark star.'
They showed a cold, interstellar gas nursery, imaged from the Hubble Space Telescope, which is giving birth to new stars.
Anything above 2-degrees Kelvin has a radio signature which can be 'observed' with a radio telescope.
They are 'dark', optically, but that's why we use radio-astronomy.
These dark, cold, nurseries aren't technically 'stars' themselves, they're just giving birth to them, once they 'ignite.'