FAST Measures Hydrogen Absorption in Planetary Nebula
Scientists detected neutral atomic hydrogen absorption in planetary nebula IC 4997, which is a fancy way of saying there is cold hydrogen gas.
Our Sun is a main-sequence star. This means that sometime in the far distant future, about five billion years down the road, our star will puff up into a red giant. Even further down the road, it may blow off enough material to become a white dwarf. In the process, expanding shells of gas and dust might be ejected and form a planetary nebula, which would be gorgeous to see, if any of us were still around in our robot bodies to do so.
In the meantime, we have other planetary nebulae we can observe that can help us understand the chemical evolution of stars and even galaxies. A new paper on arxiv.org examines one such planetary nebula — IC 4997 — using the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in China. This particular planetary nebula is about 8,000 light-years away in the constellation of Sagitta and has a relatively high surface brightness and bright central star. Additionally, IC 4997 is rapidly evolving, which makes it a great observational target.
Analyzing the radio data, scientists detected neutral atomic hydrogen absorption in IC 4997…
