See a 3-D map of stellar nurseries based on data from the Gaia telescope

A new 3-D map provides the most detailed chart of nearby stellar nurseries yet, revealing the predicted glowing gas in and around all the star-forming regions within about 4,000 light-years of the sun.

“We live inside this sea of turbulent gas,” says astrophysicist Lewis McCallum of RWTH Aachen University in Germany. Knowing where that gas is, how it’s moving and how it’s being heated and cooled is crucial for answering big questions in astronomy, such as how stars form.

McCallum and his colleagues based their work on a 3-D map of interstellar dust created using data from the Gaia spacecraft. Because dustier regions correspond to areas with more hydrogen gas — the stuff that fills most of the space between stars — the researchers converted the dust map into one showing hydrogen.

They then added the influence of 87 stars known as O type, a rare class of enormous, extremely hot suns. “Stellar nurseries are the only places we really see these giant stars, because they are so short-lived,” says McCallum, who did this work while at the University of St. Andrews in Scotland. Moreover, “the energy of the light that’s coming out of these stars is so high that it’s able to rip electrons off of atoms, all mostly hydrogen.”

When an electron returns to a hydrogen atom, it emits a specific wavelength of light. Computer simulations, accounting for the brightness and temperature of each of the ultrahot stars, mapped where the hydrogen gas should glow. The new map, reported in the June Monthly Notices of the Royal Astronomical Society: Letters, overlaps well with an older, less detailed map of observed gleaming hydrogen just beyond the solar system.

“What we have then is this potentially quite accurate idea of how far these [particles of light from the stars] are getting, where they’re depositing their energy,” McCallum says. “Then we can start to understand a little bit more about how all this gas formed.”