Notre Dame astrophysicists identify missing fuel for Galactic star formation | News | Notre Dame News | University of Notre Dame Skip To Content Skip To Navigation Skip To Search University of Notre Dame Notre Dame News Experts ND in the News Subscribe About Us Home Contact Search Menu Home › News › Notre Dame astrophysicists identify missing fuel for Galactic star formation Notre Dame astrophysicists identify missing fuel for Galactic star formation Published: August 25, 2011 Author: Gene Stowe The Milky Way will have the fuel to continue forming stars, thanks to massive clouds of ionized gas raining down from its halo and intergalactic space. This is the conclusion of a new study by Nicolas Lehner and Christopher Howk, faculty in the Department of Physics at the University of Notre Dame. Their report, “A Reservoir of Ionized Gas in the Galactic Halo to Sustain Star Formation in the Milky Way,” was published in Science on Aug. 26. Using the Cosmic Origins Spectrograph, one of the newest instruments on the NASA/ESA Hubble Space Telescope, these researchers measured for the first time the distances to fast-moving clouds of ionized gas previously seen covering a large fraction of the sky. These fast-moving clouds reside in the distant reaches of the Milky Way and contain huge quantities of gas. The Milky Way would rapidly change its gas into stars if no supply of new matter were available to replenish the gas. Astronomers have hypothesized that the ionized fast-moving gas clouds could be this reservoir of gas, but it was not known if they were interacting with the Milky Way. “Our findings explain why the Milky Way can keep having star formation,” Lehner says. “Knowing the distances to these clouds tells us where the gaseous fuel is for forming stars over billions of years.” Gas clouds can be identified and studied because elements in the cloud absorb small amounts of the light from a star or other light source as it passes through a cloud on its way to the Earth. The characteristic “fingerprint” left in the spectrum allows astronomers to determine the properties of the gas. Earlier studies of these fast-moving ionized clouds used light from quasars, which are too far away to mark the clouds’ locations. To solve the problem, Lehner and Howk identified 27 stars around the Milky Way, whose distances were known, and used the Hubble to take line-of-sight readings of light coming from them. Results from the stellar sample showed the ionized clouds largely resided in the Milky Way’s halo. The authors concluded that these flows of ionized gas are within about one Galactic radius (40,000 light years) of Earth. The new Hubble observations revealed the presence of ionized gas in half the stellar sample, comparable to the fraction observed toward more distant quasars. The gas clouds are not uniformly distributed around the Galaxy, but rather collected in different areas. They cover only part of our Galactic sky, analogous to the partial coverage of the sky on a partly cloudy day on Earth. This research also confirmed models that predicted gas falling into the Milky Way slows as it approaches. Clouds closer to the Galaxy seem to have been decelerated and do not move as fast as those farther away, much like a meteorite slowing as it enters the Earth’s atmosphere. “We know now where is the missing fuel for Galactic star formation.” Lehner concludes. “We now have to learn how it got there.” For additional imgages, click here Contact: Nicolas Lehner, 574-631-5755, nlehner@nd.edu Posted In: Research Home Experts ND in the News Subscribe About Us Related October 05, 2022 Astrophysicists find evidence for the presence of the first stars October 04, 2022 NIH awards $4 million grant to psychologists researching suicide prevention September 29, 2022 Notre Dame, Ukrainian Catholic University launch three new research grants September 27, 2022 Notre Dame, Trinity College Dublin engineers join to advance novel treatment for cystic fibrosis September 22, 2022 Climate-prepared countries are losing ground, latest ND-GAIN index shows For the Media Contact Office of Public Affairs and Communications Notre Dame News 500 Grace Hall Notre Dame, IN 46556 USA Facebook Twitter Instagram YouTube Pinterest © 2022 University of Notre Dame Search Mobile App News Events Visit Accessibility Facebook Twitter Instagram YouTube LinkedIn