(CN) — A team of astronomers mapped out the structure and star-forming processes of a galaxy near our Milky Way and uncovered critical information about a unique star nursery in the cosmos, according to a study released Tuesday.
The stars we gaze upon in the universe are formed of clouds of gas and dust particles — also called molecular clouds — spinning within the structures of galaxies.
Within these stellar nurseries, tens of thousands of stars may develop in the lifetime of the molecular cloud.
To better understand star formation, scientists with the Physics at High Angular Resolution in Nearby Galaxies (PHANGS) project pointed a powerful telescope to the heavens.
Using the Atacama Large Millimeter/Submillimeter Array (ALMA) telescope project in Chile, scientists conducted a survey of 100,000 stellar nurseries across 90 galaxies in a section of the cosmos close to our own galaxy known as the nearby universe.
The study’s lead author Adam Leroy of Ohio State University said in a statement released with the findings that astronomers have generally believed stellar nurseries all behave in similar ways.
The scientists’ findings have shifted that paradigm.
"We used to think that all stellar nurseries across every galaxy must look more or less the same, but this survey has revealed that this is not the case, and stellar nurseries change from place to place," Leroy said. "This is the first time that we have ever taken millimeter-wave images of many nearby galaxies that have the same sharpness and quality as optical pictures. And while optical pictures show us light from stars, these groundbreaking new images show us the molecular clouds that form those stars."
The data revealed to the team of astronomers that while stellar nurseries share similar infrastructure and functions, their behavior varies dramatically, according to the study published Tuesday in the Astrophysical Journal Supplement.
Eva Schinnerer, astronomer at the Max Planck Institute for Astronomy and principal investigator for PHANGS, said in the statement the research team compared the variation to the differences one finds when going from town to town or travelling from country to country.
"To understand how stars form, we need to link the birth of a single star back to its place in the Universe. It's like linking a person to their home, neighborhood, city, and region. If a galaxy represents a city, then the neighborhood is the spiral arm, the house the star-forming unit, and nearby galaxies are neighboring cities in the region," Schinnerer said. "These observations have taught us that the ‘neighborhood’ has small but pronounced effects on where and how many stars are born."
A close analysis of the molecular clouds revealed differences in both the clouds’ properties and in how stars are formed in galaxy disks, stellar bars, spiral arms, and galaxy centers, according to the study.
Guillermo Blanc, astronomer at the Carnegie Institution for Science and a co-author on the paper, said the findings help astronomers understand how location and molecular cloud conditions impact the star-forming process.
"By mapping different types of galaxies and the diverse range of environments that exist within galaxies, we are tracing the whole range of conditions under which star-forming clouds of gas live in the present-day Universe. This allows us to measure the impact that many different variables have on the way star formation happens," Blanc said.
While ALMA has been used to image other galaxies, the team’s observation is the first glimpse at how stellar nurseries operate across a broad range of galaxies, Annie Hughes, astronomer at L'Institut de Recherche en Astrophysique et Planétologie, said in the statement.
"We found that the properties of star-forming clouds depend on where they are located: Clouds in the dense central regions of galaxies tend to be more massive, denser, and more turbulent than clouds that reside in the quiet outskirts of a galaxy,” Hughes said. “The lifecycle of clouds also depends on their environment. How fast a cloud forms stars and the process that ultimately destroys the cloud both seem to depend on where the cloud lives."
Study co-author Erik Rosolowsky of the University of Alberta said the findings offer data on a range of galaxies and new ways of understanding each star cluster.
"We are finally seeing the diversity of star-forming gas across many galaxies and are able to understand how they are changing over time,” Rosolowsky said. “It was impossible to make these detailed maps before ALMA. This new atlas contains 90 of the best maps ever made that reveal where the next generation of stars is going to form."
Researchers did not immediately respond to a request for further comment.
The team will present their findings this week at the 238th meeting of the American Astronomical Society.
Subscribe to Closing Arguments
Sign up for new weekly newsletter Closing Arguments to get the latest about ongoing trials, major litigation and hot cases and rulings in courthouses around the U.S. and the world.
