Citizen scientists help unravel secrets of star formation

Analysis of thousands of photographs of the Andromeda galaxy taken by the Hubble Space Telescope could help explain how stars were born in our own galaxy.

J. Dalcanton, B.F. Williams, L.C. Johnson/University of Washington/NASA, ESA, and the PHAT team
Closeup of region of andromeda galaxy and star clusters captured by the Hubble Space Telescope.

Andromeda, our neighboring galaxy, is coming into focus, thanks to images captured by NASA’s Hubble space telescope and some help from citizen scientists.

Astronomers focused in on 2,753 young, blue star clusters in the Andromeda galaxy. Their analysis revealed that Andromeda and the Milky Way, our own galaxy, hold a similar percentage of newborn stars based on mass.

Andromeda may be 2.5 million light-years away, but it could provide a better understanding of our universe’s history. Already researchers have learned more about our universe from this data.

In the early universe, material for planet formation may not have been as readily available as previously thought. 

When massive stars explode in supernovae, the heavy elements needed to create planets is produced. And less mass means fewer supernovae.

Researchers in this study determined that there are 25 percent less of those brightest, heaviest stars in the clusters examined than previous studies suggested. 

Determining the percentage of stars of a particular mass within a cluster gave researchers the Initial Mass Function, or IMF. The IMF helps astronomers measure light from far away galaxies, as heavier stars burn brighter than those with less mass. That information opens doors to further research of Andromeda and opportunities to study the origin of stars and galaxies.

The analysis suggested that the thousands of clusters examined were remarkably uniform. Despite ranging in age from 4 to 24 million years old and varying greatly in mass, clusters around the galaxy contain a consistent distribution of various sized stars.

"It's hard to imagine that the IMF is so uniform across our neighboring galaxy given the complex physics of star formation," Daniel Weisz of the University of Washington in Seattle said in a news release. And yet the consistency appeared in clusters around the galaxy.

Before this study, astronomers had only determined the IMF for parts of the Milky Way. 

To complete this research, a team of astronomers and citizen scientists pored over nearly 8,000 images of Andromeda Galaxy, or M31, captured by Hubble. These citizen scientists worked as part of The Andromeda Project hosted by the Zooniverse organization.

Hubble reached age 25 this year. Over its lifetime, the space telescope brought new insights into space for people of all backgrounds.

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