Two Vast 'Peacock-Shaped' Cosmic Clouds Spotted by Astronomers in Nearby Galaxy

Astronomers have spotted a pair of vast peacock-shaped gaseous clouds in a satellite galaxy of the Milky Way.

The researchers identified the cosmic features in this neighboring galaxy—known as the Large Magellanic Cloud (LMC)—using telescopes at the Atacama Large Millimeter/submillimeter Array (ALMA) according to two papers published in The Astrophysical Journal.

Within these complex clouds, the astronomers identified several massive baby stars—a discovery which suggests that the LMC violently collided with another neighboring galaxy, the Small Magellanic Cloud (SMC), around 200 million years ago.

It is well established that stars are formed when interstellar clouds in space—formed mainly of hydrogen and helium—collapse under the weight of their own gravity. However, there is still some debate about how particularly large stars—those which are 10 times more massive than the sun or more—form due to the fact that compressing a sufficient amount of material into a relatively small space requires extremely strong forces.

One hypothesis proposes that these massive stars could be formed when galaxies interact with one another. According to this idea, the immense amount of gravitational forces involved in these interactions could stir up the clouds, potentially compressing materials into a sufficiently small area to form massive stars.

The ALMA data shows that the two peacock-shaped features are located about 150 light-years away from each other in a star-forming region of the LMC known as N159. Intriguingly, they look remarkably similar, indicating that they could have been produced in a similar manner.

peacock-shaped cosmic clouds
ALMA images of two molecular clouds: N159E-Papillon Nebula (left) and N159W South (right). Red and green show the distributions of molecular gas with different velocities. The blue region in N159E-Papillon Nebula shows the ionized hydrogen gas observed with the Hubble Space Telescope. The blue part in N159W South shows the emissions from dust particles obtained with ALMA. ALMA ESO/NAOJ/NRAO/Fukui et al./Tokuda et al./NASA-ESA Hubble Space Telescope

"It is unnatural that in two regions separated by 150 light-years, clouds with such similar shapes were formed and that the ages of the baby stars are similar," Kazuki Tokuda, one of the authors of the two studies from Osaka Prefecture University and the National Astronomical Observatory of Japan, said in a statement. "There must be a common cause of these features. Interaction between the LMC and SMC is a good candidate."

According to the astronomers, the latest findings could have important implications for our understanding of how massive stars form.

"For the first time, we uncovered a link between massive star formation and galaxy interactions in very sharp detail," Yasuo Fukui, lead author of one of the research papers, said in the statement. "This is an important step in understanding the formation process of massive star clusters in which galaxy interactions have a big impact."

The Small Magellanic Cloud is a dwarf galaxy located 200,000 light-years from Earth. Its larger cousin, the LMC—which contains around 30 billion stars—is located around 158,200 light-years away from us.