The universe is over 13 billion years old, and for most of that time, it has been forming stars. But was the process different in the early universe? Researchers have long wondered about this, and a new study published in The Astrophysical Journal offers some answers.
A team led by Kazuki Tokuda studied the Small Magellanic Cloud (SMC), a dwarf galaxy near the Milky Way with lower metallicity than our own. They used the Atacama Large Millimeter-submillimeter Array’s (ALMA) power to examine 17 molecular clouds in the SMC, each with growing baby stars up to 20 times the mass of our Sun.
The researchers found that about 60% of these molecular clouds had a filamentary structure, while 40% were more “fluffy” and smooth. The temperature inside the filamentary clouds was higher than that of the fluffy ones, which suggested they started out as filaments but changed shape due to turbulence.
This change in shape can affect star formation. Clouds that hold onto their filamentary shapes are more likely to break apart along their length and form many lower-mass stars similar to our Sun. When these structures change to fluffy shapes, it becomes harder for such stars to form.
The study’s findings suggest that the environment plays a crucial role in maintaining a filamentary structure, which may be important for planetary system formation. Future research will address questions like how turbulence and magnetic fields shape filaments and affect star formation. The James Webb Space Telescope’s ability to probe physical properties of molecular gas will also help deepen our understanding of star formation in low-metallicity environments.
The discovery sheds new light on the early universe, which was mostly composed of hydrogen and helium. Heavier elements formed later in high-mass stars, and the study provides a rare glimpse into this period. The research’s lead author notes that “even today our understanding of star formation is still developing,” and studying the early universe is even more challenging due to its vast age and distance from us.
Source: https://www.universetoday.com/171024/fluffy-molecular-clouds-formed-stars-in-the-early-universe