Turbulent gas may be responsible for Milky Way's low star production

A new study may help astronomers understand why the Milky Way has such low star production.
By Joseph Scalise | Mar 03, 2018
An international team of astronomers may have found why the Milky Way galaxy has such low star formation compared to other galaxies, according to newresearch published in the Monthly Notices of the Royal Astronomical Society.

In the middle of the Milky Way is an area known as the Central Molecular Zone (CMZ). That region -- which is present in galaxies throughout the universe -- is where new stars are formed. However, star formation in our galaxy's CMZ appears to be much less active than other systems.

To explain that, the team in the research used the Submillimeter Array (SMA) radio interferometer to look into the depths of the Milky Way. Such study enabled them to gather a sample of thirteen high-mass cores within the CMZ's "dust ridge" that may be young stars in the early stages of life. In addition, they also discovered two distinct that object that appear to be young, high-mass protostars.

Studying such bodies revealed that, despite known pressure differences, stars in the CMZ have roughly the same formation rate as ones in the galactic disk.

"All appear to be young (pre-UCHII), meaning that they are prime candidates for representing the initial conditions of high-mass stars and sub-clusters," the team noted in their research, according to Phys.org "We compare all of the detected cores with high-mass cores and clouds in the Galactic disc and find that they are broadly similar in terms of their masses and sizes, despite being subjected to external pressures that are several orders of magnitude greater."

The team also analyzed spectral lines of molecules formaldehyde and methyl cyanide as a way to measure both the temperature and kinetics of the gas in the CMZ. That showed the environment is highly turbulent, meaning it is likely responsible for inhibiting star formation in the region.

As a result, the study suggests thatthe rate of star formation in a CMZ is dependent on the nature of the gas environment, not the amount of gas and dust as previously believed.

This finding is important because understandingwhy the star formation in the Milky Way is different from other galaxies could help researchers answer many questions about our galaxy. They hope to continue their look into how stars are generated in the CMZ to better find out what mechanisms are behind the low production.

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