The Monitor Daily (U.S.) – Globular clusters ‘steal’ gas from galaxies’ disks to nurture new stars as per the findings of a new study published in the Nature journal.
The dense, glittering globular clusters found in our galaxy as well as others are at least attention drawing. With the dense star population inhabiting them, the globular clusters are quite easy to spot. However, astronomers believed until recently that the myriad of stars populating each of these globular clusters are formed at the same time. As such, each of the glittering swarm of stars would be populated with almost twin stars.
The new study conducted by a joint team of astronomers from the Kavli Institute for Astronomy and Astrophysics at the Peking University, the Northwestern University, the National Astronomical Observatories of the Chinese Academy of Sciences and the Adler Planetarium took a closer look at stars in three globular clusters of the Magellanic Cloud.
With the help of the Hubble Space Telescope and data on the stars’ sizes, brightness and mass, the research team found that the globular clusters in question are in fact populated by newer generations of stars as well. It was unclear how the formation of new stars generations was possible.
It is conventionally assumed that globular clusters would shed gas gradually throughout their existence to spur the birth of new stars generations. Yet, this process is lengthy and implies the age difference between the stars in the global clusters is massive. The researchers found that globular clusters ‘steal’ gas from galaxies’ disks to nurture new stars.
Lead author Chengyuan Li stated that the study offers a new perspective on multiple star populations in globular clusters.
“Our study suggests the gaseous fuel for these new stellar populations has an origin that is external to the cluster rather than internal”.
Thus, globular clusters ‘steal’ gas from galaxies’ disk to nurture new stars. The material is external rather than internal as observations on the NGC 1783, NGC 1696 and NGC 411 globular clusters have shown. Part of the Large Magellanic Cloud and the Small Magellanic Cloud, the three glittering swarms of stars proved to be more complex than initially thought.
Contrary to the idea that stars in the globular clusters would have approximately the same age, the researchers brought forth another hypothesis. In the NGC 1783 cluster, several stars populations had different ages. Ranging from 1.4 billion years to 890 million years to 450 million years, their age reflects the idea that globular clusters ‘steal’ gas from galaxies’ disks to form new stars.
It is highly unlikely that these spherical swarms of stars retain sufficient gas and dust to birth multiple generations of stars. As stars explode into supernovae, they usually pump out the material from the confines of the globular clusters. If sufficient of them explode at the same time, a globular cluster may be left without any material for star formation at all.
Photo Credits: spacetelescope.org