Indian Astronomers Discover Secrets of Open Cluster

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Breaking new ground, Indian astronomers from the Birla Institute of Technology and Science have harnessed the power of the AstroSat spacecraft to delve into the mysteries of the nearby open cluster NGC 6940. Their groundbreaking findings, revealed on December 21, provide unprecedented insights into the cluster’s properties and stellar populations.

Indian astronomers explore open cluster NGC 6940 with AstroSat

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Published on: August 31, 2021 Description: UOCS – III UVIT catalogue of open clusters with machine learning based membership using Gaia EDR3 a IEEE PROJECTS ...

UOCS – III UVIT catalogue of open clusters with machine learning based membership using Gaia EDR3 a

Hey there, science enthusiasts! Today, we have some exciting news from the world of astronomy. Indian astronomers from the Birla Institute of Technology and Science in Pilani have been using a spacecraft called AstroSat to investigate a nearby open cluster called NGC 6940. Their findings, which were published on December 21, provide us with more information about the properties and stellar populations of this cluster.

What are open clusters?

Before we dive into the details, let’s talk about open clusters. Open clusters are groups of stars that are formed from the same giant molecular cloud. They consist of a few tens to a few hundred stars that are loosely bound to each other by gravity. In our Milky Way galaxy alone, more than 1,000 open clusters have been identified. Studying these star groupings can help us better understand how our galaxy formed and evolved over time.

NGC 6940: A closer look

NGC 6940, also known as Melotte 232, is an open cluster that was discovered way back in 1784. It is located in the constellation Vulpecula, approximately 2,500 light years away from us. This cluster is estimated to be around 720 million years old and has a metallicity similar to our Sun.

Previous observations of NGC 6940 have uncovered some interesting findings. Apart from the normal single and binary stars, this cluster also contains some exotic stellar populations. These include blue straggler stars, blue lurkers, yellow straggler stars, and red clump stars. However, despite previous studies, these exotic stars have not been fully investigated yet.

AstroSat’s role in the study

To gather more information about the exotic stellar content of NGC 6940, astronomers Anju Panthi and Kaushar Vaidya used AstroSat’s Ultraviolet Imaging Telescope (UVIT). This telescope has the ability to detect exotic objects and their hot companions when combined with other multi-wavelength data. The researchers also utilized data from ESA’s Gaia satellite to identify cluster members.

What did they find?

After their observations, the astronomers identified a total of 492 members of NGC 6940. Out of these, 16 turned out to be exotic stars. They discovered 11 blue lurker star candidates, two yellow straggler stars, two red clump stars, and one blue straggler star. Interestingly, three of the blue lurker candidates are likely to have white dwarfs as hot companions, while the two yellow straggler stars have sdB stars as their likely hot companions. One of the red clump stars was found to have a white dwarf companion.

The study also revealed evidence of mass segregation within NGC 6940, suggesting that dynamic evolution has occurred within the cluster. The massive single stars showed the highest degree of segregation, followed by the equal-mass binary main sequence populations, and then the low-mass single stars. Additionally, the observations found the presence of an extended main-sequence turn-off (eMSTO) feature in NGC 6940. This suggests that the age spread of stars and the effect of stellar rotation and dust absorption may contribute to this phenomenon.

Conclusion

In conclusion, the study conducted by Indian astronomers using AstroSat has provided us with valuable insights into the properties and exotic populations of the open cluster NGC 6940. Their findings contribute to our understanding of how these star groupings form and evolve. It’s truly fascinating to see how modern technology and space exploration continue to expand our knowledge of the universe. Keep looking up at the stars, my friends!

SOURCE: Indian astronomers explore open cluster NGC 6940 with AstroSat

https://phys.org/news/2023-12-indian-astronomers-explore-cluster-ngc.html

FAQs

1. What are open clusters?

Open clusters are groups of stars that form from the same giant molecular cloud. They consist of a few tens to a few hundred stars that are loosely bound to each other by gravity. Studying these star groupings can help us better understand how our galaxy formed and evolved over time.

2. What is NGC 6940?

NGC 6940, also known as Melotte 232, is an open cluster located in the constellation Vulpecula, approximately 2,500 light years away from us. It is estimated to be around 720 million years old and has a metallicity similar to our Sun.

3. What is AstroSat and its role in the study?

AstroSat is a spacecraft used by Indian astronomers to investigate NGC 6940. In this study, astronomers used AstroSat’s Ultraviolet Imaging Telescope (UVIT) to gather more information about the exotic stellar content of the cluster. The UVIT has the ability to detect exotic objects and their hot companions when combined with other multi-wavelength data.

4. What did the astronomers find in NGC 6940?

After their observations, the astronomers identified a total of 492 members of NGC 6940, including 16 exotic stars. These exotic stars include blue straggler stars, blue lurkers, yellow straggler stars, and red clump stars. The study also revealed evidence of mass segregation within the cluster and the presence of an extended main-sequence turn-off (eMSTO) feature.

5. How do these findings contribute to our understanding of star groupings?

The findings from this study contribute to our understanding of how open clusters form and evolve. They provide valuable insights into the properties and exotic populations of NGC 6940, helping us understand the dynamic evolution and age spread of stars within the cluster.