New Delhi: Astronomers from the Centre for Astrophysics (CfA), Harvard and Smithsonian Institution have recently discovered a humongous cavity in space, which they believe could have been created by ancient supernovae that went off around 10 million years ago.
The astronomers found the giant void while studying 3D maps of nearby molecular clouds, which are areas in space where star formation occurs. These regions are also called stellar nurseries.
The study was recently published in the astrophysical journal, Letters.
What’s New In The Find?
The astronomers have discovered that the cavity is sphere-shaped, and has a diameter of 156 parsecs, which is around 500 light years. The mysterious cavity is located among the constellations Perseus and Taurus, according to a statement released by CfA.
Astronomers have found that Perseus and Taurus molecular clouds surround the cavity, suggesting the occurrence of star formation in that region.
The researchers have used 3D dust mapping techniques to understand how star formation occurs in molecular clouds, which are created from the diffuse interstellar medium (ISM). They have used the highest-resolution 3D dust map to date, in order to analyse the Perseus and Taurus molecular clouds.
Numerous stars are forming and already exist at the surface of the giant bubble, Shmuel Bialy, one of the researchers of the study, said in the CfA statement.
Bialy said they had two theories about how star formation may have occurred in the bubble. According to one theory, a supernova may have gone off at the core of the cavity and pushed gas outwards, resulting in the formation of the bubble, called the 'Perseus-Taurus Supershell'. The other theory says the bubble could have been created by a series of supernovae occurring over millions of years.
The astronomers have also found a large ring structure at the location of Taurus, known as Tau Ring.
Why The Findings Matter
While it is known that molecular clouds give birth to young stars, it has always been a mystery as to how these clouds are formed.
The discovery of the supershell suggests that the death of a star causes a supernova explosion, which eventually generates a series of events that result in the formation of new stars, the astronomers explain.
Perseus and Taurus molecular clouds formed together from the very same supernova shockwave, and were not independent structures in space, the study suggests.
The researchers explain in the study that previous stellar and supernova feedback events could have created a large expanding shell. This is because the diffuse interstellar medium condensed to form both the cavity and the surrounding molecular clouds, the researchers believe. Subsequently, star formation was triggered by the supernova feedback events.
How The Molecular Clouds Were Studied
Data was obtained from Gaia, which is a space-based observatory of the European Space Agency, and used to create 3D maps of the cavity and surrounding molecular clouds. A data visualisation software named Glue was used to create the 3D maps.
In a study published in The Astrophysical journal, the analysis of these stellar nurseries was described. A technique, known as dust reconstruction, developed by the Max Planck institute for Astrophysics in Germany, was used to develop the 3D maps.
This is the first time molecular clouds have been represented in 3D. Catherine Zucker, one of the researchers of the second study, explains that the 3D maps help determine the exact shape, size, depth or thickness of the molecular clouds and the distances between them, which couldn't be deciphered with the earlier maps that were 2D, according to a CfA statement.
Also, the location of the stellar nurseries and the void between them can now be discerned with just one percent uncertainty, she added.
She also explains that the maps allow real 3D views to compare different theories which determine how star formation occurs from the rearrangement of gas.
The Universe In Augmented Reality
The discovery of the void marks the first time astronomy visualisations are published in journals of the American Astronomical Society (AAS) in augmented reality (AR) — an interactive experience of the real world environment by enhancement of real-life objects with the addition of visual elements, sound, or sensory stimuli. The Perseus-Taurus Supershell and the surrounding molecular clouds can be visualised by using a smartphone to scan a QR code in the paper.
Alyssa Goodman, co-author of both studies, says future scientific articles must incorporate audio, video and enhanced visuals to make the research more interesting to scientists as well as the public. She added that 3D visualisations can provide a better understanding of the powerful effects of supernovae.