A team of researchers has made a groundbreaking discovery using the Center for High Angular Resolution Astronomy (CHARA Array) at Georgia State University. They were able to capture high-resolution images of two nova explosions in unprecedented detail, shedding new light on this rare astronomical phenomenon.
The researchers observed V1674 Herculis and V1405 Cassiopeiae, two novae that exploded in 2021. By using near-infrared interferometry, a technique that combines light from multiple telescopes, the team was able to create images of the early stages of these explosions with incredible clarity.
What's remarkable about these images is that they show an explosion that is not spherical, but rather two ejecta flows radiating almost perpendicular to each other. This suggests that the nova involved multiple ejecta interacting with each other in a complex and dynamic process.
Further analysis of the spectra from these observations revealed different velocity components in the hydrogen atoms, which are indicative of a powerful gamma-ray emitting shock wave forming as the collision of different velocity streams occurred.
The most striking result, however, came from the observation of V1405. Initially, it seemed like a single event, with only a bright central light source and few surrounding ejections. But further observations revealed that the diameter of this central region was incredibly small - approximately 0.99 milliarcseconds - corresponding to a radius of about 0.85 astronomical units.
What's more fascinating is that this suggests the outer layer of hydrogen-rich gas in V1405 was not fully ejected after over 50 days, indicating it remained enveloped by the binary system for an extended period.
These observations offer valuable insights into the complex nature of novae and their ability to serve as laboratories for studying shock waves and particle acceleration. Moreover, they provide a unique opportunity to directly observe what happens when two stars approach each other so closely, a phenomenon believed to occur in more than 10 percent of stars in the universe.
In short, these images mark a significant milestone in our understanding of novae, which were once thought to be simple explosions. Instead, they reveal a far richer and more complex phenomenon that continues to captivate scientists and astronomers.
The researchers observed V1674 Herculis and V1405 Cassiopeiae, two novae that exploded in 2021. By using near-infrared interferometry, a technique that combines light from multiple telescopes, the team was able to create images of the early stages of these explosions with incredible clarity.
What's remarkable about these images is that they show an explosion that is not spherical, but rather two ejecta flows radiating almost perpendicular to each other. This suggests that the nova involved multiple ejecta interacting with each other in a complex and dynamic process.
Further analysis of the spectra from these observations revealed different velocity components in the hydrogen atoms, which are indicative of a powerful gamma-ray emitting shock wave forming as the collision of different velocity streams occurred.
The most striking result, however, came from the observation of V1405. Initially, it seemed like a single event, with only a bright central light source and few surrounding ejections. But further observations revealed that the diameter of this central region was incredibly small - approximately 0.99 milliarcseconds - corresponding to a radius of about 0.85 astronomical units.
What's more fascinating is that this suggests the outer layer of hydrogen-rich gas in V1405 was not fully ejected after over 50 days, indicating it remained enveloped by the binary system for an extended period.
These observations offer valuable insights into the complex nature of novae and their ability to serve as laboratories for studying shock waves and particle acceleration. Moreover, they provide a unique opportunity to directly observe what happens when two stars approach each other so closely, a phenomenon believed to occur in more than 10 percent of stars in the universe.
In short, these images mark a significant milestone in our understanding of novae, which were once thought to be simple explosions. Instead, they reveal a far richer and more complex phenomenon that continues to captivate scientists and astronomers.