Astronomers have watched a young sun-like star emit high-energy gamma radiation for the first time.
This observation represents the first evidence that this type of low-mass star, called a T. Tauri star surrounded by a disk of gas and dust, can emit gamma radiation. In short, this type of radiation is the most energetic form of light. In the future, these findings may have important implications for our understanding of stars and planetary systems during their formation years.
“This observational evidence is essential to understanding the origin of sources that previously remained unknown for more than a decade, and is undoubtedly a step forward in astronomy,” said Agostina Velokomo, discovery team leader and astronomer at the National University of La Plata. he said in a statement. “It is also important to understand the processes that occur during the early stages of star formation: if a T Tauri star produces gamma radiation, it will affect the gas conditions in the protoplanetary disk and, in turn, the evolution of planet formation.”
Astronomers recorded their observations of this intriguing star using the Fermi Space Telescope, which observes the universe in gamma rays. In other words, this telescope has the ability to collect high-energy radiation data that would otherwise be difficult to collect from Earth’s surface. Fermi has been monitoring the skies since its launch in 2008, but about 30% of the gamma rays it has seen have not yet been attributed to a source. And so, Velokomo and her team set out to try to identify some of these mysterious sources.
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Essentially, the research team found that many of the gamma rays appear to originate from regions where stars are actively forming. This is something that defies interpretation and therefore requires deeper investigation, with the team focusing on the star-forming region NGC 2071.
In particular, Velokomo and colleagues looked for T.Tauri stars in NGC 2071, which lies in the northern part of the Orion B molecular cloud, located about 1,350 light-years from Earth. T.Tauri stars are often found near star-forming regions, still trapped in the same gas and dust that created them. And because they’re surrounded by these mantles of gas, T. Tauri stars exhibit fluctuating levels of brightness — making them a type of variable star.
The team has identified three different sources of unknown gamma rays that appear to be coming from the direction of NGC 2071, where at least 58 T. Tauri stars are known to be forming. The researchers saw that there were no other objects in the area that could be sources of gamma-ray emissions.
The team believes that T. tauri stars can emit gamma rays intermittently during powerful flare events called “megaflares,” which occur when stored magnetic energy is released into a young star’s atmosphere in powerful electromagnetic bursts.
The concept is similar to the way the Sun triggers solar flares, except that they occur on a radically larger scale. Huge flares can span distances many times the radius of the stars that fired them in the first place, and are so powerful that if the Sun exploded like this one, life on Earth would be threatened.
However, despite this destructive potential, some scientists argue that huge flares in the early history of the solar system, when the sun was embedded in a disk of gas and dust, may have actually been beneficial to the birth of the planet by stimulating gas and triggering the formation of pebbles and other small rocky material. .
As such, the team’s findings could not only help explain previously unattributed gamma-ray detections, but could have implications for our understanding of the solar system – particularly during the period when our planet was created.
“The discovery of this phenomenon helps in understanding how not only the sun, but also our planet Earth formed and evolved,” Velokomo concluded.
The team’s research is published Aug. 23 in the journal Nature Monthly Notices of the Royal Astronomical Society.
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