Most people are familiar with supernovas, the spectacular stellar explosions that occur at the end of a massive star’s life and often result in a black hole or neutron weird star. On the other hand, novas are much less well known to the general public, even though they occur far more frequently than supernovas, perhaps because they usually are not nearly as dramatic.
A nova is a sudden, short-lived, dramatic brightening of a star. Typically, the star slowly fades to its original brightness over several weeks or many months. Although the specific causes of a nova can vary with the circumstances, they always involve white dwarf stars in close binary systems two stars that orbit around each other bound by gravity. Now, astronomers are buzzing after observing the fastest nova ever recorded. The unusual event drew scientists’ attention to an even more unusual star. As they study it, they may find answers to not only the nova’s many baffling traits, but to larger questions about the chemistry of our solar system, the death of stars and the evolution of the universe.
The research team, led by Arizona State University Regents Professor Sumner Starrfield, Professor Charles Woodward from the University of Minnesota and Research Scientist Mark Wagner from The Ohio State University, co-authored a report published today (June 14, 2022) in the Research Notes of the American Astronomical Society. A nova is a sudden explosion of bright light from a two-star system. Every nova is created by a white dwarf the very dense leftover core of a star and a nearby companion weird star. Over time, the white dwarf draws matter from its companion, which falls onto the white dwarf. The white dwarf heats this material, causing an uncontrolled reaction that releases a burst of energy. The explosion shoots the matter away at high speeds, which we observe as visible light. The bright nova usually fades over a couple of weeks or longer. On June 12, 2021, the nova V1674 Hercules burst so bright that it was visible to the naked eye — but in just over one day, it was faint once more. It was like someone flicked a flashlight on and off.
Nova events at this level of speed are rare, making this nova a precious study subject. “It was only about one day, and the previous fastest nova was one we studied back in 1991, V838 Herculis, which declined in about two or three days,” says Starrfield, an astrophysicist in ASU’s School of Earth and Space Exploration. As the astronomy world watched V1674 Hercules, other researchers found that its speed wasn’t its only unusual trait. The light and energy it sends out is also pulsing like the sound of a reverberating bell.
Additionally, novae can tell us more about how weird star in binary systems evolve to their death, a process that is not well understood. They also act as living laboratories where scientists can see nuclear physics in action and test theoretical concepts.The nova took the astronomy world by surprise. It wasn’t on scientists’ radar until an amateur astronomer from Japan, Seidji Ueda, discovered and reported it. Citizen scientists play an increasingly important role in the field of astronomy, as does modern technology. Even though it is now too faint for other types of telescopes to see, the team is still able to monitor the nova thanks to the Large Binocular Telescope’s wide aperture and its observatory’s other equipment, including its pair of multi-object double spectrographs and exceptional PEPSI high resolution spectrograph. They plan to investigate the cause of the outburst and the processes that led to it, the reason for its record-breaking decline, the forces behind the observed wind, and the cause of its pulsing brightness.
Source: This news is originally published by scitechdaily