Astronomers studying the fastest and most dramatic nova on record continue to find more puzzles than answers.
Novas are sudden, bright flashes of light in a two-star system created when a white dwarf, the core of a dying star that has run out of fuel, steals material from its companion star, causing the white dwarf to temporarily brighten. A nova known as V1674 Hercules found in a bizarre binary star system, composed of a White dwarf and a comminuted companion in the constellation Hercules – has been the subject of much interest ever since first erupted two years ago, on June 12, 2021. Astronomers were baffled by its light and energy, which rang like a bell, as well as its mysterious and intense winds that pumped stellar material in the surrounding space.
Now, a team of researchers has spotted strange radio emissions spewing from deep within the V1674 Hercules nova that are very different from the high-temperature emissions typically seen during such events. “Right now, we’re trying to determine whether the non-thermal energy is coming from gas clumps going into other gas clumps that produce shocks, or something else,” Montana Williams, a graduate student at New Mexico Tech who is leading the new research, said in a declaration.
Related: The fastest nova ever seen “rings” like a bell thanks to the power supply of the white dwarf
Williams revealed the strange emissions last week at a press conference at the 242nd meeting of the American Astronomical Society in Albuquerque and online. Those emissions could come from interactions between chunks of stellar material ejected during the explosion, which is pretty rare for”classical nova“like V1674 Hercules, said Williams.
“Classical novas have historically been thought of as simple explosions, mostly emitting thermal energy,” he added in the statement. “Instead, they seem to be a little more complicated.”
To study V1674 Hercules, Williams and his colleagues are using the Very Long Baseline Array, which is a network of ten antennas that spans the United States from Mauna Kea in Hawaii to Saint Croix in the Virgin Islands. Combining these observations with similar data from other telescopes also observing the nova, including the Karl G. Jansky Very wide range telescope facility in New Mexico and the Nuclear Spectroscopic Telescope Array (o NuSTAR), the team hopes to figure out what’s causing the mysterious radio emissions.
Researchers can measure how quickly a nova evolves by observing how long it takes for the explosion to fade two magnitudes from its maximum brightness. Extremely fast events take less than 10 days, moderate ones can take up to 80 days, and slow ones take 80 to 150 days. The V1674 Hercules nova (or V1674 Her), whose flash of light was so bright it could be seen with the naked eye, took just 1.1 days to dim by two magnitudes, or about a sixth of its original brightness.
“V1674 Her at 1.1 days is on the edge of an already extreme end, thus earning the title of fastest nova,” Williams said at a press conference last week.
A pair of newly released images from Williams and his team depict how drastic that pulsing change in brightness was between July 2, 2021 and July 6, 2021.
Unlike supernovae that completely destroy a star in violent explosions, classic novas like V1674 Hercules leave their host stars intact and are fully capable of putting on multiple shows, giving astronomers plenty of opportunities to study how the system works.
Broadly speaking, astronomers say studying the behavior and evolution of V1674 Hercules could also shed light on how galaxies evolve across eons, since the material that novas erupt into surrounding space is eventually recycled by nearby galaxies. to power the next generation of stars and planets.
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