“Whippet” as envisioned by New Scientist picture desk
Credit: NASA/Muratato/Shutterstock/Adobe Stock
A mysterious burst of bright light in the night sky may indicate a black hole consuming an unusually sparse star.
In 2018, astronomers detected a new kind of cosmic explosion, designated AT2018cow, or “Cow.” This unique flash reached peak brightness in only a few days, significantly faster than typical supernovae.
Initially, the origins of these explosions were unclear. Since the discovery of Cow, several more similar events have been recorded, termed fast blue light transients (FBOTs), yet their origins remain enigmatic.
Recently, Liu Jialian and his research team at Tsinghua University in China propose that the latest cosmic flash, the brightest FBOT to date, results from an exotic star over 30 times the mass of the Sun shedding its outer hydrogen layer and becoming a meal for a black hole.
Named AT 2024wpp, or “Whippet,” this outburst was identified by the Zwicky Transitional Observatory in late 2024 and quickly outshone Cow by approximately tenfold. Liu’s team monitored the explosion using various telescopes, including the Swift X-ray Telescope, collecting data across different wavelengths.
The observed light spectrum indicates the explosion was over six times hotter than the Sun’s surface and expelled plasma at approximately one-fifth the speed of light. Approximately a month after the initial light burst, a previously unobserved X-ray outburst emerged, adding to the mystery of FBOTs.
Liu and his colleagues attribute these observations to a type of rare star known as a Wolf-Rayet star. This star features an exposed core devoid of gas. They argue that Whippet is a consequence of a Wolf-Rayet star being engulfed by a black hole approximately 15 solar masses.
The initial merger triggered the first light burst, while some remaining stellar material eventually spiraled towards the black hole, resulting in the second X-ray burst. As noted by Ashley Chrimes from the European Space Agency, “Of all the proposed explanations, this one is likely the least problematic.”
One of the most compelling elements supporting this theory is that the event appears to originate from young galaxies, where short-lived extreme stars like Wolf-Rayet stars are prevalent. Chrimes adds, “In this environment, such events would be expected, and we’re also observing this late-time bump, which could signal a significant post-merger response. This is indeed promising.”
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Source: www.newscientist.com
