Astronomers may have observed the birth of a black hole as a bright star in the Andromeda galaxy has mysteriously vanished. This celestial disappearance, believed to be the star’s collapse into a black hole, marks a significant moment in astronomical studies.
“It used to be one of the brightest stars in the Andromeda galaxy,” remarked Kishalay De, an astronomer affiliated with Columbia University and the Flatiron Institute. “Today, it is nowhere to be seen, even with the most sensitive telescopes.”
In a recent publication in the journal Science, De and his colleagues detailed their discovery, which emerged from an analysis of archival data spanning 15 years from NASA’s NEOWISE spacecraft. The team’s initial goal was to map the brightness changes of stars in infrared light, tracking millions over time. However, one star stood out as an anomaly.
The Disappearing Star
Around 2015, this star experienced a sudden increase in brightness for approximately a year, followed by a rapid decline in both infrared and optical light. By the time the team observed it again, it had vanished from optical view entirely.
“Scientists had known about this star for decades, and people used to be able to see it from their backyards using small telescopes,” noted De. “But now, we can’t even detect this source today with the Hubble Space Telescope.” In infrared light, it remains barely visible, even to the powerful James Webb Space Telescope.
These observations align with the theory that the star’s nuclear fuel had been exhausted, leading to its collapse into a black hole. The faint infrared glow that persists is likely powered by the remnants of the star continuing to fall into the black hole.
“We would predict that this continues to fade away into darkness,” De explained, though it could take decades to observe the complete process.
Understanding Stellar Death
Typically, massive stars end their life cycles in spectacular explosions known as supernovas, which are easily detectable due to their intense brightness. However, the theoretical possibility of a star quietly collapsing into a black hole without an explosion has been less understood and observed.
Suvi Gezari, an astronomer at the University of Maryland, commented on the study’s use of long-term infrared observations to uncover this otherwise obscured process. “This approach has opened up a new way to observe stellar deaths that are faint and difficult to detect,” she stated.
Only one other similar case of a disappearing star is known, but it was observed at a greater distance and with less detail. Christopher Kochanek, an astronomer from Ohio State University, who studied that event, noted, “It’s not quite a twin object, but it’s pretty similar.”
“This approach is the only game in town for seeing the formation of a black hole,” Kochanek emphasized.
Debate and Future Observations
Despite the compelling evidence, some astronomers remain skeptical. They propose alternative explanations, such as the possibility of merging stars whose light is obscured by a dust disc, as suggested by Kochanek. The debate is expected to continue as further telescope observations are conducted in the coming years.
“Fundamentally, the only way to clearly answer this either way is that one thing distinguishes the black hole case from any other scenario,” Kochanek concluded. “And that is that death is forever. Ultimately, it needs to fade to black.”
The implications of this discovery are profound, potentially offering new insights into the life cycles of stars and the processes leading to black hole formation. As astronomers continue to monitor the fading infrared glow, the scientific community eagerly awaits further developments that could confirm or challenge current theories.
