New observations by the James Webb Space Telescope (JWST) could shed light on mysterious “little red dots” first spotted by the space observatory in 2022.
In the latest observations, scientists have discovered a new object they have dubbed “the Cliff”. The new discovery presents compelling evidence that the little red dots may in fact represent a completely new class of object – a “black hole star”.
These are essentially black holes feeding on their surrounding matter with such speed that a cocoon of surrounding gas starts to glow like a bright star.
The black hole star
In a new study, a team of astronomers focused on one particular little red dot that existed 1.8 billion years after the Big Bang. The object was originally identified in the Red Unknowns: Bright Infrared Extragalactic Survey (RUBIES), which is made up of James Webb observations.
The team, led by Anna de Graaff of the Max Planck Institute for Astronomy, published their findings this month in Astronomy & Astrophysics. They observed a dramatic, sudden jump in the brightness of the object. They named it “the Cliff” after this sharp rise in the spectrum.
According to the researchers, the sharp and sudden rise in brightness rules out existing theories regarding the little red dots. Scientists have suggested the red objects, observed in images capturing the early universe, could be massive galaxies or active galactic nuclei (AGN) – a galaxy powered by a massive black hole. However, these don’t exhibit such dramatic alterations in brightness.
Instead, the scientists believe they have observed a new class of object. “The extreme properties of The Cliff forced us to go back to the drawing board, and come up with entirely new models,” de Graaff explained in a press release.
The jump in brightness was sharp enough that it falls under the category of a Balmer break – a dramatic alteration in the light spectrum that originates from dense hydrogen gas at a specific temperature.
The researchers believe the object is a type of black hole never observed before. This black hole is surrounded by dense gas heated by the object’s accretion disk. This makes the black hole glow incredibly brightly, making it appear like a star. As such, the scientists dubbed the object a “black hole star.”
Explaining the emergence of supermassive black holes
It is worth noting that the black hole star hypothesis will require many more observations. Next, the team aims to use James Webb to study brighter little red dots, a report from LiveScience reveals. This will allow them to understand the structure of black hole stars better.
For now, the nature of the little red dots observed by James Webb remains a mystery. They have still not been assigned to any object class. However, if scientists accept the black hole star hypothesis, it may explain the evolution of early galaxies. Moreover, it could help explain the surprising emergence of supermassive black holes in the early universe.