Rapid Stellar Spin May Explain How Stars Survive Supermassive Black Holes

Repeated Close Encounters

Astronomers have discovered stars that repeatedly skim past supermassive black holes without being completely destroyed. These stars survive each encounter while producing a new burst of light, a phenomenon that occurs as the star passes through the extreme gravitational field of the black hole.

In some of these systems, the resulting flares of light mysteriously fade in intensity with every subsequent return. While supermassive black holes—which possess masses millions to billions of times that of the sun—typically exert gravity capable of ripping matter apart, some stars are able to make repeated close passes.

The Role of Stellar Rotation

Researchers now believe that the key to this survival and the subsequent fading of light flares may be the initial state of the stars. Specifically, evidence suggests that the stars involved were already spinning extremely fast before they were captured by the black hole.

According to researchers, this rapid rotation could explain two primary mysteries: why the light flares fade over time and how the stars ended up in such extraordinarily tight orbits around the black hole.

Partial Tidal Disruption Events

These encounters are categorized as partial tidal disruption events. Unlike a full tidal disruption where a star is completely shredded, a partial event occurs when the star loses only a portion of its mass. If the star survives the initial encounter, it continues to orbit the black hole, losing additional material each time it passes close by.

This process allows scientists to observe the same star-black hole interaction repeatedly over months or years. The amount of material lost during these passages is determined by the star's internal composition; for example, low-mass stars are more easily torn apart than denser stars.

Scientific Implications

One specific case involving a star in a distant galaxy has been highlighted by Israeli scientists, who noted that the star's survival and return for a second encounter upends previous scientific consensus.