A strange ‘sneeze’ signal from a newborn star

(CN) – A newborn star deep within a cloud of gas and dust appears to be “sneezing,” sending out bursts of energy that may help explain how stars like the Sun form.

In one study published Thursday in The Astrophysical Journal Letters, scientists from Kyushu University and Kagawa University report that a young star surrounded by a dense disk of gas and dust ejected material in a way that created a massive, warm ring roughly 1,000 AU wide.

This is much larger than similar structures that have been seen before.

According to the researchers, these findings provide a closer look at the earliest stages of star formation, a process that is still difficult to observe directly because newborn stars are often hidden within thick clouds of gas.

“Fortunately, one of the most promising ways to get a clear picture of protostars is using the Atacama Large Millimeter/Submillimeter Array, or ALMA, in Chile,” said Masahiro Machida, a professor at Kyushu University who led the study, in a press release. “This radio telescope allows us to see the different materials that make up stellar nurseries.”

Using ALMA, the team studied a very young protostar in the Taurus Molecular Cloud, a nearby region where stars are actively forming. While stars like the Sun are about 4.6 billion years old, the object examined in the study is less than 100,000 years old.

Previous research by the same group identified smaller, spike-like structures in similar disks, about 10 AU in size. These features were linked to magnetic activity and were described by researchers as “sneezes” – bursts that release energy from the forming star.

The newly observed ring appears to be a much larger version of the same process.

“Our data showed that this ring is slightly warmer than its surroundings. We hypothesize that it is produced through a magnetic field that binds the protostellar disk,” said first author Kazuki Tokuda of Kagawa University in the press release. “The warm ring we discovered this time strengthens our hypothesis that young stars undergo dynamic redistribution of magnetic gas shortly after birth, generating shock waves that heat the surrounding gas.”

Machida said the term “sneeze” is meant to describe how the material is expelled.

“In simple terms, this is somewhat similar to a human sneeze, where the material is suddenly thrown out,” he said in an email. “These events appear to help the young star release the built-up magnetic energy.”

Magnetic fields are believed to play a critical role in star formation. Without a way to release excess magnetic energy, researchers say it would be difficult for stars to form under real conditions.

“Newborn stars have long been known to induce powerful bipolar outflows, often described as their ‘first scream,'” Machida said. “Our results suggest that, in addition, young stars may also undergo intermittent ‘sneeze’ events.

The discovery could also have implications for how planets form. The disk of gas and dust surrounding a young star is where planets eventually form, and changes in that environment can affect the development of planetary systems.

For now, researchers say more observations are needed to understand how common these large rings are and what exactly is going on inside them. The team plans to continue studying similar systems using ALMA and compare their findings with computer simulations.

“Not all young stars necessarily show this behavior, but similar characteristics are reported more often,” Machida said. “This suggests that such events may be relatively common, although further observations are needed to confirm this.”

The work adds to a growing body of research showing that star formation is not a quiet, steady process, but a dynamic one, shaped by bursts of energy and motion that are just beginning to come into focus.

“These results highlight that star formation is a highly dynamic process, involving not only steady accretion but also intermittent and energetic events,” said Machida. “Understanding these processes is essential to building a complete picture of how stars and planetary systems form.”