Astronomers Capture Ultrasounds of Baby Stars

Humans use ultrasound to monitor the development of our babies, but it turns out that the same technology can be used to image baby stars.

Astronomers based out of the University of Leuven confirmed that echography is an effective method for distinguishing “infant” stars from those that are going through stellar puberty—meaning they are on the cusp of achieving nuclear fusion. The results of the study were published this week in the journal Science.

The team studied the acoustic vibrations of 34 stars in the Christmas Tree Cluster, a nebula located in the constellation Monoceras, the Unicorn. The stars ranged in size from one to four times the mass of the Sun, but all of them were under the age of 10 million, which is very young for a star.

The sound waves recorded by the team were generated by radiation pressure inside the stars. These stellar ultrasounds were collected with help from the Canadian MOST satellite, the European CoRoT satellite, and the European Southern Observatory in Chile.

"Our data shows that the youngest stars vibrate slower while the stars nearer to adulthood vibrate faster,” said first author Konstanze Zwintz in KU Leuven’s statement. “A star's mass has a major impact on its development: stars with a smaller mass evolve slower. Heavy stars grow faster and age more quickly.”

Accurately estimating the age of young stars has been a longstanding challenge for astronomers. But the data collected by the Leuven team will yield a new kind of stellar classification system, one that will pin down the age of young stars in the same way that spectral classification reveals their interior compositions.

"We now have a model that more precisely measures the age of young stars," said Zwintz. "And we are now also able to subdivide young stars according to their various life phases."

The fact that a star’s fetal development can be captured through ultrasound is just one more fun parallel between the lives of stars and our own. But as far as rebellious adolescences go, stars will always have us beat. Skipping school really doesn’t hold a candle to becoming an inconceivably massive fusion factory.