Astronomers Find 3 ‘Infant Planets,’ Roughly The Mass Of Jupiter, Orbiting A Nearby Star In The Milky Way

A pair of new studies published in Astrophysical Journal Letters hails the discovery of a young planetary system some 330 light-years away from Earth, Science Daily reports.

The system consists of three newly formed planets gravitating around a nearby star, dubbed HD 163296. This star is roughly 4 million years old, which makes it practically a baby in terms of cosmic age, since it’s 1,000 times younger than our sun.

Located in the direction of the Sagittarius constellation of the Milky Way, this young star was found to host three “infant planets,” or protoplanets, that are still developing, thanks to a novel planet-finding technique that takes an in-depth look at the protoplanetary disk that typically surrounds newborn stars.

As the Inquisitr previously reported, such young stars are normally shrouded in a cloud of gas and dust, that holds all the necessary ingredients to churn out new planets.

The newly spotted planets appear to be the mass of Jupiter and were detected in the observations of the European Southern Observatory’s (ESO) Atacama Large Millimeter/submillimeter Array (ALMA) in northern Chile. According to the video below, uploaded by ESO, these are the first planets ever to be discovered with ALMA.

Two of the protoplanets were identified by a research team led by Richard Teague from the University of Michigan in Ann Arbor. According to the Astrophysical Journal Letters study detailing the discovery, these planets reside at distances of 80 and 140 astronomical units (AU) from their parent star — 1 AU being the distance between the Earth and the sun, calculated at about 150 million kilometers.

The third protoplanet was picked up by astronomers led by Christophe Pinte of Monash University in Australia. As per the Astrophysical Journal Letters paper describing how it was found, this Jupiter-mass planet stands slightly further away from HD 163296, at a distance of 150 AU.

“Though thousands of exoplanets have been discovered in the last few decades, detecting protoplanets is at the frontier of science,” says Pinte.

Both teams used variations of the same pioneering technique and, together, managed to unravel the mysteries of this newfound planetary system.

While combing through the ALMA data, each team searched for high-resolution images of the newborn star to take a close look at its protoplanetary disk. The next step was to analyze the distribution and motion of a particular type of gas within the disk, namely carbon monoxide (CO).

As Teague’s co-author, Jaehan Bae, explains, the study of gas motion is “crucial” in scoping out new planets.

“Although dust plays an important role in planet formation and provides invaluable information, gas accounts for 99 percent of a protoplanetary disks’ mass,” says Bae, who is a researcher at the Carnegie Institute for Science in Washington, DC.

The reason why the astronomers chose to investigate CO molecules in the protoplanetary disk — instead of going for traditional planet-finding techniques such as the transit method, which looks for dips in the star’s luminosity as an already grown planet passes in front of it — is that they emit a certain type of millimeter-wavelength light that is specific to new-forming planets.

ALMA can pick up these emissions and note if there are any subtle changes in the wavelength of this light, which show if the gas is moving and how it travels through the disk. By studying the motion of the CO gas and the patterns it follows, the astronomers stumbled upon three disturbances in the flow of particles, which could only indicate the presence of planets.

Protoplanetary disk.
3D illustration of a star’s protoplanetary disk, showing the birth of a solar system.

“It would take a relatively massive object, like a planet, to create localized disturbances in this otherwise orderly motion,” notes Pinte.

The astronomers then ran computer models to confirm their observations, which indeed pointed to the discovery of three still forming planets.

“The observed flows fit beautifully with predictions for the flow pattern around a newborn planet a few times the mass of Jupiter,” shows Daniel Price, Pinte’s co-author and colleague at the university.

The new technique could help science understand the intricate processes of planetary formation and reveal potentially countless other planets that can’t be found through other strategies.

As Teague points out, their novel method of finding planets could lead to the discovery of the youngest occupants in the Milky Way.

“This entirely new approach could uncover some of the youngest planets in our galaxy, all thanks to the high-resolution images coming from ALMA.”