Alma captures the protoplanetary disc that has formed around the star HL Tau. The new research confirms that the gaps were formed by young planets. Photo by ALMA/ESO/NAOJ/NRAO
TORONTO, May 5 (UPI) -- It's settled. The controversial image of HL Tau, a young star and its surrounding disc of gas and dust, does indeed show planet formation.
When the image -- captured by ALMA, a massive radio telescope in the Atacama desert of northern Chile -- was released in October 2014, it sparked debate among scientists as to what exactly was responsible for the orbital gaps in the gaseous circumstellar disk.
Many agreed the image showed early planet formation, but some dissenters argued the gaps were too close together to have been formed by planets. New analysis, however, by astrophysicists at the University of Toronto proves the gaps are indeed carved by young planets.
High-resolution imagery of the HL Tau's protoplanetary disc confirmed the paths of the planets were consistent with a planetary system operating under the parameters of what's called orbital resonance.
Orbital resonance, or resonant configuration, is a concept that explains how bodies with overlapping or intimate orbits exert periodical gravitational influence on their neighbors in a way that allows them to avoid collision.
"The system can be much more stable in a resonant configuration, and it's a natural state for planets in the HL Tau system to migrate to," lead study author Daniel Tamayo, a scientist at Toronto's Center for Planetary Science and the Canadian Institute for Theoretical Astrophysics, explained in a press release.
Because systems like HL Tau -- a young star located 450 light-years from Earth in the constellation Taurus -- is shrouded in gas and dust, observing its resident bodies is difficult. But Tamayo and his colleagues were able generate high-resolution imagery of the system by using a series of telescopes, each several miles apart, capable of observing longer wavelengths. The data from each telescope is pieced together to form detailed imagery of their cosmological target.
"We've discovered thousands of planets around other stars, and a big surprise is that many of the orbits are much more elliptical than those found in our solar system," Tamayo explained.
He says the new imaging technique will allow scientists to better understand whether the egg-shaped orbits of HL Tau's young planets are actually the norm -- and Earth's spherical path is a relative oddity.
"If further observations show these to be the typical starting conditions around other stars, it would reveal our solar system to be a remarkably special place," Tamayo added.
The new research is scheduled to be published in the Astrophysical Journal.