The illustration of an artist from the very young CI Tau system, which seems to contain four gas giant planets.
Acknowledgments: Amanda Smith, Institute of Astronomy
In an astronomical first four gigantic planets around a very young star were discovered, reports a new study.
The star in question is CI Tau, which is about 500 light-years from Earth. CI Tau is only 2 million years old and is still surrounded by a swirling mass of dust and gas, a protoplanetary disk.
The star was already known to host one planet, a world that is about ten times as massive as Jupiter, which circles CI Tau once every nine days of the earth. This planet, called CI Tau b, was the first "hot Jupiter" ever discovered around such a young star. [Gallery: The Strangest Alien Planets]
In the new study, a team of researchers observed CI Tau and his disk with the Atacama Large Millimeter / submillimeter Array (ALMA), a network of radio telescopes in the Chilean Andes. ALMA saw three extra holes in the disk, at distances of 13, 39 and 100 astronomical units (AU) of the star, the astronomers report. (One AU is the distance between the earth and the sun – about 93 million miles or 150 million kilometers).
So it seems that CI Tau b has three brothers and sisters. And these new worlds are also great: the team's work suggests that the innermost of the three is about as massive as Jupiter, while the outer two have Saturn-like faces.
Astronomers had never seen four gas giant planets around such a young star, said the members of the study team. And the orbital range – the outer planet is about 1000 times further from CI Tau than the inner world – is also extreme, the researchers added.
Indeed, it is unclear how the two outer planets could take shape.
"Saturn-mass planets are thought to form by first collecting a solid core and then pulling a layer of gas on top, but these processes should be very slow at great distances from the star," wrote lead author Cathie Clarke, of the Institute of Astronomy at the University of Cambridge in England, said in a statement. "Most models will struggle to make planets of this mass at this distance."
It is also unclear what role, if any, the brothers and sisters played planets when piloting CI Tau b to his super-tight orbit, according to the members of the study team. Observing the bizarre system further with other telescopes can help answer these and other questions, according to the members of the study team.
The new article was published this month in The Astrophysical Journal Letters.
Mike Wall's book on the search for extraterrestrial life, "Out There," will be published on November 13 by Grand Central Publishing. Follow him on Twitter @michaeldwall. follow us @Spacedotcom or Facebook. Originally published on Space.com.