Massive spiral arms in dust around young stars are the evidence for the presence of giant, invisible worlds
European Southern Observatory’s telescope has spotted massive spiral arms around two newborn stars, SAO 206462 and MWC 758. The strange pattern had been observed in many other young stars as well. Previously, astronomers were unable to provide convincing explanations about the formation of these mysterious spirals. Now, they claim it may be the evidence for the presence of giant planets which are hidden or invisible.
Astronomers don not know much about the early stages of a planet’s formation because planets born inside a huge, pancake shaped disc of dust and gas, known as circumstellar disks. The latest research suggests that the spiral patterns are actually generated by these unseen, newborn planets.
“It’s difficult to see suspected planets inside a bright disk surrounding a young star. Based on this study, we are convinced that planets can gravitationally excite structures in the disk,” said Ruobing Dong from Lawrence Berkeley National Laboratory.
“So if you can identify features in a disk and convince yourself those features are created by an underlying planet that you cannot see, this would be a smoking gun of forming planets.
Astronomers came up with the striking explanation after detailed computer modeling of how these dust and gas disks around newborn stars are evolved. Stars are created by dense concentrations of interstellar gas and dust known molecular clouds and for many stars, a circumstellar disk of gas and dust particles, used to hang around the star for a few million years after the formation.
Gaps and rings in circumstellar disk indicate there could be many invisible planets embedded in it but it’s difficult to estimate their numbers and masses and to spot their locations earlier. But now with the help of computer generated simulations, astronomers believe they might have solved the mystery.
If there is no planet present, the disk would look smooth, rather than generating spiral waves. “Simulations also suggest that these spiral arms have rich information about the unseen planet, revealing not only its positions but also its mass,” said Zhaohuan Zhu of Princeton University.
“To make the grand scale spiral arms seen in the SAO 206462 and MWC 758 systems, the unseen planet whould have to be bulky, at least 10 times the mass of Jupiter, the largest planet in our solar system.”
A closer look at the features of spiral arms can help understand how and when planets were formed.
“There are many theories about how planets form but very little work based on direct observational evidence confirming these theories,” Dong said. “If you seen signs of a planet in a disk right now, it tells you when, where, and how planets form.
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Source: Hubble Site