About 127 light years from Earth, the star HD 10180 was previously determined to have five confirmed planets and two candidate worlds. New analysis has confirmed the two candidate planets and suggests the sun-like star may have another two orbiting it.
If so, the total of nine would outnumber our own solar system total, at eight planets after the "demotion" of Pluto to the status of dwarf-planet.
"The data indicates that there are not only seven but likely as many as nine planets in the system," Mikko Tuomi, an astronomer at the University of Hertfordshire in Britain, told SPACE.com. "The two new planets appear to have orbital periods of roughly 10 and 68 days and masses of 1.9 and 5.1 times that of Earth, which enables the classification of them as hot super-Earths, i.e. planets with likely scorchingly hot rocky surfaces."
Tuomi analyzed observations collected between November 2003 and June 2010 at the European Southern Observatory in La Silla, Chile.
More research will be required to determine whether the final two planets are bona fide worlds and not false signals, he said.
"While the existence of the larger of these two is well supported by the data, the signal corresponding to the smaller one exceeds the detection threshold only barely, which gives it a very small but non-eligible probability of being a false positive," Tuomi said.