Dwarf planet lurking beyond Neptune's orbit is far larger than expected

The new study made use of data from both the Kepler and Herschel space telescopes(Credit: NASA/JHUAPL/SwRI)

According to a team of astronomers making use of data from two powerful orbital telescopes, a dwarf planet known as 2007 OR10 orbiting in the far reaches of our solar system is significantly larger than previously believed. The results of the study makes the little-known planetoid the third largest dwarf planet behind Pluto and Eris.

Previous observations of 2007 OR10 using only infrared data from the Herschel telescope had estimated the dwarf planet to have a diameter of around 795 miles (1,280 km). However, these readings were taken without knowledge of 2007 OR10's rotational period, which is a key variable needed for astronomers to extrapolate the size of a heavenly body.

Without this key variable, the light detected by a telescope could lead to incorrect estimations of a planetoid's size, as was the case with 2007 OR10. A smaller body with a brighter surface could potentially appear larger than a darker, much larger dwarf planet.

The new research paired infrared readings collected by Herschel with visible light data harvested by the Kepler spacecraft, which was tasked with observing 2007 OR10 for a continuous period of 19 days in late 2014. The combination of the data sets allowed astronomers to deduce a number of characteristics of the distant planetoid.

It is now estimated that 2007 OR10 boasts a diameter of 955 miles (1,535 km), and takes an impressive 45 hours to complete a day cycle. The researchers believe that the surface of 2007 OR10 is coated with methane ices, carbon monoxide and nitrogen, which would likely bestow the planetoid with a dark reddish hue.

The increase in size of 2007 OR10 has also increased the expected gravitational influence of the planet, meaning that it could be capable of holding on to the above materials where a smaller planetoid would have lost them to space over time.

Now that we know a little more about 2007 OR10, it's probably time that it be given a more catchy name. As is tradition, the honour of naming the dwarf planet will go to its discoverers, Meg Schwamb, Mike Brown, and David Rabinowitz.

"The names of Pluto-sized bodies each tell a story about the characteristics of their respective objects. In the past, we haven't known enough about 2007 OR10 to give it a name that would do it justice," comments Schwamb. "I think we're coming to a point where we can give 2007 OR10 its rightful name."

A paper on the research can be found online in the Astronomical Journal.

Source: NASA

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