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

By Anthony Wood

May 12, 2016

Dwarf planet lurking beyond Ne...

The new study made use of data from both the Kepler and Herschel space telescopes

NASA/JHUAPL/SwRI

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The new study made use of data from both the Kepler and Herschel space telescopes

NASA/JHUAPL/SwRI

According to a team ofastronomers making use of data from two powerful orbital telescopes,a dwarf planet known as 2007 OR10 orbiting in the far reaches of oursolar system is significantly larger than previously believed. Theresults of the study makes the little-known planetoid the thirdlargest dwarf planet behind Pluto and Eris.

Previous observationsof 2007 OR10 using only infrared data from the Herschel telescope hadestimated the dwarf planet to have a diameter of around 795 miles(1,280 km). However, these readings were taken without knowledge of2007 OR10's rotational period, which is a key variable needed forastronomers to extrapolate the size of a heavenly body.

Without this keyvariable, the light detected by a telescope could lead to incorrectestimations of a planetoid's size, as was the case with 2007 OR10. Asmaller body with a brighter surface could potentially appear largerthan a darker, much larger dwarf planet.

The new research pairedinfrared readings collected by Herschel with visible light dataharvested by the Kepler spacecraft, which was tasked with observing2007 OR10 for a continuous period of 19 days in late 2014. Thecombination of the data sets allowed astronomers to deduce a numberof characteristics of the distant planetoid.

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

The increase in size of2007 OR10 has also increased the expected gravitational influence ofthe planet, meaning that it could be capable of holding on to theabove materials where a smaller planetoid would have lost them tospace over time.

Now that we know alittle more about 2007 OR10, it's probably time that it be given a morecatchy name. As is tradition, the honour of naming the dwarf planetwill go to its discoverers, Meg Schwamb, Mike Brown, and DavidRabinowitz.

"The names ofPluto-sized bodies each tell a story about the characteristics oftheir respective objects. In the past, we haven't known enough about2007 OR10 to give it a name that would do it justice," commentsSchwamb. "I think we're coming to a point where we can give 2007OR10 its rightful name."

A paper on the researchcan be found online in the Astronomical Journal.

Source: NASA

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Anthony Wood

Anthony is a UK-based writer and recent law school graduate who also has a degree in Ancient History, for some reason or another, and a passion for anything do to with space.

1 comment

DianaLangie May 16, 2016 02:58 PM

I will begin by saying I do not doubt the competence of ESA researchers in the slightest. I am epecially impressed by the agency after the ESA promised to land a spacecraft on a breakneck asteroid, without crashing the craft, by 2014 before a prototype blueprint had so much as been printed. I waited patiently for the announcement that it would take a bit longer before the craft was ready as the months rolled along into 2014. The ESA certainly showed me what's what. Lo and behold, much more was accomplished, I'd say, than the initial promise, for not only was the craft built without error- despite being the first of its kind- but the mission was a beautiful success, completed right on time, and -brace yourself- under budget! A complimentary nod was never more well-earned. However, unlike ESA researchers, I am not an astrophysicist. Yet as soon as I read, "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)," in Mr. Wood's article, all that followed was already clear to me. After all, I hear it's chilly out beyond Neptune, and my first thought was that a lot of IR wavelengths would not reflect off 2007 OR10 to make it back to the Herschel's sensors. I wondered why IR measurements were thought to be sufficient to approximate the dwarf planet's size in the first place. It's not as if a celestial body is mammalian...?
Finally, haven't we discussed about a gajillion times that Neptune's otherwise inexplicable inconsistent-appearing orbit indicates the presence of multiple sizeable planetoids beyond Pluto? It's been said, and with some confidence at the very least, that masses unseen must exist on the edge of our Solar System because their gravitational fields are just barely perceptible as affecting Neptune's motions.