You don’t need the latest and greatest telescope to make a discovery. In February, National Research Council of Canada’s Dr. JJ Kavelarrs was looking over a set of images taken by the Canada-France-Hawaii Telescope when he noticed a small dot moving against the background of stars.
He had just found RR245, a new dwarf planet.
“There it was on the screen – this dot of light moving so slowly that it had to be at least twice as far as Neptune from the Sun,” said Dr. Michele Bannister of the University of Victoria.
The Canada-France-Hawaii Telescope captured the images of RR245 as part of the Outer Solar System Origins Survey.
Bannister tells us why astronomers hunt for these distant, icy worlds. “The icy world beyond Neptune trace how the giant planets formed and then moved out from the Sun. They let us piece together the history of our Solar System. But almost all of these icy worlds are painfully small and faint: it’s really exciting to find one that’s large and bright enough that we can study it in detail.”
Last year’s New Horizons flyby of Pluto showed us these worlds are so much more than just icy rocks. They are home to unique geology that we couldn’t even dream of. From ice mountains to floating hills of nitrogen, Pluto amazed.
But what do we know about RR245? Not much. The team of astronomers aren’t even sure of its size. Right now, they estimate it to be about 700 kilometers in size (434 miles). That’s smaller than Pluto (2,372 kilometers) and slightly smaller than Ceres (950 kilometers). And that’s if the estimate is even correct. Astronomers will need to study this dwarf planet more to get a concrete answer.
Did You Know: RR245 might be one of the last dwarf planets we find for a while. Astronomers believe they have found most of the larger, brighter dwarf planets lurking in the Kuiper Belt. To find the rest, bigger and more advanced telescopes are needed. One such telescope is under construction right now atop a mountain in northern Chile. The Large Synoptic Survey Telescope is expected to begin full science operations in 2022.
“It’s either small and shiny, or large and dull,” said Bannister.
What astronomers do know is that it takes RR245 700 years to complete one orbit around the Sun. Timing is everything with these kind of discoveries and time was on the team’s side. RR245 is closing in on its closest point to the Sun after spending hundreds of years more than 80 AU (astronomical units) from the Sun. Around 2096, the dwarf planet will be just 34 AU away from the Sun. At least, that’s the guess right now. The orbital figures will be tweaked the longer we observe RR245.
An old telescope making new discoveries
The Canada-France-Hawaii Telescope spotted RR245 as part of the Outer Solar System Origins Survey (OSSOS).
“OSSOS was designed to map the orbital structure of the outer Solar System to decipher its history,” said Prof. Brett Gladman of the University of British Columbia in Vancouver. “While not designed to efficiently detect dwarf planets, we’re delighted to have found one on such an interesting orbit.”
Gladman heaped praise on the aging telescope. “OSSOS is only possible due to the exceptional observing capabilities of the Canada-France-Hawaii Telescope. CFHT is located at one of the best optical observing locations on Earth, is equipped with an enormous wide-field imager, and can quickly adapt its observing each night to new discoveries we make. This facility is truly world leading,” he said.
The Canada-France-Hawaii Telescope has aged well. When it came online in 1979, the 3.6-meter optical/infrared telescope was known as one of the largest in the world. Today? Modest is probably the right word to use.
The total mass of the telescope comes in at 325 tons. It sits in a 124-foot tall building as it peers into the night’s sky from the summit ridge of Mauna Kea. Many of the world’s most advanced telescopes call this dormant volcano home thanks to the extremely dark and dry skies.
Despite being more than 30 years old, the Canada-France-Hawaii telescope continues to take stunning images of the cosmos.
The Omega Nebula
The Dumbbell Nebula