The 2007 OR10 is the third-biggest of the solar system's nine dwarf planets and is also called "Snow White." Astronomers discovered a small moon that is orbiting our solar system's third-largest dwarf planet.

The astronomers found the moon orbiting 2007 OR10 thanks to images that were taken from NASA's Hubble Space Telescope, as well as two other space observatories.

2007 OR10: The 'Snow White' Dwarf Planet

The Snow White is basically a 950-mile wide dwarf planet, which is located in the Kuiper Belt. This is the ring of icy debris that is found beyond Neptune and was left over when the solar system formed 4.6 billion years ago. According to astronomers, the Snow White dwarf planet's moon is quite big and the satellite has a 150- to 250-mile wide diameter.

The 2007 OR10 is only smaller than two other dwarf planets — Eris and Pluto. The 2007 OR10 was discovered roughly 10 years ago and has a 950-mile diameter. This dwarf planet has a "eccentric orbit" and it is three times further from the sun vis-à-vis Pluto.

Hubble Space Telescope Discovers Moon Orbiting 2007 OR10

NASA shared that the latest discovery offers an insight into how satellites formed in the young solar system. The study's lead author Csaba Kiss remarked that finding satellites around the known bigger dwarf planets — barring Sedna — suggests that when their formation occurred, the collision were likely "more frequent." This is possibly a constraint for the satellites' formation model.

The researchers spotted the 2007 OR10's satellite in archival images, which the Hubble Space Telescope's camera captured. However, the Kepler Space Telescope was the first to tip the astronomers of the possibility of a moon orbiting the dwarf planet. The data from this telescope revealed that the Snow White dwarf planet rotated once every 45 hours on its axis. Its rotation rate is a lot slower than objects in the Kuiper Belt, which have a rotation rate of under 24 hours.

"We looked in the Hubble archive because the slower rotation period could have been caused by the gravitational tug of a moon. The initial investigator missed the moon in the Hubble images because it is very faint," Kiss remarked.

The moon orbiting 2007 OR10 was spotted in two different observations of Hubble images. These observations had a year's gap between them and were taken in Nov. 6, 2009, and Sept. 14, 2010 from the Hubble's Wide Field Camera 3. The images showed that the third-largest dwarf planet's moon — set against a star-spangled backdrop — was bound gravitationally to 2007 OR10 as it moves with the planetary body.

Unfortunately, the two Hubble image observations were not adequate to offer astronomers sufficient clues to ascertain an orbit.

The research's results were published in The Astrophysical Journal Letters.

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