Hubble Spots Moon Around Third Largest Dwarf Planet

[bystander]

Hubble Spots Moon Around Third Largest Dwarf Planet
NASA | STScI | HubbleSite | 2017 May 18

[img3="Credit: NASA, ESA, C. Kiss (Konkoly Observatory), and J. Stansberry (STScI)"]http://imgsrc.hubblesite.org/hvi/upload ... 40x720.png[/img3][hr][/hr]

Beyond the orbit of Neptune lies a frigid, dark, vast frontier of countless icy bodies left over from the solar system's construction 4.6 billion years ago. This region, called the Kuiper Belt, was hypothesized by astronomer Gerard Kuiper in 1951. But it took another four decades for astronomers to confirm its existence. The largest bodies are called dwarf planets, with Pluto being the biggest member. Pluto is so big, in fact, that it was discovered 60 years before other Kuiper worlds were detected. Moons around dwarf planets are elusive, though. Pluto's moon Charon wasn't found until the mid-1970s.

Now, astronomers have uncovered a moon around another dwarf planet by using the combined power of three space observatories, including archival images from the Hubble Space Telescope. Called 2007 OR₁₀, it is the third-largest dwarf planet in the Kuiper Belt. With this moon's discovery, most of the known dwarf planets in the Kuiper Belt larger than 600 miles across have companions. These bodies provide insight into how moons formed in the young solar system. In fact, there is an emerging view that collisions between planetary bodies can result in the formation of moons. Based on moon rock samples from NASA's Apollo mission, astronomers believe that Earth's only natural satellite was born out of a collision with a Mars-sized object 4.4 billion years ago.

Discovery of Hungarian and American astronomers tells about the past of the solar system
Hungarian Academy of Sciences | 2017 May 18

Discovery of a Satellite of the Large Trans-Neptunian Object (225088) 2007 OR₁₀ - Csaba Kiss et al

• Astrophysical Journal Letters 838(1):L1 (20 Mar 2017) DOI: 10.3847/2041-8213/aa6484
  arXiv.org > astro-ph > arXiv:1703.01407 > 04 Mar 2017

[bystander]

Hubble Images of 2007 OR₁₀
ESA Hubble | 2017 May 19

[img3="Credit: NASA, ESA, C. Kiss (Konkoly Observatory), and J. Stansberry (STScI)"]https://cdn.spacetelescope.org/archives ... o1718b.jpg[/img3][hr][/hr]

This sequence of images, taken by the NASA/ESA Hubble Space Telescope's Wide Field Camera 3, shows a moon circling the dwarf planet 2007 OR₁₀. The top four images were taken on 6 November 2009; the bottom four on 18 September 2010.

As 2007 OR₁₀ orbits the Sun, it changes position with respect to the background stars (the bright objects that change from panel to panel). The snapshots reveal that the moon moves with the dwarf planet, proving that it is gravitationally bound to the larger body.

2007 OR₁₀ is the third-largest known dwarf planet, behind Pluto and Eris, and the largest unnamed world in the Solar System. The pair is located in the Kuiper Belt, a realm of icy debris left over from the solar system's formation.

The dwarf planet is about 1520 kilometres across; the moon is estimated to be 240 kilometres to 400 kilometres in diameter. 2007 OR₁₀, like Pluto, follows an eccentric orbit, but it is currently three times farther than Pluto is from the Sun.

Moon Around the Dwarf Planet 2007 OR₁₀
ESA Hubble | 2017 May 19

[neufer]

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<<2007 OR₁₀ was discovered by California Institute of Technology astronomers as part of the PhD thesis of Megan E. Schwamb, who was at the time a graduate student of Michael E. Brown. Brown nicknamed the object "Snow White" for its presumed white color, because it would have to be very large or very bright to be detected by their survey. It was also the "seventh dwarf" discovered by Brown's team, after Quaoar in 2002, Sedna in 2003, Haumea and Orcus in 2004, and Makemake and Eris in 2005. However, 2007 OR₁₀ turned out to be one of the reddest objects in the Kuiper belt, comparable only to Quaoar, so the nickname was dropped. 2007 OR₁₀ is currently the largest known object in the Solar System without an official name.>>
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<<"Snow-White and Rose-Red" (German: Schneeweißchen und Rosenrot) is a German fairy tale collected by the Brothers Grimm. During the summer, when the girls are walking through the forest, they find a dwarf whose beard is stuck in a tree. The girls rescue him by cutting his beard free, but the dwarf is ungrateful and yells at them for cutting his beautiful beard. The girls encounter the dwarf several times that summer, rescue him from some peril each time and the dwarf is ungrateful each time.>>