HELP NAME
2007 OR10
Help astronomers name the largest unnamed world in our Solar System.
Who are we?
We are 3 astronomers: Meg, Mike, and David. Over ten years ago, we discovered (225088) 2007 OR10 at Palomar Observatory near San Diego, California. We're asking for your help in order to pick the best fitting naming suggestion for 2007 OR10 to submit to the International Astronomical Union (IAU)
Gemini Observatory, Hawai'i
Meg is a planetary scientist and astronomer. She currently is an assistant scientist at Gemini Observatory based in Hilo, Hawai'i. Her research focuses on the small resevoirs in the outer Solar System, Mars, and exoplanets. She studies how planets and building blocks form and evolve, applying ground-based surveys to probe our Solar System’s small body reservoirs and citizen science to mine large datasets for Solar System science. Meg is currently involved in the Planet Four citizen projects ( Planet Four, Planet Four: Terrains , Planet Four: Ridges), and Comet Hunters citizen science project. As a graduate student at Caltech, Meg helped run the Palomar Distant Solar System Survey which discovered 2007 OR10. She has also helped discover and characterize PH1-b: the first exoplanet found in a four star system.
Caltech, California
Mike Brown is the Richard and Barbara Rosenberg Professor of Planetary Astronomy at the Caltech. and has been on the faculty there since 1996. He specializes in the discovery and study of bodies at the edge of the Solar System. Among his numerous scientific accomplishments, he is best known for his discovery of Eris, the most massive object found in the solar system in 150 years, and the object which led to the debate and eventual demotion of Pluto from a real planet to a dwarf planet. He is also one of the first proponents of Planet 9, a proposed Neptune-sized body lurking in the outer Solar System beyond Neptune. Mike was the principal investigator of the Palomar Distant Solar System Survey which discovered 2007 OR10. Mike is also author of "How I Killed Pluto and Why It Had It Coming", an award winning best selling memoir of the discoveries leading to the demotion of Pluto.
David Rabinowitz
Yale University, Connecticut
David is a research scientist at Yale University’s Center of Astronomy and Astrophysics and Physics Department. He is the co-discover of Eris, Haumea, Makemake, and other dwarf planets in the outer Solar System. Since 2003, David has been the principal specialist for the QUEST camera. David was a collaborator on the Palomar Distant Solar System Survey which utilized the QUEST camera. David has also led projects to survey the solar phase curves and rotation states of the largest KBOs and other icy bodies in the solar system and has been a co-investigator in surveys for nearby bright supernovae and studies of Active Galactic Nuclei (AGN) variability.
What is 2007 OR10?
(225088) 2007 OR10 is a minor planet orbiting the Sun beyond Neptune.
Use the tabs below to discover what we know.
- Orbit
- Discovery
- Composition
- Size
- Satellite
- Rotation
2007 OR10's orbit places it in the Kuiper belt, the sea of icy planetesimals that orbit beyond Neptune. Over 3000 Kuiper belt objects (KBOs) are known to date. 2007 OR10 resides on an elliptical orbit. It makes its closest approach to the Sun at 33 au (1 au is the mean distance between the Earth and Sun), and its furthest point from the Sun is at a distance of 101 au. 2007 OR10 has a typical orbit of a scattered disk Kuiper belt object, one that was emplaced into the Kuiper belt during the migration of our Solar System's giant planets, including Neptune, through gravitational scattering. 2007 OR10 appears to be in the 10:3 mean motion resonance with Neptune (2007 OR10 completes 3 orbits for every 10 Neptune orbits).
Image - 2007 OR10's orbit - Credit: Produced by kheider using the Gravity Simulator created by Tony Dunn.
2007 OR10 was discovered on July 17, 2007 as part of the Palomar Distant Solar System Survey that was searching for distant bodies in the Kuiper belt and beyond. The survey employed the 48-inch Samuel Oschin telescope located at Palomar Observatory in Southern California. Moving Solar System bodies were discovered, by taken an image on one night and returning to take a second image ~1-2 hours later and then coming back the next night with another pair of images, with the frames separated by ~1-2 hours. For more information, you can read the research paper summarizing the survey.
Image: Star trails and the Samuel Oschin Telescope - Credit: Palomar/Caltech
We know from previously measured densities/bulk internal compositions of bodies of similar size to 2007 OR10, that the body is likely a mixture of ice and rock. Near-infrared spectroscopy has revealed that there are large quantities of pure water ice and possibly traces of methane ice on 2007 OR10's surface. 2007 OR10 has one of the reddest surfaces ever found in the Kuiper belt. It is suspected that its red hue comes from the irradiation of the trace amounts of methane ice on its surface (similar to dwarf planet-sized Quaoar). It is suspected that water ice on 2007 OR10's surface indicates past cryovolcanism earlier on in the planetesimal's history where water from the interior coated and froze on the surface. For more information, you can read the research paper summarizing this result.
Image: Artist rendition of 2007 OR10 - Credit: NASA
We don't quite know 2007 OR10's size accurately, but a good guess is that 2007 OR10 is ~ 1250 km in diameter. That makes it smaller than Pluto and Eris and some of the other Pluto-sized KBOs, but that size estimate earns 2007 OR10 a spot on the list of the top 10 largest KBOs. 2007 OR10 is likely large enough for gravity to make it round, making it a candidate dwarf planet.
Image: A Family Portrait of the Largest Kuiper belt Objects - Artist Rendition Credit: Lexicon - based on an a graphic created by: NASA, ESA, and A. Feild (STScI)
In 2016, it was announced that a moon had been discovered orbiting around 2007 OR10 by Csaba Kiss and collaborators using archival data from the Hubble Space Telescope. Many of the large bodies in the Kuiper belt have small moons, including Eris, Haumea, Makemake, and and Quaoar.
For more information you can read the research paper summarizing this discovery and this Planetary Society post by Emily Lakdawalla.
Image - Discovery images of 2007 OR10's moon taken by the Hubble Space Telescope - Credit: NASA, ESA, C. Kiss (Konkoly Observatory), and J. Stansberry (STScI)
András Pál and collaborators have measured the rotational light curve for 2007 OR10 thanks to the Kepler spacecraft and NASA's K2 mission . Measuring the brightness of 2007 OR10 over a 19 day period, Pál and collaborators find that 2007 OR10 rotates very slowly with a 44.81 hour rotation period; one of the slowest rotation periods measured in the Kuiper belt.
For more information you can read the research paper about the K2 analysis.
Video - A subset of Kepler's pixels downloaded monitoring where 2007 OR10 was expected to be in K2's observing campaign. This video shows all the observations Kepler took of 2007 OR10 in 2014. The arrow shows the position of 2007 OR10 in each K2 frame over 19 days The motion of 2007 OR10 is caused by Kepler's motion as the spacecraft orbits the Sun. - Credit: Konkoly Observatory/László Molnár and András Pál