An article published in “The Astronomical Journal” describes a research on a trans-Neptunian object called 2007 OR10. A team of astronomers used NASA’s Kepler space telescope and archive data of ESA’s Herschel space telescope’s observations to study this celestial body. The result is that they discovered that it’s much bigger than it looked and is probably a dwarf planet.
The Kepler space telescope is generally used to detect planets in other solar systems but in the mission called K2 is also used to observe other types of objects. Putting together observations of 2007 OR10 made with Kepler and data collected in the course of the Herschel space telescope mission it was possible to get a lot of information about the physical characteristics of this celestial body.
2007 OR10, or more precisely (225088) 2007 OR10, is a scattered disc object, a category of trans-Neptunian objects that is part of a region rich of icy planetoids. According to the new research it’s quite dark and has a slower rotation than almost any other celestial body in the solar system with a 45-hour day.
According to previous estimates, the diameter of 2007 OR10 was about 1,280 kilometers (795 miles) but according to the revised estimate it’s about 1,535 kilometers (955 miles). For a comparison, Pluto and Eris, the two largest dwarf planets of the solar system, have a diameter of just over 2,300 kilometers (1,400 miles). Right now its distance from the Sun is about 87 times that of Earth.
The rotation of 2007 OR10 was studied using the Kepler space telescope, which needs to detect very small changes in brightness in a celestial body in its planet hunting activities. While Kepler made it possible to measure the fraction of sunlight reflected by 2007 OR10, Herschel allowed to measure the fraction absorbed and then emitted as heat. Putting together the various data it was possible to build a model which provided a more precise estimate of this celestial body’s size.
At first, astronomers thought that 2007 OR10 was brilliant but its light is reflected by a surface larger than expected so in the end it turns out to be rather dark, more than the known dwarf planets. According to previous observations made with ground-based telescopes it has a red color, which could be due to the presence of methane ice on its surface. The new information suggest that there are also frozen carbon monoxide and nitrogen.
2007 OR10 was discovered in 2007 using the Samuel Oschin Telescope at Palomar Observatory by astronomers Meg Schwamb, Mike Brown, and David Rabinowitz, who have the honor of giving it a real name. It will also be necessary to re-evaluate its status and that’s up to the IAU (International Astronomical Union). Probably it will be classified as a dwarf planet.