Objects in space aren’t exactly marked as planets or simply rocks. A lot of time and research goes into determining whether something belongs to a planetary class or something entirely else.
Recently, a team led by Colin Chandler, doctoral student and Presidential Fellow at Northern Arizona University’s (AU) Astronomy and Planetary Science PhD program, noticed some activity from an object classified as Centaur 2014 OG392. The planetary object was discovered around 2014. However, they noticed some activity that isn’t always associated with planets or Centaurs.
Centaurs are kind of minor planets. Most astronomers believe they originated in the outer solar system in Kuiper Belt. Sometimes they have features similar to a comet-like comae – a dust and gas cloud trail. This is an unlikely feature because they generally orbit around Jupiter and Neptune – an area too cold to allow sublimation of water or transition solid to a gas. Around 18 known Centaurs have been observed since 1927 and they remain largely a mystery.
Most of the time, Centaur activity goes unmonitored because it’s a challenging process. The activity is usually very faint, and it requires time-intensive telescopic observation as they are very rare. However, Chandler’s team dedicated all their time observing this unusual activity emanating from this Centaur. They also created an exhaustive database with archival images as well as observational data.
The new evidence was from Dark Energy Camera at the Inter-American Observatory in Cerro Tololo, Chile, the Walter Baade Telescope at the Las Campanas Observatory in Chile and the Large Monolithic Imager at Lowell Observatory’s Discovery Channel Telescope in Happy Jack, Arizona.
“We detected a coma as far as 400,000 km from 2014 OG392 and our analysis of sublimation processes and dynamical lifetime suggest carbon dioxide and/or ammonia are the most likely candidates for causing activity on this and other active Centaurs,” said Chandler.
The team claim to have developed a novel technique – a combination of observing traditional elements like colour and dust mass with new modelling techniques to evaluate more un-observable features like volatile sublimation and orbital dynamics.
As a result of their study published in Astrophysical Journal Letters, the centaur was re-classified. It is now accepted as a comet and named C/2014 OG392 (PANSTARRS). Chandler said he was excited that the minor planet centre gave this former planet a new designation as it “more fitting.”