Centaurs in astronomical terms are space rocks which have the characteristics of asteroids and comets. It is believed they originated from beyond the orbit of Neptune and travelled inwards towards the Sun.
They rummaged around the solar system for millions of years and were the responsible for Late Heavy Bombardment from about 3.8 billion years ago when asteroids rained down on Earth.
They have the same rocky body of an asteroid, while they emit gas and vapour in their tale, known as a coma, much like a comet.
It is when these gasses are chemically present that centaurs are considered active, and only 18 of these active centaurs have been found since the first was discovered in 1927.
Now another can be added to the list after astronomers discovered Centaur 2014 OG392 lurking in near to the orbit of Jupiter.
Finding and keeping a centaur in view is notoriously difficult as they are millions of miles away and orbit within hundreds of thousands of space rocks.
Researchers found the latest centaur by analysing archival images from an array of telescopes, as well as new data gathered from the Dark Energy Camera at the Inter-American Observatory and the Walter Baade Telescope at the Las Campanas Observatory.
Astronomer Colin Chandler, from the Northern Arizona University, said: “Our paper reports the discovery of activity emanating from Centaur 2014 OG392, based on archival images we uncovered, plus our own new observational evidence acquired with the 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 developed a novel technique that combines observational measurements – for example, colour, and dust mass – with modelling efforts to estimate such characteristics as the object’s volatile sublimation and orbital dynamics.”
According to the research published in Astrophysical Journal Letters, the technique involves using a specially developed algorithm which looked for evidence of solids being transformed into gasses, which leaves behind the coma.
Mr Chandler added: “We detected a coma as far as 400,000 km [248,548 miles] 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.
“We developed a novel technique that combines observational measurements, for example, colour and dust mass, with modelling efforts to estimate such characteristics as the object’s volatile sublimation and orbital dynamics.”
Such is the activity coming from the closely monitored centaur that astronomers at the Minor Planet Center have reclassified it as a comet and will be known as “C/2014 OG392 (PANSTARRS).”
Mr Chandler added: “I’m very excited that the Minor Planet Center awarded a new comet designation befitting the activity we discovered on this unusual object.”
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World news – GB – Centaur discovered lurking deep in the solar system