An amateur astronomer has reportedly discovered an interstellar object which has come from outside our Solar System.
If it is found to indeed be from outside Earth’s Solar System, it would be only the second such object, after the 2017 discovery of the elongated object known as Oumuamua.
According to the Minor Planet Center (MPC) at Harvard University, the object appears to have a ‘hyperbolic’ orbit, suggesting it originated in a different planetary system.
‘Hyperbolic’ orbit means the object orbits in a shape that is far from a perfect circle. A perfectly circular orbit would have an eccentricity of zero, most orbits of planets, asteroids and comets have an eccentricity between zero and one. This newly discovered object has an eccentricity of 3.2, according to BBC News.
The interstellar object was first spotted by amateur stargazer Gennady Borisov on August 30, at the Crimean Astrophysical Observatory in Bakhchysarai. When they spotted it, the object was roughly three astronomical units (about 450 million km) away from the sun.
According to the MPC:
This object was reported as a comet candidate by G. Borisov (L51) on Aug. 30 UTC. After posting on the NEOCP/PCCP, confirmation of the cometary nature was provided by numerous observers.
Based on the available observations, the orbit solution for this object has converged to the hyperbolic elements shown below, which would indicate an interstellar origin. A number of other orbit computers have reached similar conclusions
Unlike Oumuamua, which was initially classified as a comet but later reclassified as it lacked characteristic comet qualities, the new object bears a clearly visible tail and coma (a ‘fuzzy envelope’ around the nucleus of the comet), which are telltale signs.
According to observations, the new object is very bright and around 20km wide.
The MPC asked astronomers to make follow-up observations, saying ‘an unexpected fading or disintegration should be observable for at least a year’.
Astrophysicist Karl Battams, from the Naval Research Laboratory in Washington DC, tweeted:
It has a name, and is – as such – now official. Comet C/2019 Q4 (Borisov) *appears* to be an interstellar comet! However, the observing arc is still short and the crucial part of the orbit info (eccentricity) still fuzzy. More obs needed to clear this up.
He added:
Unlike ‘Oumuamua, whose asteroid-or-comet nature still gets debated, this one is definitely a comet. If it is unequivocally interstellar, it’ll be fascinating to see how its composition (spectral properties) compare to the variety we see in comets from our own solar system.
As National Geographic points out, the comet is travelling too quickly to be captured by the sun’s gravity, reinforcing the notion it has come from a different planetary system.
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Charlie Cocksedge is a journalist and sub-editor at UNILAD. He graduated from the University of Manchester with an MA in Creative Writing, where he learnt how to write in the third person, before getting his NCTJ. His work has also appeared in such places as The Guardian, PN Review and the bin.