“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, initially D. Farnocchia (JPL), W. Gray, and D. Tholen (UoH).”
Remember ‘Oumuamua, the first interstellar object ever discovered in our solar system? You won’t for long as another one was picked up by multiple observers and reported this week by The Minor Planet Center (MPC) at Harvard University. Unlike ‘Oumuamua, this one is definitely a comet and has been identified earlier enough in its trip through the solar system to be analyzed intensely – possibly revealing where it came from and how astronomers can locate more of them.
“The comet’s current velocity is high, about 93,000 mph [150,000 kph], which is well above the typical velocities of objects orbiting the sun at that distance. The high velocity indicates not only that the object likely originated from outside our solar system, but also that it will leave and head back to interstellar space.”
The BBC reports that object gb00234, now known as Comet C/2019 Q4, was discovered by amateur (but experienced) astronomer Gennady Borisov on August 30th, 2019, at the Crimean Astrophysical Observatory in Bakhchysarai. When he noticed it, C/2019 Q4 was three astronomical units (450 million km) from the Sun. Since then, other astronomers have seen its tail – confirming C/2019 Q4 is a comet – and measured its eccentricity at 3.2, based on current observations. A perfect circle has an eccentricity of 0, while a closed elliptical orbit ranges from 0 to 1. Anything greater than one indicates an arc-shaped trajectory and is likely an interstellar comet or object making a one-time visit. While not confirmed yet, together these make Comet C/2019 Q4 the first ‘true’ comet to visit use from outside our solar system.
Unless it’s a spaceship.
Good point. Anyone?
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.
Astrophysicist Karl Battams, from the Naval Research Laboratory in Washington DC, tweeted an end to that comet-asteroid-spaceship-or-what debate which has trailed ‘Oumuamua like a tail (if it had one) since it was discovered hightailing out of here. Comet C/2019 Q4 will have plenty of eyes on it as it will be visible to even low-powered professional telescopes for at least a year, including when it makes its turn around the sun (perihelion) around December 10. However, the MPC leaves an opening for the unusual:
"Absent an unexpected fading or disintegration, [C/2019 Q4] should be observable for at least a year."
In lieu of seeing windows with aliens waving out of them, an “unexpected disintegration” would be the next coolest thing.