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Did We Miss an Interstellar Comet Four Years Ago? (arxiv.org)
Long-time Slashdot reader RockDoctor writes: A paper published on Arxiv last week reports on a project to redetermine the "orbits of long period comets... We recently attempted to check, whether the assumption of a parabolic orbit for hundreds of comets discovered after 1950 is fully justified in all cases." The full work by Królikowska & Dybczynski remains in preparation (which is perfectly normal), but this intriguing result deserved early attention.
During this research we found an interesting case of the comet C/2014 W10 PANSTARRS.
(that's the 10th reported comet in fortnight W of year 2014, source : the PANSTARRS team)
After discovery on 2014-11-25, fourteen observations were made over three days, giving a first-estimate orbit with an eccentricity of 0.6039453. So far, so boring — as the temporary designation suggests, these get found on most days. But that orbit is subject to uncertainty so some more measurements were made on 2014-12-22 from a different observatory. When all of the data is considered, it becomes impossible to clearly assign an orbit to this object (this is possible if, for example, there is a fragmentation of the object between observations), but many of the solutions which can be obtained have a hyperbolic orbit — that is, the object is extra-solar.
If correct, this "post-covery" would double the size of the catalogue of interstellar objects known.
Unfortunately, the quality of the original data remains poor — estimates of the orbital eccentricity vary between 1.22 and 1.65 — which is in contrast to the prompt recognition and intense observation campaign for 'Oumuamua. The report's main conclusion is that
Our main purpose is to show that similar cases should be treated in future with greater care by more reliable preliminary orbit determination and alerting observers about the importance of the object to initiate more follow-up observations.
Which is exactly what happened with 'Oumuamua.
During this research we found an interesting case of the comet C/2014 W10 PANSTARRS.
(that's the 10th reported comet in fortnight W of year 2014, source : the PANSTARRS team)
After discovery on 2014-11-25, fourteen observations were made over three days, giving a first-estimate orbit with an eccentricity of 0.6039453. So far, so boring — as the temporary designation suggests, these get found on most days. But that orbit is subject to uncertainty so some more measurements were made on 2014-12-22 from a different observatory. When all of the data is considered, it becomes impossible to clearly assign an orbit to this object (this is possible if, for example, there is a fragmentation of the object between observations), but many of the solutions which can be obtained have a hyperbolic orbit — that is, the object is extra-solar.
If correct, this "post-covery" would double the size of the catalogue of interstellar objects known.
Unfortunately, the quality of the original data remains poor — estimates of the orbital eccentricity vary between 1.22 and 1.65 — which is in contrast to the prompt recognition and intense observation campaign for 'Oumuamua. The report's main conclusion is that
Our main purpose is to show that similar cases should be treated in future with greater care by more reliable preliminary orbit determination and alerting observers about the importance of the object to initiate more follow-up observations.
Which is exactly what happened with 'Oumuamua.
But these days we're spending a lot more time observing with a lot bigger "light buckets", and reducing the data astrometrically to orbits a lot faster - which makes the recent discoveries (putative) much less surprising. We can look forward, on this basis, to seeing yearly or more frequent discovery of interstellar objects - exactly as we did with pulsars when I was a school kid and we've done with gravity wave astronomy in the last couple of years.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
I'm just an astronomy fan boy, but if something's coming in from the Oort Cloud, isn't that far enough away that all orbits are going to look parabolic to the limits of measurable accuracy? I mean we can barely determine orbits in the Kupier belt, right?
Put my fist through my alarm clock with its ding-dong death inside my ear. - The Blackjacks.