Although much rarer, another example of a potential target is an interstellar interloper from another star system, like the famed ‘Oumuamua that flew past our Sun on a highly inclined orbit in 2017. Studying an interstellar object would offer the chance to explore how comet-like bodies form and evolve in other star systems.

No one knows where it came from, but it’s here now. And the chase is on.

Astronomers around the world are monitoring an interstellar comet hurtling through the solar system, known for the moment as C/2019 Q4. It’s the second time in less than two years they’ve seen an object from another star swing through our cosmic neighborhood.

...more @ link above...

newolder wrote:Everything (else) we know about Interstellar visitor #2 so far, posted @ The Atlantic

No one knows where it came from, but it’s here now. And the chase is on.

Astronomers around the world are monitoring an interstellar comet hurtling through the solar system, known for the moment as C/2019 Q4. It’s the second time in less than two years they’ve seen an object from another star swing through our cosmic neighborhood.

...more @ link above...

Cito di Pense wrote:...

It's interesting of course, but I'm not going to be surprised if objects like this now are tracked regularly, assuming they show up at all. I think our instrumentation, data processing, and sets of eyes on those data are now up to the task. If these actually are rare events, the absence of evidence is not going to convince anyone.

newolder wrote:

Cito di Pense wrote:...

It's interesting of course, but I'm not going to be surprised if objects like this now are tracked regularly, assuming they show up at all. I think our instrumentation, data processing, and sets of eyes on those data are now up to the task. If these actually are rare events, the absence of evidence is not going to convince anyone.

Part of my reasoning to add this to the first rather than start a new topic for each - I'm guessing that improvements and additions to sky watching technology will lead inevitably to more such discoveries. Comets and small asteroids are interesting enough but there's also an estimated 50 billion rogue planets (not bound in stellar orbits) wandering about the Milky Way too.

Outlook: Look out!

Interstellar Comet Borisov Looks Pretty Normal, New Observations Suggest

Observations of the interstellar Comet 2I/Borisov have been flooding in for six weeks, and the more astronomers duplicate one another's work, the more confident they are in their analysis of the object.

The prestigious journal Nature Astronomy has now published one of the earlier papers based on this frantic rush of observations. The new paper both confirms that Comet Borisov comes from outside our solar system and offers preliminary evidence suggesting that the object isn't very different from the comets that clutter our own solar system.

When an object as interesting as an interstellar comet comes around, astronomers are bound to swing into action to study it as much as possible, so the scientists behind the new paper are hardly the only ones reaching similar conclusions about the object.
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