Recently, the science news cycle has been fixated on the first interstellar object we’ve
ever seen pass through the solar system, Oumuamua.
Or at least the first large object where we have strong evidence that it did not originate
here.
But it may surprise you to know that on a much smaller scale than an exocomet or asteroid,
or whatever Oumuamua is, we’re literally constantly being bombarded by dust from another
star system entirely.
And, unlike Oumuamua, we know exactly where this material is coming from.
Just 63 light-years from earth is the star Beta Pictoris.
Quite a bit more massive, and significantly more luminous than our sun, this star system
is very young at only 20-26 million years old.
For comparison, by the time this star formed, the dinosaurs, minus the birds, were already
long-extinct on earth by matter of tens of millions of years.
This star also has an extensive proto-planetary debris disk surrounding it as evidenced by
infrared emissions, and a lot of gas as well, and seems to have already have formed, and
may still be forming planets.
Interestingly, this debris disk has actually been directly imaged by astronomers, and it’s
not only dust and gas.
There also appears to be belts of planetessimals, active comets in the system, and even very
young planets.
One of these planets, Beta Pictoris b, is not only confirmed but also directly imaged,
making it one of the few directly imaged exoplanets to date.
Even the star’s disk itself has also been imaged, again one of the few images of stars
that we have that isn’t merely a point of light.
The disk itself bears some oddities that may hint at other planets present in the system.
There is actually a secondary disk of material around the star at an inclined orbit that
seems to be robbing the main disk of material.
One possible explanation for this is that there is a large planet pulling material from
the main disk creating this secondary disk.
Due to the apparent abundance of carbon in this system, these planets would be somewhat
different than our solar system’s composition, where oxygen is more rich, or maybe not.
There are some indications that our own solar system might have had a period where carbon
was more common, as evidenced by certain classes of primitive meteorites, and there’s also
a hypothesis that this excess carbon may have been involved with the formation of Jupiter.
The star itself is noteworthy as well as being visible to the naked eye as the second brightest
star in the constellation pictoris, at least under dark sky conditions.
But our interaction with Beta Pictoris seems to go much deeper than mere visual study,
this star system seems to be shedding some of its dust and bombarding our solar system
with it.
In the year 2000, researchers in New Zealand detect a stream of dust coming into our solar
system from the direction of Beta Pictoris, leading to the possibility that this star
is the main source for interstellar material in our Solar system.
These grains are actually pretty large for dust, and it could be that they are being
ejected from that system by gas giants that may still be migrating unseen within the disk,
or radiation pressure from the star itself is pushing the particles out.
Further study of the Beta Pictoris star system will give us an insight on how star systems
form, including our own.
And if we can ever sample the dust passing through our solar system from beta pictoris,
even more can be learned about the composition of other star systems, in the same grain as
studying interstellar asteroids and comets.
Next time you see a meteor light up the sky, if it’s not associated with a known meteoroid
stream, maybe, just maybe it originated in another star system and you have just witnessed
the end of an interstellar object that left Beta Pictoris long ago.
Thanks for listening!
I am science fiction author and futurist John Michael Godier currently musing about how
messy the galaxy is.
There’s dust everywhere, and no matter how many stars you have to vacuum up that dust,
it just still keeps coming.
Reminds me of my house and be sure to check out my books at your favorite online book
retailer and subscribe to my channels for regular in-depth explorations into the interesting,
weird and unknown aspects of this amazing universe in which we live.