'Oumuamua one year later

October 22, 2018, Harvard-Smithsonian Center for Astrophysics
'Oumuamua one year later
An artist's rendering of 'Oumuamua, a visitor from outside the solar system. Astronomers used the IRAC camera on the Spitzer Space Telescope to set a limit on the infrared emission from 'Oumuamua and thus to estimate its size. Credit: Joy Pollard / Gemini Observatory / AURA / NSF

One year ago this week astronomers discovered an unusual object moving through space not too far from the Earth's orbit. In just a few days they realized it could not be a normal asteroid or comet – its path showed that it was not gravitationally bound to the solar system. It was, therefore, the first interstellar body ever discovered in our solar system that originated from outside it. It was given the Hawaiian name 'Oumuamua, "scout."

Astronomers have long thought that comets and asteroids exist in other planetary systems – perhaps 'Oumuamua came from one of them. Most current models of our own solar system suggest that such small bodies are leftovers from the era of planet formation, and other should also have produced comets and asteroids. Studying them would offer powerful insights into the similarities and differences in planetary system formation. So far, however, it has been impossible: the presumed large populations of comets and asteroids found in exoplanetary circumstellar disks are far away and their individual members are faint and spatially unresolved.

'Oumuamua might therefore be a rare scientific resource, and it became the subject of an intense, though brief, observing campaign—brief because it was so fast moving that it quickly became too distant and faint to detect. Nevertheless, the observations that were completed found that it was reddish in color, with no apparent spectral features and no signs of gas or dust. All these suggest it might be something like a primitive ("D-type") asteroid, although in truth there is no good analog known in our solar system. Most remarkable of all, as it rotated its variable light curve revealed that it has a very elongated shape: six times longer than it is wide.

The IRAC camera on the Spitzer Space Telescope is currently about 155 million miles from Earth, and had a very different viewing angle toward 'Oumuamua than did Earth-bound telescopes. CfA astronomers Joe Hora, Howard Smith and Giovanni Fazio, together with their long-standing team of Near Earth Object scientists and other colleagues, pointed IRAC at the spot in the sky where predictions placed 'Oumuamua (because it is not bound to the solar and is so fast moving, 'Oumuamua's path in the sky was comparatively difficult to calculate).

After 30 hours of staring – a relatively long time – the object was not detected, and subsequent orbital analyses confirmed that the camera was pointed correctly toward it. The limit to its emission, however, was so low that it enabled the team to constrain some of its physical properties. The lack of an infrared signal, for example, suggests it has no gas or dust, species that would be expected if it were a cometary-like body. The scientists also calculate that, depending on its exact composition and reflectivity, 'Oumuamua is at least 240 meters (and maybe as much as one kilometer) in its longest dimension (for Star Trek aficionados, some fans estimate the length of the Enterprise to be 725 meters). The object has now moved too far for any of our telescopes to see it, and so although it will remain an interstellar mystery, it reminds us yet again that our cosmic neighborhood is full of surprises.

Explore further: 'Oumuamua likely came from a binary star system

More information: Spitzer Observations of Interstellar Object 1I/'Oumuamua, Astrophysical Journal (in press) 2018

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Osiris1
2 / 5 (4) Oct 23, 2018
It is a ship, a star ship, and probably a REALLY old derelict one. Crew long dead or maybe they abandoned it. GOD preserve the souls of any of those who died aboard her.

So after all this time it comes out..NObody has really imaged it, but it HAS been measured, roughly, to a little bigger tban an UFP Enterprise on Star Trek.
So my gut feeling of it is as good, no less, as anyone or anything else's! So it is good to state that idea first for those that only read the first phrase of posts.
It is not moving all that fast as objects go, so we may get another chance to check it out when we have cheaper access to space and have deep-space detector arrays, really large ones. If the measurements tend then to favor it being a ship, an expedition could be in order as the technology potential would make it impossible to ignore and possibilties limitless.
MRBlizzard
1 / 5 (3) Oct 23, 2018
Run silent. Listen hard.
Somebody did fire up an engine; it's undergoing acceleration.
It's leaving in a non-Newtonian hyperbolic orbit.
chaman
2 / 5 (4) Oct 24, 2018
It could be a camouflaged probe with embedded sensors operating in passive mode—hence undetectable. The data thus collected could be transmitted only if the probe is being properly interrogated, presumably far beyond our range of detection. In such a fashion, any technological species that the probe might detect would not know that it has been detected. As we do not know for sure what kind of object it is —neither asteroid not comet apparently — Oumauamua's passage in our neighborhood raises the question: have we been detected?
chaman
5 / 5 (1) Oct 24, 2018
"neither asteroid nor comet apparently" as reported by Ramin Skibba in Quanta Magazine on 10/10/2018, "Interstellar Visitor Found to Be Unlike a Comet or an Asteroid".
rrwillsj
3.5 / 5 (4) Oct 24, 2018
Geez! Getta grip, boys! Put down those stupid comicbiiks and learn how to read real books.

Occam's Razor flushes away all your fallacious fantasies as used toilet paper.

If any of you had actually had any experience with working rock? Hah! Any work experience aside from bagging groceries?

Oumuamua is cosmic debris. The remanent core from an ancient collision of middling-mass asteroids.

Then worn to it's present surface features from countless centuries of abrasive interstellar dust and fragments.

The technical term is the originating rock nodule was knapped.

As for the "acceleration"? Don't they teach you kids elementary, classic science anymore in those church schools?

A random orbit had Oumuamua playing "snap-the-whip" with Sol. Sorry no boogey-man mystery for you to cower from. Just plain old common sense.

Ahh, who am I kidding? The previous comments are proof-positive of how "un-common" is the hard-work of reason and rational.
barakn
4.2 / 5 (5) Oct 25, 2018
As for the "acceleration"? Don't they teach you kids elementary, classic science anymore in those church schools?

A random orbit had Oumuamua playing "snap-the-whip" with Sol. Sorry no boogey-man mystery for you to cower from. Just plain old common sense.

"Our high-precision measurements of 'Oumuamua's position revealed that there was something affecting its motion other than the gravitational forces of the Sun and planets," said Marco Micheli.... "This additional subtle force on 'Oumuamua likely is caused by jets of gaseous material expelled from its surface," said Farnocchia. The team estimates that 'Oumuamua's outgassing may have produced a very small amount of dust particles -- enough to give the object a little kick in speed, but not enough to be detected. https://www.jpl.n...ure=7173
Maybe if you spent less time listening to how awesome you sound as you write...
rrwillsj
4 / 5 (2) Oct 25, 2018
barakan, you might re-read your posting. "Likely", "estimates" "may have" with not a shred of proof. And are contradictory to "but not enough to be detected." Is that what you call "evidence"?

In addition to the researchers conflicting statements of undetected gas jets and undetected dust particles being ejected from our interstellar tourist.

As long as we are all guessing and speculating, how about this?

That as Oumuamua passed Sol, our Sun gave it a smack on the butt with a CME event? Could there have been a Coronal Mass Ejection during that passage? Small enough to escape detection and only energetic enough to impart a very slight acceleration to the rock?

Was there any observation of the voyager that could confirm or deny that it the propelling energy was CME particles and/or gases or dust expelled from the asteroid?

Cause, yeah... I'm awesome! Still producing the best quality of hypothesis to be found in these comments.
jonesdave
2.3 / 5 (3) Oct 25, 2018
Could there have been a Coronal Mass Ejection during that passage? Small enough to escape detection and only energetic enough to impart a very slight acceleration to the rock?


With the greatest of respect - no.

rrwillsj
3.5 / 5 (2) Oct 25, 2018
damn jd, that's a downer!

factual reality is chivvying me to drink! Yeah. that's gonna be my excuse....

{I still think I did the bestest guesstimate grumble, grumble}
JaxPavan
3 / 5 (2) Nov 07, 2018
The odd thing about oumuamua is that it did a "NASA style" gravity-assist (nearly optimal 60 degrees angle of approach in relation to the sun's relative direction of motion which optimizes the velocity boost of the gravity-assist "slingshot").

A deliberate gravity-assist would also approach as close as it could to the sun, which it arguably did.

but it also popped back up through the planetary orbital planes right at the orbital distance of an interesting blue planet covered in water, and timed it just as it was orbiting by.

That is one smart, curious asteroid.

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