Tracking the interstellar object 'Oumuamua to its home
A team of astronomers led by Coryn Bailer-Jones of the Max Planck Institute for Astronomy has tracked the interstellar object 'Oumuamua to several possible home stars. The object was discovered in late 2017 – this was the first time astronomers have been able to observe an astronomical object from another star system visiting our own Solar System. Bailer-Jones and his colleagues used data from the ESA astrometry satellite Gaia to find four plausible stars where 'Oumuamua could have begun its long journey, more than a million years ago. [...] Earlier studies had attempted similar reconstructions of 'Oumuamua's origin, but had not come up with plausible candidates.
These earlier studies were missing a crucial ingredient: in June 2018, a group led by ESA astronomer Marco Micheli had shown that 'Oumuamua's orbit within the Solar System is not that of an object in free fall, that is, of an object moving exclusively under the influence of gravity. Instead, there was some additional acceleration when the object was close to the Sun. The likely explanation is that 'Oumuamua has some similarity to a comet – with ice that, when sufficiently heated by sunlight, produces gas that will in turn accelerate the source object like an exceedingly weak rocket engine. Although weak - the outgassing was not visible on images like it is with comets close to the Sun - it is too large to be ignored when back-tracking the orbit. The new study by Bailer-Jones and colleagues takes into account how 'Oumuamua's orbit has changed as the object passed close to the Sun, giving the astronomers a precise estimate of the direction the object came from originally, as well as the speed at which it entered our Solar System.
[...] Bailer-Jones and his colleagues found four stars that are possible candidates for 'Oumuamua's home world. All four of them are dwarf stars. The one that came closest to 'Oumuamua, at least about one million year ago, is the reddish dwarf star HIP 3757. It approached within about 1.96 light-years. Given the uncertainties unaccounted for in this reconstruction, that is close enough for 'Oumuamua to have originated from its planetary system (if the star has one). However, the comparatively large relative speed (around 25 km/s) makes it less probable for this to be 'Oumuamua's home. The next candidate, HD 292249, is similar to our Sun, was a little bit less close to the object's trajectory 3.8 million years ago, but with a smaller relative speed of 10 km/s. The two additional candidates met 'Oumuamua 1.1 and 6.3 million years ago, respectively, at intermediate speeds and distances. These stars have been previously catalogued by other surveys, but little is known about them.
Also at Space.com.
Plausible home stars of the interstellar object 'Oumuamua found in Gaia DR2
Previously: 'Oumuamua Likely Originated in the Local Association (Pleiades Moving Group)
'Oumuamua Outgasses Like a Comet
Related Stories
The interstellar asteroid 'Oumuamua's likely movements have been tracked based on the relative positions of nearby stars. Observations of 'Oumuamua indicate that it has only been subjected to interstellar conditions (cosmic rays, gas, dust) for hundreds of millions of years rather than billions. There are likely to be around 46 million such interstellar objects entering the solar system every year, most of which are too far away to be seen with current telescopes, and are quickly ejected:
[My (Fabo Feng)] latest study gives us a glimpse of exactly where 'Oumuamua may have come from. Reconstructing the object's motion, my research suggests it probably came from the nearby "Pleiades moving group" of young stars, also known as the "Local Association". It was likely ejected from its home solar system and sent out to travel interstellar space.
Based on 'Oumuamua's trajectory, I simulated how it has probably travelled through the galaxy and compared this to the motions of nearby stars. I found the object passed 109 stars within a distance of 16 light years. It went by five of these stars from in the Local Association (a group of young stars likely to have formed together), at a very slow speed relative to their movement.
It's likely that when 'Oumuamua was first ejected into space, it was travelling at just enough speed to break away from the gravity of its planet or star of origin, rather than at a much faster speed that would require even more energy. This means we'd expect the object to move relatively slowly at the start of its interstellar journey, and so its slow encounters with these five stars suggests it was ejected from one of the group.
Pleiades star cluster. "Code and results" for the arXiv paper.
We should capture as many interstellar asteroids as possible and smash them together to create a new dwarf planet near the Earth.
Previously: Possible Interstellar Asteroid/Comet Enters Solar System
Interstellar Asteroid Named: Oumuamua
ESO Observations Show First Interstellar Asteroid is Like Nothing Seen Before
Breakthrough Listen to Observe Interstellar Asteroid 'Oumuamua for Radio Emissions (none were found)
The interstellar space rock that mystified astronomers is actually a comet
A mysterious space rock, first spotted in 2017, bewildered astronomers — was it an icy comet, a rocky asteroid, or something entirely new? As the object, called 'Oumuamua, hurtles away from us, the mystery may be solved: it's accelerating like a comet.
Researchers tracked the space rock's trajectory on its way out of this solar system, using telescopes on the ground and the powerful Hubble Space Telescope to keep watch even as the interstellar visitor faded out of [sight]. They discovered that 'Oumuamua's speed couldn't just be the result of gravity. It was accelerating — which could be explained by gas puffing out of the sun-warmed end of a comet, the team reports today in the journal Nature [DOI: 10.1038/s41586-018-0254-4] [DX].
Also at ESA and ESA/Hubble.
Previously: Interstellar Asteroid Named: Oumuamua
ESO Observations Show First Interstellar Asteroid is Like Nothing Seen Before
Oumuamua Likely Originated in the Local Association (Pleiades Moving Group)
Latest on ʻOumuamua at CNN:
(CNN)The first observed interstellar object zipped through our solar system in October 2017 -- and astronomers have been trying to understand it ever since.
Scientists scrambled to observe the object before it disappeared, moving along at 196,000 miles per hour, and their observations caused more questions than answers about the "oddball," as scientists dubbed it.
Now, the latest research suggests it is a fragment of a Pluto-like planet from another solar system.Steven Desch and Alan Jackson, two astrophysicists at Arizona State University's School of Earth and Space Exploration, have studied observations made of the unusual features of 'Oumuamua. Their findings published Tuesday in two studies in the American Geophysical Union Journal of Geophysical Research: Planets.
Nitrogen Ice, seems to be the answer. But, not conclusive.
Theories that 'Oumuamua is an alien object or piece of technology have circulated since the object appeared, and it's the basis for the new book "Extraterrestrial: The First Sign of Intelligent Life Beyond Earth" by Avi Loeb, a professor of science at Harvard University.
There is no evidence to prove that 'Oumuamua is alien technology, the researchers for this study said, although it's natural that the first observed object from outside of our solar system would bring aliens to mind.
"But it's important in science not to jump to conclusions," Desch said. "It took two or three years to figure out a natural explanation — a chunk of nitrogen ice — that matches everything we know about 'Oumuamua. That's not that long in science, and far too soon to say we had exhausted all natural explanations."
Not saying it was Aliens, but, not saying it was aliens.
(Score: 0, Funny) by Anonymous Coward on Wednesday September 26 2018, @05:34AM
...the outgassing is too large to be ignored.
(Score: 2) by richtopia on Wednesday September 26 2018, @05:36AM
http://starshiptroopers.wikia.com/wiki/Bug_Meteor [wikia.com]
(Score: 3, Interesting) by KritonK on Wednesday September 26 2018, @07:22AM (2 children)
One million years from now, the astronomers of some other solar system will track 'Oumuamua's orbit back to our solar system, claiming incorrectly that it originated here. What makes us think that the object originated in one of those four solar systems, just because it came from their direction?
(Score: 1, Funny) by Anonymous Coward on Wednesday September 26 2018, @07:45AM (1 child)
http://www.mpia.de/homes/calj/gdr2_oumuamua/oumuamua_gdr2.pdf [www.mpia.de]
(Score: 2) by KritonK on Thursday September 27 2018, @06:55AM
From the abstract:
So, most likely, it didn't originate there.
(Score: -1, Troll) by MyOpinion on Thursday September 27 2018, @10:10PM
How is an interstellar asteroid "being tracked"?
NASA admits they do not track Hubble, and ESA is tracking an interstellar asteroid? How?
Is it because "it is relatively close"?
Where does this data about this "interstellar asteroid" come from?
Truth is like a Lion: you need not defend it; let it loose, and it defends itself. https://discord.gg/3FScNwc