Author Topic: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)  (Read 62327 times)

Offline jebbo

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Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #260 on: 11/27/2017 06:54 AM »
A short paper discussing possible origins for `Oumuamua.

It makes a reasonable argument for a young age and has a less extreme aspect ratio of 6:1.

Quote
With a hyperbolic trajectory around the Sun, `Oumuamua is the first confirmed interstellar object. However, its origin is poorly known. By simulating the orbits of 0.23 million local stars, we find 109 encounters with periastron less than 5 pc. `Oumuamua's low peculiar velocity is suggestive of its origin from a young stellar association with similar velocity. In particular, we find that `Oumuamua would have had slow encounters with at least five young stars belonging to the Local Association thus suggesting these as plausible sites for formation and ejection. In addition to an extremely elongated shape, the available observational data for `Oumuamua indicates a red colour suggestive of a potentially organic-rich and activity-free surface. These characteristics seem consistent with formation through energetic collisions between planets and debris objects in the middle part of a young stellar system. We estimate an abundance of about 6.0×10−3 au−3 for such interstellar objects with mean diameter larger than 100 m and find that it is likely that most of them will be ejected into the Galactic halo. Our Bayesian analysis of the available light curves indicates a rotation period of 6.96+1.45−0.39 h which is consistent with the estimation by Meech et al. 2017 and shorter than other literature. The codes and results are available on GitHub.

https://arxiv.org/abs/1711.08800

--- Tony
It's not aliens. It's never aliens.

Offline Star One

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Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #261 on: 11/27/2017 12:09 PM »
A short paper discussing possible origins for `Oumuamua.

It makes a reasonable argument for a young age and has a less extreme aspect ratio of 6:1.

Quote
With a hyperbolic trajectory around the Sun, `Oumuamua is the first confirmed interstellar object. However, its origin is poorly known. By simulating the orbits of 0.23 million local stars, we find 109 encounters with periastron less than 5 pc. `Oumuamua's low peculiar velocity is suggestive of its origin from a young stellar association with similar velocity. In particular, we find that `Oumuamua would have had slow encounters with at least five young stars belonging to the Local Association thus suggesting these as plausible sites for formation and ejection. In addition to an extremely elongated shape, the available observational data for `Oumuamua indicates a red colour suggestive of a potentially organic-rich and activity-free surface. These characteristics seem consistent with formation through energetic collisions between planets and debris objects in the middle part of a young stellar system. We estimate an abundance of about 6.0×10−3 au−3 for such interstellar objects with mean diameter larger than 100 m and find that it is likely that most of them will be ejected into the Galactic halo. Our Bayesian analysis of the available light curves indicates a rotation period of 6.96+1.45−0.39 h which is consistent with the estimation by Meech et al. 2017 and shorter than other literature. The codes and results are available on GitHub.

https://arxiv.org/abs/1711.08800

--- Tony
It's not aliens. It's never aliens.

It’s never aliens until it is.

Offline RotoSequence

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Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #262 on: 11/27/2017 12:16 PM »
It’s never aliens until it is.

One day, but probably not today.
« Last Edit: 11/27/2017 12:17 PM by RotoSequence »

Offline Star One

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Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #263 on: 11/27/2017 12:18 PM »
It’s never aliens until it is.

One day, but probably not today.

Just hope that day is before I kick the bucket.

Offline Johnnyhinbos

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Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #264 on: 11/27/2017 12:43 PM »
It’s never aliens until it is.

One day, but probably not today.

Just hope that day is before I kick the bucket.
(could be one and the same...)
John Hanzl. Author, action / adventure www.johnhanzl.com

Offline Mongo62

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Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #265 on: 11/28/2017 01:40 AM »
A general method for assessing the origin of interstellar small bodies: the case of 1I/2017 U1 (Oumuamua)

With the advent of more and deeper sky surveys, the discovery of interstellar small objects entering into the Solar System has been finally possible. In October 19, 2017, using observations of the PANSTARRS survey, a fast moving object, now officially named 1I/2017 U1 (Oumuamua), was discovered in a heliocentric unbound trajectory suggesting an interstellar origin. Assessing the provenance of interstellar small objects is key for understanding their distribution, spatial density and the processes responsible for their ejection from planetary system. However, their peculiar trajectories place a limit on the number of observations available to determine a precise orbit. As a result, when its position is propagated ∼10^5−10^6 years backward in time, small errors in orbital elements become large uncertainties in position in the interstellar space. In this paper we present a general method for assigning probabilities to nearby stars of being the parent system of an observed interstellar object. We describe the method in detail and apply it for assessing the origin of 1I/2017 U1. A preliminary list of potential progenitors and their corresponding probabilities is provided. In the future, when further information about the object and/or the nearby stars be refined, the probabilities computed with our method can be updated.

Implications of the interstellar object 1I/'Oumuamua for planetary dynamics and planetesimal formation

The first bona-fide interstellar planetesimal -- the ~100 m-sized 1I/'Oumuamua -- was discovered passing through our Solar System on a hyperbolic orbit. This object was likely ejected from a distant star system and provides constraints that on average ~1 Earth mass of planetesimals are ejected per Solar mass of Galactic stars. Using simulations of giant planet dynamics that include rocky and icy planetesimals, we find that this average mass ejection efficiency is consistent with known exoplanet populations if 'Oumuamua was an icy planetesimal in a population dominated (by mass) by similar small bodies. An asteroidal composition is dynamically disfavoured, and would require both high masses for typical asteroid belts and a low ratio by number of icy to rocky planetesimals. Regardless of the composition, it is unlikely that we would have found an object like 'Oumuamua if it samples a broad planetesimal mass function that is dominated by massive objects. Further detections may therefore place strong constraints on predictions for the planetesimal mass function from streaming instability-induced collapse, or point to unexpected collisional or dynamical evolution taking place at large radii in planet-forming discs around young stars.


Offline sanman

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Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #266 on: 11/30/2017 01:56 PM »
Apparently Musk's BFR might be capable of a mission to catch up with the interstellar object:

https://www.scientificamerican.com/article/spacex-rsquo-s-planned-giant-rocket-could-chase-down-interstellar-asteroid/

Offline Mongo62

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Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #267 on: 12/01/2017 01:10 AM »
1I/'Oumuamua is tumbling

The discovery of 1I/2017 U1 ('Oumuamua) has provided the first glimpse of a planetesimal born in another planetary system. This interloper exhibits a variable colour, within a range that is broadly consistent with local small bodies such as the P/D type asteroids, Jupiter Trojans, and dynamically excited Kuiper Belt Objects. 1I/'Oumuamua appears unusually elongated in shape, with an axial ratio exceeding 5:1. Rotation period estimates are inconsistent and varied, with reported values between 6.9 and 8.3 hours. Here we analyse all reliable optical photometry reported to date. No single rotation period can explain the exhibited brightness variations. Rather, 1I/'Oumuamua appears to be in an excited rotational state undergoing Non-Principal Axis (NPA) rotation, or tumbling. A satisfactory solution has apparent lightcurve frequencies of 0.135 and 0.126 hr-1 and implies a longest-to-shortest axis ratio of 5:1, though the available data are insufficient to uniquely constrain the true frequencies and shape. Assuming a body that responds to NPA rotation in a similar manner to Solar System asteroids and comets, the timescale to damp 1I/'Oumuamua's tumbling is at least a billion years. 1I/'Oumuamua was likely set tumbling within its parent planetary system, and will remain tumbling well after it has left ours.

Offline Mongo62

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Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #268 on: 12/04/2017 01:40 AM »
Tumbling motion of 1I/'Oumuamua reveals body's violent past

Models of the Solar System evolution show that almost all the primitive material leftover from the formation of the planets was ejected to the interstellar space as a result of dynamical instabilities. Accordingly, minor bodies should also be ejected from other planetary systems and should be abundant in the interstellar space. The number density of such objects, and prospects for their detection as they penetrate through the Solar System, were speculated about for decades, recently rising high hopes with the Pan-STARRS and LSST surveys. These expectations materialized on 18 October 2017 with the Pan-STARRS's discovery of 1I/'Oumuamua. Here we report homogeneous photometric observations of this body from Gemini North, which densely cover a total of 8 hr over two nights. A combined ultra-deep image of 1I/'Oumuamua shows no signs of cometary activity, confirming the results from earlier, less sensitive searches. Our data also show an enormous range of brightness variations > 2.5 mag, larger than ever observed in the population of Solar System objects, suggesting a very elongated shape of the body. But most significantly, the light curve does not repeat exactly from one rotation cycle to another and its double-peaked periodicity of 7.5483 ± 0.0073 hr from our data is inconsistent with earlier determinations. These are clear signs of a tumbling motion, a remarkable characteristic of 1I/'Oumuamua's rotation, consistent with a catastrophic collision in the distant past. This first example of an impacted minor body of exosolar origin indicates that collisional evolution of minor body populations in other planetary systems is not uncommon.

Offline Ludus

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« Last Edit: 12/04/2017 10:17 PM by gongora »

Offline Mongo62

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #270 on: 12/06/2017 12:54 AM »
1I/`Oumuamua as a Tidal Disruption Fragment From a Binary Star System

1I/`Oumuamua is the first known interstellar small body, probably being only about 100 m in size. Against expectations based on comets, `Oumuamua does not show any activity and has a very elongated figure, and also exhibits undamped rotational tumbling. In contrast, `Oumuamua's trajectory indicates that it was moving with the local stars, as expected from a low-velocity ejection from a relatively nearby system. Here we assume that `Oumuamua is typical of 100-m interstellar objects, and speculate on its origins. We find that giant planets are relatively inefficient at ejecting small bodies from inner solar systems of main-sequence stars, and that binary systems offer a much better opportunity for ejections of non-volatile bodies. We also conclude that `Oumuamua is not a member of a collisional population, which could explain its dramatic difference from small asteroids. We observe that 100 m small bodies are expected to carry little mass in realistic collisional populations, and that occasional events when whole planets are disrupted in catastrophic encounters may dominate interstellar population of 100 m fragments. Unlike the Sun or Jupiter, red dwarf stars are very dense and are capable of thoroughly tidally disrupting terrestrial planets. We conclude that the origin of `Oumuamua as a fragment from a planet that was tidally disrupted and then ejected by a dense member of a binary system could explain its peculiarities.

Offline hop

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #271 on: 12/07/2017 05:08 PM »
Is 1I/2017 U1 really of interstellar origin?

Here we investigate the possibility that the asteroid 1I/2017 U1 actually is a Solar System object, currently expelled from the Solar System by the recent encouter with a Solar System planet. We show that this possibility is extremely unlikeley and that 1I/2017 U1 really is an interstellar object.

This talks about the chances of it passing near the hypothetical Planet 9. Even if it did, how would that explain the 26 km/s of heliocentric boost when the orbital velocities hundreds of AU from the Sun are mere fractions of that.
A research note from Jason Wright does the math to confirm this:
On Distinguishing Interstellar Objects Like 'Oumuamua From Products of Solar System Scattering
Quote
1. Could 'Oumuamua Possibly Be a Solar System Object?

The recent discovery of the apparently interstellar3 asteroid 1I/2017 U1 ('Oumuamua)4 has led to speculation about its origin. (Schneider 2017) explored the possibility that it is a solar system object scattered from a solar system planet and concludes that none of the known planets could be the scatterer, nor could the hypothetical "Planet Nine" proposed by Batygin & Brown (2016). Schneider (2017) concludes that if 'Oumuamua is a solar system object, it must have been scattered by "another, yet unknown planet."

If this were true, then one might search for such a planet in the directions of the incoming trajectory of 'Oumuamua and similar objects discovered in the future. However, the orbital energy of 'Oumuamua is too large to be the result of a single scattering event from any hypothetical solar system object

Online llanitedave

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Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #272 on: 12/10/2017 04:29 PM »
A derelict would be so cool...   However that idea suffers from the same probability problem - what are the odds that it would tumble in just in the exact moment in time that humanity gained the instruments to detect such an object?
Another way to look at it: We know that the average star system in the galaxy should have ejected billions of natural objects. We don't know how many artificial objects the average system produces, but it seems safe to assume it's a significantly lower number. Our own system is estimated to have lost ~ Earth masses worth of natural objects, and has only sent a handful of artificial ones.

For chance encounters with randomly drifting stuff, the odds should overwhelmingly favor rocks.
I don't believe the alien hypothesis at all.. but just to have some fun with this:

If this thing were alien technology then yes, that would imply that it wasn't the first, that hundreds of alien objects tumble though our solar system every year and have been doing so for a billion years. Statistically, it would be >50% of every interstellar object. This race would totally dominate the space between stars in our galaxy, so maybe it is 100%

I picture it more like cells in an organism. They give not the slightest damn about us. They may not even care or think about suns. After all, we don't often think about the molten core beneath our feet.

Watch out, because some of the cells are probably antibodies. Fermi paradox resolved.

I had to make sure my vaccinations were up to date after reading this.
"I've just abducted an alien -- now what?"

Offline Jeff Lerner

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #273 on: 12/10/2017 04:49 PM »
Ok...can't resist....since there's been so much speculation on what the object can be...here's my $0.02..

...superior alien race tosses these objects around the galaxy like a stick for a dog to chase and fetch....object passes through a system, no activity, it moves on to the next system..someone goes after it, object signals back to owners that someone is around who they might want to pay attention to...lol

Offline kch

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Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #274 on: 12/10/2017 05:12 PM »
It’s never aliens until it is.

One day, but probably not today.

Just hope that day is before I kick the bucket.

(could be one and the same...)

Cookbook?  ;)

Offline Star One

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #275 on: 12/11/2017 07:25 PM »
Breakthrough Listen is to scan Oumuamua just to make sure it isn’t an alien spaceship.

Here’s the press release.

Quote
San Francisco – December 11, 2017 – Breakthrough Listen, the global astronomical program searching for evidence of civilizations beyond Earth, announced that it is currently focusing its observational efforts on ‘Oumuamua, the mysterious interloper recently spotted moving rapidly through the solar system.
‘Oumuamua was discovered by the Pan-STARRS project at the University of Hawaii in October 2017, passing Earth at about 85 times the distance to the Moon – a stone’s throw, in astronomical terms. It is the first object discovered in the solar system that appears to originate from another star system. Its high speed – 196,000 mph at its peak – suggests it is not gravitationally bound to the Sun, but will continue its voyage back into interstellar space. It has a highly unusual structure for an asteroid – an elongated cigar shape, hundreds of meters in length but with width and height perhaps only one tenth as long.
Researchers working on long-distance space transportation have previously suggested that a cigar or needle shape is the most likely architecture for an interstellar spacecraft, since this would minimize friction and damage from interstellar gas and dust. While a natural origin is more likely, there is currently no consensus on what that origin might have been, and Breakthrough Listen is well positioned to explore the possibility that ‘Oumuamua could be an artifact.
Listen’s observation campaign will begin on Wednesday, December 13 at 3:00 pm ET. Using the Robert C. Byrd Green Bank Telescope, it will continue to observe ‘Oumuamua across four radio bands, from 1 to 12 GHz. Its first phase of observations will last a total of 10 hours, divided into four “epochs” based on the object’s period of rotation.
‘Oumuamua is now about 2 astronomical units (AU) away, or twice the distance between Earth and the Sun. This is closer by a factor of 50-70 than the most distant human artifact, the Voyager I spacecraft. At this distance, it would take under a minute for the Green Bank instrument to detect an omnidirectional transmitter with the power of a cellphone.
“‘Oumuamua’s presence within our solar system affords Breakthrough Listen an opportunity to reach unprecedented sensitivities to possible artificial transmitters and demonstrate our ability to track nearby, fast-moving objects,” said Listen’s Andrew Siemion, Director of Berkeley SETI Research Center. “Whether this object turns out to be artificial or natural, it’s a great target for Listen.”
Even if no signal or other evidence of extraterrestrial technology is heard, Listen observations will cover portions of the radio spectrum in which the object has not yet been observed, and could provide important information about the possibility of water/ice, or the chemistry of a coma (gaseous envelope), neither of which have yet been identified. Listen has already proved its value for traditional, non-SETI astronomy: in August 2017 it detected several dozen repeating fast radio bursts (FRBs) from a distant dwarf galaxy – for details see www.astronomerstelegram.org/?read=10675.

http://breakthroughinitiatives.org/news/14

Offline sanman

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Offline hop

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Offline Mongo62

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #278 on: 12/13/2017 01:28 AM »
Explaining the elongated shape of 'Oumuamua by the Eikonal abrasion model

The photometry of the minor body with extrasolar origin (1I/2017 U1) 'Oumuamua revealed an unprecedented shape: Meech et al. (2017) reported a shape elongation b/a close to 1/10, which calls for theoretical explanation. Here we show that the abrasion of a primordial asteroid by a huge number of tiny particles ultimately leads to such elongated shape. The model (called the Eikonal equation) predicting this outcome was already suggested in Domokos et al. (2009) to play an important role in the evolution of asteroid shapes.

Ejection of rocky and icy material from binary star systems: Implications for the origin and composition of 1I/`Oumuamua

In single star systems like our own Solar system, comets dominate the mass budget of bodies that are ejected into interstellar space, since they form further away and are less tightly bound. However 1I/`Oumuamua, the first interstellar object detected, appears asteroidal in its spectra and in its lack of detectable activity. We argue that the galactic budget of interstellar objects like 1I/`Oumuamua should be dominated by planetesimal material ejected during planet formation in circumbinary systems, rather than in single star systems or widely separated binaries. We further show that in circumbinary systems, rocky bodies should be ejected in comparable numbers to icy ones. This suggests that a substantial fraction of additional interstellar objects discovered in the future should display an active coma. We find that the rocky population, of which 1I/`Oumuamua seems to be a member, should be predominantly sourced from A-type and late B-star binaries.

Offline JasonAW3

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #279 on: 12/13/2017 03:04 AM »
Scanning for signs of technology:

https://www.theatlantic.com/science/archive/2017/12/yuri-milner-oumuamua-interstellar-asteroid/547985/

Probably wouldn't be a bad idea to point an x-ray telescope at this asteroid.  An IR check could also be useful, primarily to get an idea of stresses from its' tumbling.  Any chance of getting radar images of it, or is it too far out now?
My God!  It's full of universes!

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