Author Topic: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)  (Read 35407 times)

Offline Mongo62

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #300 on: 12/21/2017 02:34 AM »
Ejection of material --"Jurads" -- from post main sequence planetary systems

We show that the rate of pollution of white dwarfs by asteroidal material implies a concomitant rate of material ejection that can contribute significantly to the population of interstellar minor bodies. We note also that the irradiation during post main sequence evolution implies that much of this ejected material may lose volatiles, providing a rationale for the curious properties of the recently discovered interstellar object Oumuamua.

Offline Ben the Space Brit

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #301 on: 12/21/2017 08:56 AM »
Did I read that right? Basically, this suggestion is that Oumanuamua is basically a tiny solid bit of a planetary nebulae that has zipped by, aeons after being blown out of its home system by the dissolution of its primary?
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Offline vapour_nudge

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Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #302 on: 12/21/2017 09:33 AM »
I think that there has been a lot of unsupported speculation on this thread. What do we know for a fact about this object?

1. Definitely interstellar in origin, moving at close to the general velocity of gravitationally unbound objects in this part of the Galaxy.

2. There has been no obvious originating exoplanetary system found so far. There are a few possibilities, but all of them appear to have a low probability of being the originating system.

3. The reddish color slope of the object is consistent with an outer solar system object, either asteroidal or cometary. Its color is consistent with a variety of compositions, and in fact is exactly what would be expected for a dormant comet nucleus.

4. The shape derived from its light curve is highly unusual (but not unheard of) for a rocky asteroidal object, but comet nuclei have been found to frequently be quite elongated, although not as elongated as this object appears to be. A small sample size warning for comet nuclei, though.

5. Part of the light curve variations might be due to compositional differences, bringing its shape into the normal range.

6. Its rotation period of around 8 hours is not unusual, and is well over the limit for "rubble piles" of its size.

Conclusion: what we know of this object is consistent with a natural origin in the outer portions of an unidentified exoplanetary system.

Great post which is back to facts. I suspect the feelings of some are: "we can't prove it is not an alien created/manipulated object so it just might be".

It's hard to argue the point with those who just "want" to believe that stuff. We can't prove it isn't a giant dog - or a 1000x scale Tesla Roadster for that matter - but seeing the concise facts posted is great

I read an article recently and can't find it but it suggests the size is possibly a bit over 6:1 ratio now. Initial data suggested 10:1. It's great to see how the data is being refined. We live in exciting times; we don't need alien talk to make it exciting

Offline Star One

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #303 on: 12/21/2017 11:07 AM »
I think that there has been a lot of unsupported speculation on this thread. What do we know for a fact about this object?

1. Definitely interstellar in origin, moving at close to the general velocity of gravitationally unbound objects in this part of the Galaxy.

2. There has been no obvious originating exoplanetary system found so far. There are a few possibilities, but all of them appear to have a low probability of being the originating system.

3. The reddish color slope of the object is consistent with an outer solar system object, either asteroidal or cometary. Its color is consistent with a variety of compositions, and in fact is exactly what would be expected for a dormant comet nucleus.

4. The shape derived from its light curve is highly unusual (but not unheard of) for a rocky asteroidal object, but comet nuclei have been found to frequently be quite elongated, although not as elongated as this object appears to be. A small sample size warning for comet nuclei, though.

5. Part of the light curve variations might be due to compositional differences, bringing its shape into the normal range.

6. Its rotation period of around 8 hours is not unusual, and is well over the limit for "rubble piles" of its size.

Conclusion: what we know of this object is consistent with a natural origin in the outer portions of an unidentified exoplanetary system.

Great post which is back to facts. I suspect the feelings of some are: "we can't prove it is not an alien created/manipulated object so it just might be".

It's hard to argue the point with those who just "want" to believe that stuff. We can't prove it isn't a giant dog - or a 1000x scale Tesla Roadster for that matter - but seeing the concise facts posted is great

I read an article recently and can't find it but it suggests the size is possibly a bit over 6:1 ratio now. Initial data suggested 10:1. It's great to see how the data is being refined. We live in exciting times; we don't need alien talk to make it exciting

Talk about making unrealistic comparisons to try and prove an argument. All that does it make your argument look weak and you’re not going to convince anyone that way.

Offline Mongo62

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #304 on: 12/21/2017 02:41 PM »
Did I read that right? Basically, this suggestion is that Oumanuamua is basically a tiny solid bit of a planetary nebulae that has zipped by, aeons after being blown out of its home system by the dissolution of its primary?

The paper basically states that just as considerable asteroidal / cometary material is being regularly accreted by white dwarfs, other asteroidal / cometary material must be ejected, possibly comprising a significant fraction of all small interstellar objects.

Such material would have been baked by the preceding red giant phase for several million years, resulting in the sort of composition we see with 'Oumuamua.
« Last Edit: 12/21/2017 02:43 PM by Mongo62 »

Offline Mongo62

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #305 on: 12/22/2017 01:05 AM »
Prospects for Backtracing 1I/`Oumuamua and Future Interstellar Objects

1I/`Oumuamua is the first of likely many small bodies of extrasolar origin to be found in the solar system. These interstellar objects (ISOs) are hypothesized to have formed in extrasolar planetary systems prior to being ejected into interstellar space and subsequently arriving at the solar system. This paper discusses necessary considerations for tracing ISOs back to their parent stars via trajectory analysis, and places approximate limits on doing so. Results indicate the capability to backtrace ISOs beyond the immediate solar neighborhood is presently constrained by the quality of stellar astrometry, a factor poised for significant improvement with upcoming Gaia data releases. Nonetheless, prospects for linking 1I or any other ISO to their respective parent star appear unfavorable on an individual basis due to gravitational scattering from random stellar encounters which limit traceability to the past few tens of millions of years. These results, however, do not preclude the possibility of occasional success, particularly after considering the potential for observational bias favoring the discovery of younger ISOs, together with the anticipated rise in the ISO discovery rate under forthcoming surveys.

Offline Mongo62

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #306 on: 01/10/2018 12:50 AM »
1I/2017 'Oumuamua-like Interstellar Asteroids as Possible Messengers from the Dead Stars

Discovery of the first interstellar asteroid (ISA) - 1I/2017 'Oumuamua - raised a number of questions regarding its origin. Many of them relate to its lack of cometary activity, suggesting refractory composition of 'Oumuamua. Here we explore the possibility that 'Oumuamua-like ISAs are produced in tidal disruption events (TDEs) of refractory planetoids (asteroids, dwarf planets, etc.) by the white dwarfs (WDs). This idea is supported by existing spectroscopic observations of metal-polluted WDs, hinting at predominantly volatile-poor composition of accreted material. We show that such TDEs sourced by realistic planetary systems (including a population of >1000 km planetoids and massive perturbers - Neptune-to-Saturn mass planets) can eject to interstellar space up to 30% of planetary mass involved in them. Collisional fragmentation, caused by convergent vertical motion of the disrupted planetoid's debris inside the Roche sphere of the WD, channels most of the original mass into 0.1-1 km fragments, similar to 'Oumuamua. Such size spectrum of ISAs (very different from the top-heavy distributions expected in other scenarios) implies that every WD needs to eject ~0.3M_E of refractory material through TDEs (for ISA albedo of 0.2). This figure is consistent with the existing observations of WD metal pollution once we account for observational biases by using realistic models of circum-WD planetary systems. ISAs should exhibit kinematic characteristics similar to old, dynamically hot Galactic populations; we interpret 'Oumuamua's slow Galactic motion as a statistical fluctuation. ISA ejection in individual planetary TDEs is highly anisotropic, resulting in large fluctuations of their space density. We also show that other ISA production mechanisms involving stellar remnants - direct ejection by massive planets around WDs and SN explosions - have difficulty explaining 'Oumuamua-like ISAs.

Interstellar Interlopers: Number Density and Origins of 'Oumuamua-like Objects

We provide a calculation of Pan-STARRS' ability to detect objects similar to the interstellar object 1I/2017 U1 (hereafter 'Oumuamua), including the most detectable approach vectors and the effect of object size on detection efficiency. Using our updated detection cross-section, we infer an interstellar number density of such objects (nIS≈0.2 au−3). This translates to a mass density of ρIS≈4M⊕ pc−3 which cannot be populated unless every star is contributing. We find that given current models, such a number density cannot arise from the ejection of inner solar system material during planet formation. We note that a stellar system's Oort cloud will be released after a star's main sequence life time and may provide enough material to obtain the observed density. The challenge is that Oort cloud bodies are icy and \OBJECT was observed to be dry which necessitates a crust generation mechanism.

Offline hop

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #307 on: 01/10/2018 02:08 AM »
Breakthrough Listen Observations of Breakthrough Listen with the GBT (typo in original , they meant 'Oumuamua :o)

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We have conducted a search for radio emission consistent with an artificial source targeting 1I/'Oumuamua with the Robert C. Byrd Green Bank Telescope (GBT) between 1.1 and 11.6 GHz. We searched the data for narrow band signals and found none. Given the close proximity to this interstellar object, we can place limits to putative transmitters with extremely low power (0.08 W).
« Last Edit: 01/10/2018 02:09 AM by hop »

Offline Star One

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #308 on: 01/19/2018 08:38 PM »
Update on an Interstellar Asteroid

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What’s the news coming from the research world on the interstellar asteroid visitor, asteroid 1I/’Oumuamua? Read on for an update from a few of the latest studies.

http://aasnova.org/2018/01/19/update-on-an-interstellar-asteroid/

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