Author Topic: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)  (Read 72656 times)

Offline alang

  • Full Member
  • **
  • Posts: 247
  • Liked: 96
  • Likes Given: 6
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #60 on: 10/29/2017 07:23 PM »
:) Not too seriously.

The object's trajectory in and out of the Solar system follows the flight path of a  covert system survey mission as describe in some of the more esoteric Sci-Fi literature.

But, perhaps they build in threes :-)

Offline hop

  • Senior Member
  • *****
  • Posts: 3339
  • Liked: 472
  • Likes Given: 826
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #61 on: 10/29/2017 08:37 PM »
how does one (basically) interpret the direction the object came from?  The galactic plane is different from the solar system orbital plane.  I just hit the limit of Google fu.
You can plug the RA/DEC from https://projectpluto.com/temp/2017u1.htm into any planetarium software, star chart site etc. However... which stars appear in that direction now does not tell you anything about possible sources, you have to account for the stars motion. Stars move a lot on tens of thousands of years timescales.

The animation on https://twitter.com/tony873004/status/924343154660098048 gives a good idea how much this matters.

People have work on this stuff have already looked and found it's not obviously traceable back to any local star, see comments from Mamajek upthread.
« Last Edit: 10/29/2017 08:38 PM by hop »

Offline Phil Stooke

  • Full Member
  • ****
  • Posts: 484
  • Canada
  • Liked: 299
  • Likes Given: 0
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #62 on: 10/29/2017 08:50 PM »
"how does one (basically) interpret the direction the object came from?  The galactic plane is different from the solar system orbital plane. "


https://web.njit.edu/~gary/321/Lecture18.html

This website has math for it, but it also has a nice chart showing both RA/DEC coordinates and galactic coordinates.  A bit of a mess, but you can plot a position in RA/DEC and figure out where that is relative to the galactic equator and poles.  This could be superimposed over a map of constellations if you like. 

« Last Edit: 10/29/2017 08:51 PM by Phil Stooke »

Offline KelvinZero

  • Senior Member
  • *****
  • Posts: 3806
  • Liked: 603
  • Likes Given: 158
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #63 on: 10/29/2017 11:03 PM »
In practice, there's another problem though: It will be invisible to our biggest telescopes very soon, and the uncertainties on the trajectory would make it very, very hard to find years down the road.
Having a really accurate trajectory would be fun.. I wonder how far back in time we could extrapolate it's journey.

Online Mongo62

  • Full Member
  • ****
  • Posts: 969
  • Liked: 612
  • Likes Given: 137
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #64 on: 10/30/2017 12:14 AM »
Palomar Optical Spectrum of Hyperbolic Near-Earth Object A/2017 U1

We present optical spectroscopy of the recently discovered hyperbolic near-Earth object A/2017 U1, taken on 25 Oct 2017 at Palomar Observatory. Although our data are at a very low signal-to-noise, they indicate a very red surface at optical wavelengths without significant absorption features.


Offline sanman

  • Senior Member
  • *****
  • Posts: 4444
  • Liked: 672
  • Likes Given: 8
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #65 on: 10/30/2017 01:13 AM »
Palomar Optical Spectrum of Hyperbolic Near-Earth Object A/2017 U1

We present optical spectroscopy of the recently discovered hyperbolic near-Earth object A/2017 U1, taken on 25 Oct 2017 at Palomar Observatory. Although our data are at a very low signal-to-noise, they indicate a very red surface at optical wavelengths without significant absorption features.

What does that red likely indicate? Iron Oxide? Other possibilities?

Offline Dalhousie

  • Senior Member
  • *****
  • Posts: 2188
  • Liked: 313
  • Likes Given: 385
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #66 on: 10/30/2017 01:26 AM »
Palomar Optical Spectrum of Hyperbolic Near-Earth Object A/2017 U1

We present optical spectroscopy of the recently discovered hyperbolic near-Earth object A/2017 U1, taken on 25 Oct 2017 at Palomar Observatory. Although our data are at a very low signal-to-noise, they indicate a very red surface at optical wavelengths without significant absorption features.

What does that red likely indicate? Iron Oxide? Other possibilities?

I would guess Tholins
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Offline KelvinZero

  • Senior Member
  • *****
  • Posts: 3806
  • Liked: 603
  • Likes Given: 158

Offline Ben the Space Brit

  • Senior Member
  • *****
  • Posts: 7140
  • A spaceflight fan
  • London, UK
  • Liked: 662
  • Likes Given: 771
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #68 on: 10/30/2017 09:50 AM »
As I understand it, A/2017 U1 is moving at about 26km/s relative to the solar system which is (or so I am led to understand) about the average velocity spread between the Sun and other nearby stars (~30km/s, to be specific).

How much can we infer from this? Does this mean that the object is a member of the family of objects born in the same molecular cloud as The Sun? Does that also mean that we should expect a co-moving group of stars should also have a 'corona' of ejected objects moving in between them?
"Oops! I left the silly thing in reverse!" - Duck Dodgers

~*~*~*~

The Space Shuttle Program - 1981-2011

The time for words has passed; The time has come to put up or shut up!
DON'T PROPAGANDISE, FLY!!!

Offline hop

  • Senior Member
  • *****
  • Posts: 3339
  • Liked: 472
  • Likes Given: 826
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #69 on: 10/30/2017 04:35 PM »
How much can we infer from this? Does this mean that the object is a member of the family of objects born in the same molecular cloud as The Sun?
No, the opposite. The Sun's birth cluster dispersed long ago. A/2017 U1 has the same sort of velocity as random field stars, so its potential origins diverse as they are.  As Bynaus pointed out
Regarding orgins, there is a simple short-hand to estimate travel distances: for each km/s at infinity, the object will travel about a parsec per million years. So for this one, 25 parsecs (~82 light years) per million year. Even if it travelled only a few million years, it could have come from very far away!

Does that also mean that we should expect a co-moving group of stars should also have a 'corona' of ejected objects moving in between them?
We already pretty much knew this would be the case: We've seen quite a few solar system objects become slightly hyperbolic through interactions with planets, and have very good reason to believe the same happens elsewhere. There was a lot of uncertainty about how common such objects are, and A/2017 U1 may help answer that.

Offline hop

  • Senior Member
  • *****
  • Posts: 3339
  • Liked: 472
  • Likes Given: 826
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #70 on: 10/30/2017 04:42 PM »
Karen Meech and collaborators recieved HST DDT for this object
Which way home? Finding the origin of our Solar System's first interstellar visitor

Quote
We request HST/WFC3/UVIS observations of A/2017 U1, a recently discovered fast moving and fast fading object that appears to originate from outside the Solar System. Rapid follow-up observations from the ground established the object's orbit as hyperbolic and thus ruled out that A/2017 U1 is a comet or asteroid. The proposed observations are critical to (a) determine the object's rotation period in order to allow observations to be performed at maximal brightness, and (b) obtain precise astrometry along an extended arc length in order to identify the region from which this object originated.

A/2017 U1 is the first known interloper from outside the Solar System, and the observations proposed here play a pivotal role in determining its origin.
« Last Edit: 10/30/2017 04:43 PM by hop »

Online jebbo

  • Full Member
  • ****
  • Posts: 641
  • Cambridge, UK
  • Liked: 267
  • Likes Given: 250
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #71 on: 10/30/2017 05:35 PM »
We already pretty much knew this would be the case: We've seen quite a few solar system objects become slightly hyperbolic through interactions with planets, and have very good reason to believe the same happens elsewhere. There was a lot of uncertainty about how common such objects are, and A/2017 U1 may help answer that.

That it is probably rocky is (as you've said above) somewhat surprising. But that does make me wonder if *some* of the slightly hyperbolic objects we've seen before might actually be interstellar visitors ...

Edit: my reasoning might not be clear here: if you assume the majority of ejected material is icy i.e. that this one atypical and that we didn't just get lucky, then some of the e~=1.05 objects being interstellar visitors would make the composition distribution closer to that predicted.

--- Tony
« Last Edit: 10/30/2017 05:39 PM by jebbo »

Offline hop

  • Senior Member
  • *****
  • Posts: 3339
  • Liked: 472
  • Likes Given: 826
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #72 on: 10/30/2017 06:22 PM »
Edit: my reasoning might not be clear here: if you assume the majority of ejected material is icy i.e. that this one atypical and that we didn't just get lucky, then some of the e~=1.05 objects being interstellar visitors would make the composition distribution closer to that predicted.
The Engelhardt paper linked earlier also suggests this is possible
Quote
Some of the synthetic detected ISOs had eccentricities as small as 1.01 --- in the range of the largest eccentricities of several known comets.
One obvious question though is why we haven't seen any faster ones.  e=~1 represents an extreme end of the distribution, so naively if any of our e=~1 comets are interstellar, one would expect to see at least a few which were more obviously hyperbolic. Figure 5 from the above paper attached.

Also notable in this figure, A/2017 U1 fits reasonably well in the asteroid predictions.
« Last Edit: 10/31/2017 11:58 PM by hop »

Offline Bynaus

  • Full Member
  • ****
  • Posts: 522
  • Dreamer, Scientist, Teacher, Writer, Husband & Dad
  • Switzerland
    • Final-Frontier.ch
  • Liked: 365
  • Likes Given: 252
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #73 on: 10/30/2017 06:44 PM »
Well, maybe if the orbit can be determined with enough accuracy (precovery images?), one could still consider to build a nuclear-ion-propelled probe (with a big delta-v reserve) and send it after it. It might take decades to chase it down, but it could well be worth it - as Mamajek writes, we will never get so close to exoplanetary objects anytime soon. Even if we find another one a few decades from now, each of these exoasteroids should be unique as each (in all likelyhood) represents a different exoplanetary system.
More of my thoughts: www.final-frontier.ch (in German)

Online redliox

  • Full Member
  • ****
  • Posts: 1949
  • Arizona USA
  • Liked: 392
  • Likes Given: 64
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #74 on: 10/30/2017 07:17 PM »
I don't supposed a request has been made from the Hubble yet?
"Let the trails lead where they may, I will follow."
-Tigatron

Online Johnnyhinbos

  • Full Member
  • ****
  • Posts: 1390
  • Boston, MA
  • Liked: 1614
  • Likes Given: 222
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #75 on: 10/30/2017 07:29 PM »
I don't supposed a request has been made from the Hubble yet?
I believe if you look a few posts upthread you will see that the request has already been made to HST...
John Hanzl. Author, action / adventure www.johnhanzl.com

Offline missinglink

  • Full Member
  • *
  • Posts: 123
  • Liked: 19
  • Likes Given: 110
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #76 on: 10/30/2017 09:12 PM »
:) Not too seriously.

The object's trajectory in and out of the Solar system follows the flight path of a  covert system survey mission as describe in some of the more esoteric Sci-Fi literature.

I immediately thought of this passage, in Peter Watts' novel Blindsight. This is describing the course change performed by Theseus, the spaceship sent to survey the mysterious aliens who took pictures of Earth and then disappeared:

Quote
She'd taken us a good fifteen AUs towards our destination before something scared her off course. Then she'd skidded north like a startled cat and started climbing: a wild high three-gee burn off the ecliptic, thirteen hundred tonnes of momentum bucking against Newton's First.

Offline Zed_Noir

  • Senior Member
  • *****
  • Posts: 2535
  • Canada
  • Liked: 397
  • Likes Given: 593
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #77 on: 10/30/2017 09:35 PM »
:) Not too seriously.

The object's trajectory in and out of the Solar system follows the flight path of a  covert system survey mission as describe in some of the more esoteric Sci-Fi literature.

I immediately thought of this passage, in Peter Watts' novel Blindsight. This is describing the course change performed by Theseus, the spaceship sent to survey the mysterious aliens who took pictures of Earth and then disappeared:

Quote
She'd taken us a good fifteen AUs towards our destination before something scared her off course. Then she'd skidded north like a startled cat and started climbing: a wild high three-gee burn off the ecliptic, thirteen hundred tonnes of momentum bucking against Newton's First.

Was remembering some passage from the ancient Lensman series novels from E.E. "Doc" Smith  ;)

Online Mongo62

  • Full Member
  • ****
  • Posts: 969
  • Liked: 612
  • Likes Given: 137
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #78 on: 10/31/2017 11:47 PM »
Kinematics of the Interstellar Vagabond A/2017 U1

The initial Galactic velocity vector for the recently discovered hyperbolic asteroid A/2017 U1 is calculated for before its encounter with our solar system. When the velocity is compared to the local stars, A/2017 U1 can be easily ruled out as co-moving with any of the dozen nearest systems, i.e. it does not appear to be associated with any local exo-Oort clouds (most notably that of the Alpha Centauri triple system). The object's velocity is within 5 km/s of the mean Galactic velocity of the stars in the solar neighborhood (<25 pc), so its velocity would appear to be typical for that of a body whose velocity was drawn from the Galactic velocity distribution of the local stars. These calculations strengthen the interpretation that A/2017 U1 has a distant extrasolar origin, but not among the very nearest stars.


Offline Zed_Noir

  • Senior Member
  • *****
  • Posts: 2535
  • Canada
  • Liked: 397
  • Likes Given: 593
Re: Hyperbolic Hyperbole or Interstellar Interloper?
« Reply #79 on: 11/01/2017 01:10 AM »
@Mongo62
 So we can call A/2017 U1 a "Rogue Dwarf Planet"?  ;D

Tags: