Interstellar Interlopers, Coming in from the great beyond |
Interstellar Interlopers, Coming in from the great beyond |
Sep 25 2019, 05:53 PM
Post
#166
|
|
Merciless Robot Group: Admin Posts: 8785 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Yeah, that exceedingly low relative velocity was really the only compelling piece of evidence to me. It does not seem unreasonable to postulate that this body had been at one time loosely (and distantly) associated with Kruger 60 and then perturbed out of the neighborhood & towards the Solar System perhaps just from other distant stellar encounters.
However, that also leaves open the possibility that Kruger 60 was not its system of genesis; might've been a semi-captured drifter there from someplace else. In any case, fascinating. Looking forward to some good spectral data. -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
|
|
|
Sep 26 2019, 01:41 AM
Post
#167
|
|
Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
Our system is about 1/3 the age of the universe. Earlier in the age of the universe, heavy elements were nonexistent, then accumulated gradually. So the rate of production of new stars with comets should be, on balance, increasing, though star formation can ebb and flow in ways unique to any given galaxy.
The number of unknowns, though, is profound. We can say that a double system allows a dynamic for easy ejection although a large planet makes that possible as well. |
|
|
Sep 26 2019, 05:45 AM
Post
#168
|
|
Member Group: Members Posts: 716 Joined: 3-January 08 Member No.: 3995 |
|
|
|
Sep 26 2019, 08:39 AM
Post
#169
|
|
Member Group: Members Posts: 214 Joined: 30-December 05 Member No.: 628 |
Nice! Where would Kruger 60 be on those maps?
|
|
|
Sep 26 2019, 09:53 AM
Post
#170
|
|
Senior Member Group: Members Posts: 3516 Joined: 4-November 05 From: North Wales Member No.: 542 |
Great plots Gladstoner, thanks for posting. The first one shows nicely how the comet's path is being deflected by its solar encounter. Look for the antipodal point of its approach path, close to Beta Centauri. That's the direction it was heading before we got in the way.
|
|
|
Sep 26 2019, 02:04 PM
Post
#171
|
|
Senior Member Group: Members Posts: 4256 Joined: 17-January 05 Member No.: 152 |
|
|
|
Sep 27 2019, 11:14 AM
Post
#172
|
|
Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
Some of you may find this site useful for tracking Borisov. I use this for observing comets. Unfortunately, Borisov is a lot dimmer than the comets I have successfully observed, but perhaps we'll get lucky and it will get much brighter in December. It is certainly a wildcard as to how it may behave when it approaches perihelion.
https://theskylive.com/c2019q4-info |
|
|
Oct 13 2019, 02:42 AM
Post
#173
|
|
Member Group: Members Posts: 214 Joined: 30-December 05 Member No.: 628 |
https://www.space.com/mysterious-comet-inte...er-borisov.html
This article refers to a paper by Polish researchers who seem pretty certain that Kreuger 60 is the system of origin. |
|
|
Apr 13 2020, 07:12 PM
Post
#174
|
|
Member Group: Members Posts: 684 Joined: 24-July 15 Member No.: 7619 |
New Paper on how tidal effects can stretch Interstellar comets.
Image: A ‘Oumuamua-like object produced by a simulation of the tidal disruption scenario proposed by Zhang and Lin. Credit: NAOC/Y. Zhang; background: ESO/M. Kornmesser. https://www.centauri-dreams.org/2020/04/13/...o-for-oumuamua/ |
|
|
Apr 14 2020, 05:58 PM
Post
#175
|
|
Junior Member Group: Members Posts: 28 Joined: 17-April 08 From: Okemos, MI, USA Member No.: 4097 |
tidal effects can stretch Interstellar comets. Isn't the key difficulty that the object was rotating somewhat rapidly in a stretched configuration? This requires cohesiveness in the stretched geometry that seems inconsistent with a tidally stretched rubble pile. The description here (https://www.hou.usra.edu/meetings/apophis2020/pdf/2018.pdf) indicates that they think it can melt and then freeze in an elongate configuration, but although that seems possible, there must be a very narrow window where that would occur rather than disruption or reconsolidation into a ball. I can't seem to find the paper online, but I did find an unrelated but extremely cool thesis using the same software tool that works out the Brazil nut effect for asteroid regolith: https://www.astro.umd.edu/people/Theses/2017Ballouz.pdf |
|
|
Apr 22 2020, 06:09 PM
Post
#176
|
|
Senior Member Group: Members Posts: 4256 Joined: 17-January 05 Member No.: 152 |
The Zhang and Lin paper was posted on the arxiv here.
|
|
|
Apr 26 2020, 06:47 AM
Post
#177
|
|
Merciless Robot Group: Admin Posts: 8785 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
I was surprised to see this considering it's now a couple of years old. Looks like a small object in a retrograde 1:1 orbital resonance with Jupiter may be of extrasolar origin, and the same may be true of some Centaurs.
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
|
|
|
Apr 27 2020, 03:12 AM
Post
#178
|
|
Member Group: Members Posts: 214 Joined: 30-December 05 Member No.: 628 |
I can't find the reference via Google so I am short on details, but I recall several years ago there was a proposal for a retrograde head-on flyby of multiple asteroids in the main belt. It could not have gotten very far, but maybe a trajectory of that sort could be adapted to closely inspect this object at aphelion. I guess the power requirements would be in Juno's class though, so it would not be cheap.
|
|
|
Apr 27 2020, 06:11 AM
Post
#179
|
|
Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
I'll offer the caveat that this is not my field in any but an amateur sense, but the publication was accepted only three days after it was received, and, per the journal's own description, a "letter" constitutes a very light form of peer review wherein speed is favored over rigor.
That's an observation from a process point of view, but from the scientific, I'm very skeptical that simulations running back >4 billion years could speak unambiguously to the origins of an object. And I would opine that this is why the work was published only on a fast track two years ago without the world flocking to this as an exceptional result in the meantime. |
|
|
Apr 27 2020, 01:52 PM
Post
#180
|
|
Senior Member Group: Members Posts: 1592 Joined: 14-October 05 From: Vermont Member No.: 530 |
That's an observation from a process point of view, but from the scientific, I'm very skeptical that simulations running back >4 billion years could speak unambiguously to the origins of an object. And I would opine that this is why the work was published only on a fast track two years ago without the world flocking to this as an exceptional result in the meantime. I know a lot less that you, I wager, but I was thinking that this was a bit of: 1. "there are no explanations for local origin that we cannot discount (this work)" 2. ... 3. "a 1:1 retrograde orbital resonance with Jupiter." |
|
|
Lo-Fi Version | Time is now: 24th September 2024 - 12:03 AM |
RULES AND GUIDELINES Please read the Forum Rules and Guidelines before posting. IMAGE COPYRIGHT |
OPINIONS AND MODERATION Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators. |
SUPPORT THE FORUM Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member. |