Theoretical closest approach of SWAN to Earth orbit (4Oct06)

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Expand view Topic review: Theoretical closest approach of SWAN to Earth orbit (4Oct06)

by chinajon » Fri Nov 17, 2006 1:46 am

BMAONE23 wrote:
iamlucky13 wrote:

Also, I'm a little confused about it being found by SOHO. I know SOHO is the most prolific comet finder ever, I think finding hundreds as they swing near enough to the sun to pass into its narrow field of view, but comets generally are very dull after passing close to the sun. In contrast, the APOD caption says it was discovered in June, but just now reached is peaking in brightness. Did it just happen to cross SOHO's field on the far side of the sun from the earth and an AU or so from the sun?
Yes. On or about August 21 it crossed behind the sun, traveling from below the ecliptic to above it, and into SOHO's field of view.
Just a note...
The field of view of one SOHO camera is wide. It can view about 30 times the Sun's diameter. The APOD of 2006 November 16 shows Jupiter, Venus, Mercury and Mars, in one photograph.
;-D

by BMAONE23 » Thu Oct 05, 2006 5:16 pm

iamlucky13 wrote:

Also, I'm a little confused about it being found by SOHO. I know SOHO is the most prolific comet finder ever, I think finding hundreds as they swing near enough to the sun to pass into its narrow field of view, but comets generally are very dull after passing close to the sun. In contrast, the APOD caption says it was discovered in June, but just now reached is peaking in brightness. Did it just happen to cross SOHO's field on the far side of the sun from the earth and an AU or so from the sun?
Yes. On or about August 21 it crossed behind the sun, traveling from below the eccliptic to above it, and into SOHO's field of view.

by iamlucky13 » Thu Oct 05, 2006 3:59 pm

That's definitely in the realm of current possibilities.

I see three possibilities. First, the comet originated in the Oort cloud like normal, but the collision or gravitational interaction that caused it to swing through the inner solar system imparted enough energy for it to escape.

Second, Orca's interstellar hot potato theory, where it was cast out from another solar system by a similar interaction. Simply based on the scale of interstellar space and the idea that if it could happen somewhere else it could happen here, too, I think the hot-potato is less likely than the first theory (but fun nonetheless).

Third, comets form not only in the Oort cloud, but also from free hydrogen, oxygen, and dust in interstellar space. It happened to drift around for a while before its path and our solar system's crossed. Naturally, it's trajectory would be affected by the solar system's gravity pulling it inward, but it in the end it still has enough velocity to run straight back out.

Also, I found the link in the caption for hyperbolic discussed a comet in 1976 that originally appeared to be on a hyperbolic trajectory, but in the end they decided that difference between an extremely eccentric elliptical orbit and a hyperbolic trajectory was less than the uncertainty of calculated path.

by FieryIce » Thu Oct 05, 2006 1:01 pm

I checked out that link to NASA's Orbit Simulation, are we to believe that Swan came out of no where, did some interesting trajectory angles, just to loop through Earth's orbital path and keep on going off to no where?

by orin stepanek » Thu Oct 05, 2006 1:08 am

Orca wrote:That's an interesting idea...a rogue comet, flung out of one solar system, travels for hundreds of millions of years...and then happens to "skip off" another star system somewhere else...

Inter-stellar hot potato!

Another thought: scientists say that the examination of comets and other solar system debris will help us understand the early stages of the solar system. What about comets from other solar systems? Will they be indistinguishable? It would be pretty amazing to study an object from another solar system without having to leave our own back yard...
And maybe we could plant a probe on this comet and use it to explore interstellar space. :roll: :!: Just a thought. :)
Orin

by Orca » Wed Oct 04, 2006 9:18 pm

That's an interesting idea...a rogue comet, flung out of one solar system, travels for hundreds of millions of years...and then happens to "skip off" another star system somewhere else...

Inter-stellar hot potato!

Another thought: scientists say that the examination of comets and other solar system debris will help us understand the early stages of the solar system. What about comets from other solar systems? Will they be indistinguishable? It would be pretty amazing to study an object from another solar system without having to leave our own back yard...

by iamlucky13 » Wed Oct 04, 2006 9:08 pm

orin stepanek wrote:http://antwrp.gsfc.nasa.gov/apod/ap061004.html

This comet is hyperbolic. Once it leaves the solar system it will never return as it will go into interstellar space. I'm thinking it is not an Oort cloud comet; and not from our solar system. Probably a vagabond drifting through space? :roll:
Orin
My thoughts, as well. Anybody know if other comets have been found on escape trajectories before this one? It would be very interesting to know that such objects drift about in interstellar space.

Also, I'm a little confused about it being found by SOHO. I know SOHO is the most prolific comet finder ever, I think finding hundreds as they swing near enough to the sun to pass into its narrow field of view, but comets generally are very dull after passing close to the sun. In contrast, the APOD caption says it was discovered in June, but just now reached is peaking in brightness. Did it just happen to cross SOHO's field on the far side of the sun from the earth and an AU or so from the sun?

by Wadsworth » Wed Oct 04, 2006 3:21 pm

orin stepanek wrote:http://antwrp.gsfc.nasa.gov/apod/ap061004.html

This comet is hyperbolic. Once it leaves the solar system it will never return as it will go into interstellar space. I'm thinking it is not an Oort cloud comet; and not from our solar system. Probably a vagabond drifting through space? :roll:
Orin
It would pretty much have to be unless it was an Oort but got flung out of it's ellipse by some other mass.

by orin stepanek » Wed Oct 04, 2006 2:28 pm

http://antwrp.gsfc.nasa.gov/apod/ap061004.html

This comet is hyperbolic. Once it leaves the solar system it will never return as it will go into interstellar space. I'm thinking it is not an Oort cloud comet; and not from our solar system. Probably a vagabond drifting through space? :roll:
Orin

by BMAONE23 » Wed Oct 04, 2006 1:40 pm

http://neo.jpl.nasa.gov/cgi-bin/db?sstr=C%2F2006+M4

According to this link, I would say that your presumed distance of between 0.1 and 0.2 au is accurate.

Theoretical closest approach of SWAN to Earth orbit (4Oct06)

by Blerg » Wed Oct 04, 2006 5:49 am

APOD of 2006-10-04. I followed the link of "Comet SWAN" to the small body database browser
http://ssd.jpl.nasa.gov/sbdb.cgi?ID=dK0 ... ;cov=0#orb. When passing the Earth orbit, our planet seems to be nearly on the opposite side of the sun.
But how close would the comet have been to Earth nearest, i.e. if Earth would have been at that point of its orbit closest to the point where the comet penetrates the orbital plane?
The simulation on the website only shows distances from the comet to the actual earth poisition, so my best guess (deriving from the distance between Earth and Mars orbit) is somewhere between 0,2 and 0,1 AU.
Is anyone here able to calculate how close the comet would have been to Earth if Earth would have been on the "right place"? And how bright would the comet be visible to us?

Thomas.

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