Gliese 710, our impending nearest neighbour.

[dark_energy]

"Gliese 710, an inconspicuous star in the constellation Ophiuchus, is currently 63 light-years away and approaching at about 14 kilometres per second. From the Hipparcos data, it will pass within about one light-year, one million years from now. Joan Garcia-Sanchez, a doctoral student in Preston's team, identifies Gliese 710 in one of the scientific posters that display Hipparcos results in Venice. Garcia-Sanchez has found evidence that Gliese 710 is today moving more slowly towards the Sun than it was several decades ago. That may mean it is orbiting around another star, so far unidentified. If so, the closest distance to which Gliese 710 will approach may be nearer or farther than in the team's initial estimate."<br /><br />Well, there's something I never knew before. I wonder if it's possible that this red dwarf could be <b>captured</b> by the sun at its nearest distance from it. <div class="Discussion_UserSignature"> </div>

 

[dragon04]

If it gets that close, I wonder if it will spur any planetary formation out in the Oort Cloud.<br /><br />Guess I was born a million years too soon. <img src="/images/icons/frown.gif" /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[rfoshaug]

It'll probably pass quite close to us, causing a lot of our comets (and any comets in orbits around Gliese 710) to be tossed both out of the solar system and in towards us. So a few hundred thousand years later, Earth will be bombarded by a lot of comets and asteroids.<br /> <div class="Discussion_UserSignature"> <p><font color="#ff9900">----------------------------------</font></p><p><font color="#ff9900">My minds have many opinions</font></p> </div>

 

[harmonicaman]

Gliese 710

 

[thalion]

Gliese 710 will be traveling far too fast and too far away for the Sun's gravity to capture it.

 

[mlorrey]

"astronomers do not expect it to "perturb the Solar System's Oort Cloud sufficiently to create a substantial increase in the long-period comet flux at Earth's orbit""

 

[harmonicaman]

<b>Mlorrey -</b><br /><br />Yeah, I read that too; and I think it's an unwarranted assumption (i. e., SWAG). We just don't know enough about the mass and extent of the Oort Cloud to be able to accurately assess the impact of Gliese 710.<br /><br />I've read various estimates for the total mass of the Oort Cloud. They've ranged anywhere from the mass of Earth (equal to about 0.6²⁴ kg or 0.0033% of the Solar System's total mass) to as much as the mass of Jupiter (equal to about 1.90²⁷ kg or 1.3% of the Solar System's total mass)<br /><br />I've also read that the Oort Cloud may extend out a full LY from the Solar System, (at least along the plane of the elliptic).<br /><br />I think we need to learn a lot more before we can make accurate assessments concerning the impact of Gliese 710's impending close approach.

 

[tony873004]

It's unlikely that any of Gliese 710's comets will end up in orbit around the Sun, or the Sun's comets orbiting Gleise 710 after the encounter has passed. The velocity is too high to permit captures.<br /><br />Comets from one star could still invade the planetary region of the other star assuming that its Oort Cloud extends to the distance of the encounter. But Gleise 710 is less massive than the Sun. So its Oort Cloud may be a bit smaller.<br /><br />

 

[tony873004]

I've tried to simulate it, but I couldn't. There's a theory that Sedna may have been captured by the Sun when a low-mass star or brown dwarf made a 200 AU passage. But the theory has this happening when the Sun was still in the star cluster where it was born. Stellar encounters in the cluster were slow. The Sedna theory had the encounter at ~1km/s.<br /><br />Likely stellar encounters nowadays would be in the range of ~20-40 km/s. Slower speeds such as 1km/s are still possible, but the probability goes way down just because it would take a long time for a slow star to approach the Sun from a great distance.<br /><br />I tried simulating faster encounters, varying my passage distance, mass of the intruding star, range of the visitor's Oort cloud. I couldn't get any captures at reasonable velocities.<br /><br />Here's a link to my simulation where I recreate the Sedna simulation performed by astronomers.<br />http://www.orbitsimulator.com/gravity/articles/sedna.html

 

[nexium]

Why can't the Oort cloud extend thoughout the galaxy? Comets several light years from a low mass star, would orbit for a fraction of an orbit/3 orbits at most, typically very eliptical then switch to an unstable orbit around a different star etc. Such comets may number a million times a billion 10^15 in our galaxy. Neil

 

[alokmohan]

Forget not we dont know much beyond KBOs.Nature of oort cloud is theoritical