Vega. Are Sol and Vega destined to collide?

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Discussion Overview

The discussion revolves around the potential future interaction between the stars Sol and Vega, specifically whether they are on a collision course. Participants explore the implications of Vega's radial velocity measurements, proper motion, and the nature of stellar interactions over astronomical timescales.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant notes that Vega's radial velocity measurements indicate it is blue-shifted, suggesting it is moving towards Sol at an average speed of about 9.0875 miles per second, which could imply a close approach in 518,000 years.
  • Another participant counters that Vega's proper motion is approximately 350 milli-arc seconds per year, indicating it is moving sideways relative to the Sun and thus poses no collision risk.
  • It is mentioned that even during galaxy collisions, the probability of stars colliding is extremely low.
  • A participant highlights that having a component of movement towards Sol does not necessarily mean Vega is on a collision course, as it would require a transverse component of zero, which is unlikely.
  • One participant expresses concern that even a close pass by Vega could disrupt the solar system, potentially moving Earth out of the habitable zone.

Areas of Agreement / Disagreement

Participants express differing views on the likelihood of a collision between Sol and Vega. While some argue that Vega's movement indicates a potential close approach, others assert that its proper motion and the nature of stellar interactions suggest no collision risk exists.

Contextual Notes

The discussion includes various assumptions about stellar motion and the implications of proximity, but these assumptions are not universally accepted among participants.

twistedspark
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Am I misunderstanding the measurements or what? The SIMBAD site has archived 17 measurements or Vega's radial velocity over the past 150 years and they are all negative (blue-shifted) averaging out to about 9.0875 miles per second. Since Vega is only 25.29 lightyears away this seems to indicate that Vega and our star will be right on top of one another in 518,000 years. A very short time on a planetary scale. Not even as long as mammals have been dominant on Earth.
Granted that's not an immediate concern, but if that was true I'm pretty certain I would have heard about it by now. I haven't heard anything about this anywhere. I just came to this apparent conclusion from bits and pieces I've read and watched while learning about stellar masses, types, etc.
It would also seem to me that you can't ascribe our movement towards Vega our planetary orbit of the Sun nor Vega around a companion star. Vega is solitary, and is almost perfectly aligned with our North pole and we with one of it's poles.
Also, Vega is expected to survive as a main sequence star for another 500 million years, so if it's on a collision course it will be here long before it becomes a red giant.

Sources:

http://simbad.u-strasbg.fr/simbad/s...ubmit=display+selected+measurements#lab_meas"

http://en.wikipedia.org/wiki/Vega"

http://www.solstation.com/stars/vega.htm"
 
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It's proper motion is about 350 milli-arc seconds per year, which means it's moving sideways with respect to the Sun. Thus not a collision risk.
 
even when entire galaxies collide, the chances of any stars hitting other stars is extremely close to zero.
 
As graal points out, just because it has a component of movement towards us does not mean it's on a collision course. In order for it to be on a collision course, it would have to also have a transverse component of zero, which would be a fabulously small probability (for any set of objects that are moving toward us).
 
OK, thanks. Where do you find the info on it's transverse motion?
I of course realize the stars wouldn't actually "collide," but having a star as massive as Vega pass too close would probably rip our solar system apart, and in the very least purterb the system enough to move the Earth out of the 'goldilocks zone.'
 

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