What if hypervelocity star came near Sun?

"Raghar" ha scritto nel messaggio
ups.com...

Ian Stirling wrote:
In sci.space.policy OG wrote:
Neglecting the gravitational effects.
What happens to the interacting solar winds/magnetic fields of the two
stars?

It would be too weak to talk about it

Nothing for the solar winds, only that the limit of heliosphere should
change
from 80 A.U. toward the Sun, until 40, 20, 10 A.U.? For the Earth
it should be not very big problems, the solar wind of Sun deflect
a side of galattic cosmic rays but if the limit of heliosphere it's more of
1.A.U., better 2 A.U. we not should have big problems.
For the magnetic field, yes this can to change the magnetic field of
Sun in the Solar Sistem then the Earth magnetic field should change
dimension and form, perharps we can have more auroras, perharps
until Equator, we should have perturbations in radio link on the surface
of our planet and too with artificial satellites, we should too have
changes in weather and if this accross many years too on vegetation
and then too on animals and naturally on our civilisation.
All this if the "guest" star has 1 solar mass and pass at 80 A.U.
We must remember that all the effects are heavy linked at the
mass of the star, its minimal distance from the Sun, its speed
(then the time of passage), the path of the star and too the type
of star, a little red star it's different from a Wolf-Rayet!
Sao 67174

"Alfred Montestruc" wrote in message
oups.com...
|
| tracy wrote:
| According to this article, the mysterious super-high speed stars are
| more numerous and fastest than previously though. What if one of these
| "hypervelocity" stars came through Sun's neighborhood?
|
| Depends on what is meant by the "Sun's neighborhood".
|
| I suspect that a hypervelocity star could pass the Sun within a
| light-year (very very close on intersteller standards) and have no
| effect at all on the solar system other than provide a good show. It
| could pass close enough to influance an outer gas giant (like say
| Neptune) a lot, and have no effect on earth. As long as the star is
| not also a giant star (say on the order of the same absolute magnitude
| of the sun or smaller) the only effects worth worrying about are
| gravitational.
|
|
| How dangerous
| it could be for life on Earth?
|
|
|
| Hypotetically totally fatal, but not likely. As long as the star does
| not come close enough to disterb the earth's orbit, no significant
| effect. And it could come close enough to disterb one or more gas
| giants a lot and not effect the earth much at all, however the
| secondary fallout of that (lots more comets, or the giant having an
| orbit that comes much closer to the sun) could also be fatal, but not
| likely IMHO.
|
|
|
| What would be safe distance a star moving at about 700 - 1000 km/s
| could get near Sun without disrupting the planetary system?
|
| By assuming a short term (less than one earth year) influance of
| 1/100th the suns pull on an outer gas giant is not going to screw the
| human race over, then 10 (ok 11) times the distance of Neptune to the
| sun should be safe for a hypervelocity star with the same mass as the
| sun, linearly proportional to the mass of the star, more mass, further
| away. It might shift the orbit of one or more outer gas giants a bit,
| but not enough to cause them to cross the orbit of another planet or to
| leave the solar system. Maybe more comets.
|

What is the "influance" that causes example 8 on this web page?
http://faculty.ifmo.ru/butikov/Proje...llection1.html
Is it "hypotetical" influenza?

Sorcerer wrote:
"Alfred Montestruc" wrote in message
oups.com...
|
| tracy wrote:
| According to this article, the mysterious super-high speed stars are
| more numerous and fastest than previously though. What if one of these
| "hypervelocity" stars came through Sun's neighborhood?
|
| Depends on what is meant by the "Sun's neighborhood".
|
| I suspect that a hypervelocity star could pass the Sun within a
| light-year (very very close on intersteller standards) and have no
| effect at all on the solar system other than provide a good show. It
| could pass close enough to influance an outer gas giant (like say
| Neptune) a lot, and have no effect on earth. As long as the star is
| not also a giant star (say on the order of the same absolute magnitude
| of the sun or smaller) the only effects worth worrying about are
| gravitational.
|
|
| How dangerous
| it could be for life on Earth?
|
|
|
| Hypotetically totally fatal, but not likely. As long as the star does
| not come close enough to disterb the earth's orbit, no significant
| effect. And it could come close enough to disterb one or more gas
| giants a lot and not effect the earth much at all, however the
| secondary fallout of that (lots more comets, or the giant having an
| orbit that comes much closer to the sun) could also be fatal, but not
| likely IMHO.
|
|
|
| What would be safe distance a star moving at about 700 - 1000 km/s
| could get near Sun without disrupting the planetary system?
|
| By assuming a short term (less than one earth year) influance of
| 1/100th the suns pull on an outer gas giant is not going to screw the
| human race over, then 10 (ok 11) times the distance of Neptune to the
| sun should be safe for a hypervelocity star with the same mass as the
| sun, linearly proportional to the mass of the star, more mass, further
| away. It might shift the orbit of one or more outer gas giants a bit,
| but not enough to cause them to cross the orbit of another planet or to
| leave the solar system. Maybe more comets.
|

What is the "influance" that causes example 8 on this web page?

;-)

I don't know, though gravity sounds like a possible one, also possilby
computational issues. Depends on how short or long the time steps are,
and how many significant digits the model uses, which the author did
not clearly specify (I did not see any such, if you know where he did
let me know.)


What you seem to miss is that the closest approach of the hyper
velocity star is going to be for a tiny segment of the normal orbit of
the planet. After that time it is gone. This is based on the speed of
the star and the very long orbital periods of the outer planets. In
the example you give, the sattelite is under the pull of both bodies
for 1.5 orbits before I could see any deflection from the previous
orbit at all.

reference web site for data:

http://www.nineplanets.org/data.html

In the case we are discussing the normal orbital period of Neptune is
60190.00 days, and a radius of orbit of 4504300 km (mean), and the
hypervelocity star will travel the radius of Neptunes orbit in
4504300km/700km/sec = 6449 seconds or 1.791 hours, or 0.0746 days.
That translates into 1.24e-6 of the period of the planet, with an
influence maximum of 1/100th the sun's pull. Fat chance that is going
to do much that is noticeable to a stable orbit in that amount of time.
Note that in one day that star will have moved 13.4 times the mean
radisu of Neptune's orbit.

Note that the example you gave are of an UNSTABLE orbit and the guy who
maintains the website says so.
---quote

8. Satellite at the outer collinear libration point. This example
illustrates regular motion of a satellite at the outer collinear
Lagrange point for the case of circular motions. The motion of the
satellite is unstable: soon it leaves this point and orbits irregularly
one of the bodies. (Click also here to see the applet.)

---end quote




Even one day at 1/100 the sun's pull is tiddly winks when set next to
the period of Neptune.


http://faculty.ifmo.ru/butikov/Proje...llection1.html
Is it "hypotetical" influenza?

My carpo tunnel sorry.

wrote in message
oups.com...
|
| Sorcerer wrote:
| "Alfred Montestruc" wrote in message
| oups.com...
| |
| | tracy wrote:
| | According to this article, the mysterious super-high speed stars are
| | more numerous and fastest than previously though. What if one of
these
| | "hypervelocity" stars came through Sun's neighborhood?
| |
| | Depends on what is meant by the "Sun's neighborhood".
| |
| | I suspect that a hypervelocity star could pass the Sun within a
| | light-year (very very close on intersteller standards) and have no
| | effect at all on the solar system other than provide a good show. It
| | could pass close enough to influance an outer gas giant (like say
| | Neptune) a lot, and have no effect on earth. As long as the star is
| | not also a giant star (say on the order of the same absolute magnitude
| | of the sun or smaller) the only effects worth worrying about are
| | gravitational.
| |
| |
| | How dangerous
| | it could be for life on Earth?
| |
| |
| |
| | Hypotetically totally fatal, but not likely. As long as the star does
| | not come close enough to disterb the earth's orbit, no significant
| | effect. And it could come close enough to disterb one or more gas
| | giants a lot and not effect the earth much at all, however the
| | secondary fallout of that (lots more comets, or the giant having an
| | orbit that comes much closer to the sun) could also be fatal, but not
| | likely IMHO.
| |
| |
| |
| | What would be safe distance a star moving at about 700 - 1000 km/s
| | could get near Sun without disrupting the planetary system?
| |
| | By assuming a short term (less than one earth year) influance of
| | 1/100th the suns pull on an outer gas giant is not going to screw the
| | human race over, then 10 (ok 11) times the distance of Neptune to the
| | sun should be safe for a hypervelocity star with the same mass as the
| | sun, linearly proportional to the mass of the star, more mass, further
| | away. It might shift the orbit of one or more outer gas giants a bit,
| | but not enough to cause them to cross the orbit of another planet or
to
| | leave the solar system. Maybe more comets.
| |
|
| What is the "influance" that causes example 8 on this web page?
|
| ;-)
|
| I don't know

Fair enough. You snipped the URL too.

I've returned the compliment by snipping and not bothering to
read what you wrote, ape. :-)

Alfred Montestruc schreef:

snip


What would be safe distance a star moving at about 700 - 1000 km/s
could get near Sun without disrupting the planetary system?

By assuming a short term (less than one earth year) influance of
1/100th the suns pull on an outer gas giant is not going to screw the
human race over, then 10 (ok 11) times the distance of Neptune to the
sun should be safe for a hypervelocity star with the same mass as the
sun, linearly proportional to the mass of the star, more mass, further
away. It might shift the orbit of one or more outer gas giants a bit,
but not enough to cause them to cross the orbit of another planet or to
leave the solar system. Maybe more comets.

What would the effect be of the hypervelocity star passing through the
Oort Cloud? And even if it's not going to influence the orbit of
Neptune, isn't the Kuyper belt just beyond Neptune's orbit?

VGer47

Sorcerer wrote:
wrote in message
-----------------------snip
| What is the "influance" that causes example 8 on this web page?
|
| ;-)
|
| I don't know

Fair enough. You snipped the URL too.

I've returned the compliment by snipping and not bothering to
read what you wrote, ape. :-)

Well guess who is grouchy & humorless prig today, , ,

wrote in message
ps.com...
|
| Sorcerer wrote:
| wrote in message
| -----------------------snip
| | What is the "influance" that causes example 8 on this web page?
| |
| | ;-)
| |
| | I don't know
|
| Fair enough. You snipped the URL too.
|
| I've returned the compliment by snipping and not bothering to
| read what you wrote, ape. :-)
|
| Well guess who is grouchy & humorless prig today, , ,

Err.... ?
Did I guess right?
|

VGer47 wrote:
Alfred Montestruc schreef:

snip


What would be safe distance a star moving at about 700 - 1000 km/s
could get near Sun without disrupting the planetary system?

By assuming a short term (less than one earth year) influance of
1/100th the suns pull on an outer gas giant is not going to screw the
human race over, then 10 (ok 11) times the distance of Neptune to the
sun should be safe for a hypervelocity star with the same mass as the
sun, linearly proportional to the mass of the star, more mass, further
away. It might shift the orbit of one or more outer gas giants a bit,
but not enough to cause them to cross the orbit of another planet or to
leave the solar system. Maybe more comets.

What would the effect be of the hypervelocity star passing through the
Oort Cloud? And even if it's not going to influence the orbit of
Neptune, isn't the Kuyper belt just beyond Neptune's orbit?

Humm, a few Oort Cloud objects get kicked to hell and gone, as in out
of the solar system never to be seen again. A very few might well be
thrown into steep cometary orbits and that might include a planetary
sized body along the size of say Eris or Pluto. Not likely IMHO, but
possible. More likely it is thrown from the solar system.

Anything that passes withing a lot less than an AU of the thing may
have a significant shift in velocity.

Say the closest approach is 1 AU and as I worked out for Sorcerer and
he rudely did not bother to read since he is being a grouch today, the
hypervelocity star will cover the distance from Neptune to the sun in a
small fraction of a day (0.0746 days), Then the acceleration of the
sun's gravity at the orbit of earth is about 0.00594 m/s/s based on it
being 9.81 on the earth's surface and using the proportions given in
the below website and that acceleration of gravity is proportional to
the mass of the object and the square of the distance from it.

gsun@earths orbit=9.81 x (msun/mearth)/(rad earth orbit/rad earth)^2

refer to the below websites for hard numbers.

http://www.nineplanets.org/data.html

http://www.nineplanets.org/data1.html


Then we can with a lot of safety assume that the total acceleration of
the object passed by the hypervelocity star at 1 AU on closest approach
will be less than the total velocity change for 0.00594 m/s for 0.0746
days (6445 seconds).

That delta v is 38 m/s is tiddly winks set next to the earth's orbital
velocity of 29785 m/s.

The change in the earth's orbital path would not be noticeable.
However the change would be more important for an object much further
from the sun.

Note the numbers are assuming the star has the same mass as the sun, if
more the effect is larger if less smaller and about linear with the
mass of the star.

Sorcerer wrote:
wrote in message
ps.com...
|
| Sorcerer wrote:
| wrote in message
| -----------------------snip
| | What is the "influance" that causes example 8 on this web page?
| |
| | ;-)
| |
| | I don't know
|
| Fair enough. You snipped the URL too.
|
| I've returned the compliment by snipping and not bothering to
| read what you wrote, ape. :-)
|
| Well guess who is grouchy & humorless prig today, , ,

Err.... ?
Did I guess right?

Try again three guesses and if you can't get it you owe me a beer, the
above counts as one.

wrote in message
ups.com...
|
| Sorcerer wrote:
| wrote in message
| ps.com...
| |
| | Sorcerer wrote:
| | wrote in message
| | -----------------------snip
| | | What is the "influance" that causes example 8 on this web page?
| | |
| | | ;-)
| | |
| | | I don't know
| |
| | Fair enough. You snipped the URL too.
| |
| | I've returned the compliment by snipping and not bothering to
| | read what you wrote, ape. :-)
| |
| | Well guess who is grouchy & humorless prig today, , ,
|
| Err.... ?
| Did I guess right?
|
| Try again three guesses and if you can't get it you owe me a beer, the
| above counts as one.

Err.... ?