Extra-solar fireballs??

[JohnD]

Today, 13th June, the Space Weather site features the NASAAll-Sky Fireball Network: http://spaceweather.com/
It shows a graphic of the calculated orbits of objects that have penetrated the Earth's atmosphere and burned up.
Some (coded red & Yellow) are obviously heliocentric.
The really fast ones (blue & Green) appear to have 'fallen' straight down to Earth from extrasolar space.

Now, either the Earth attracts extrasolar objects, or there is a hail of them falling throuhg the Solaar System. that we don't see until they collide with us. Oumuamua was billed as the first observed extrasolar object, so are these apparantly extrasolar origins due to weaknesses in obseervation and calculation?

John

[Chris Peterson]

Today, 13th June, the Space Weather site features the NASAAll-Sky Fireball Network: http://spaceweather.com/
It shows a graphic of the calculated orbits of objects that have penetrated the Earth's atmosphere and burned up.
Some (coded red & Yellow) are obviously heliocentric.
The really fast ones (blue & Green) appear to have 'fallen' straight down to Earth from extrasolar space.

Now, either the Earth attracts extrasolar objects, or there is a hail of them falling throuhg the Solaar System. that we don't see until they collide with us. Oumuamua was billed as the first observed extrasolar object, so are these apparantly extrasolar origins due to weaknesses in obseervation and calculation?

Millions of meteors have had their orbits calculated. To date, none have had definitively hyperbolic orbits, meaning all have parent bodies that were in closed solar orbits. No obviously extrasolar meteors have been observed.

[JohnD]

Thanks, Chris. So their apparent extrasolar origins due to inadequate data.
John

[Chris Peterson]

Thanks, Chris. So their apparent extrasolar origins due to inadequate data.

No, there is a rich, accurate dataset. What is it that makes you think there are apparent extrasolar origins? The color coded speed range extends from the slowest possible meteors (Earth's escape velocity, 11 km/s), to the fastest possible meteors from solar-bound objects (72 km/s). None of the meteors are observed moving faster than 72 km/s, which means they are all in solar orbit.

[neufer]

So their apparent extrasolar origins due to inadequate data.

No, there is a rich, accurate dataset. What is it that makes you think there are apparent extrasolar origins? The color coded speed range extends from the slowest possible meteors (Earth's escape velocity, 11 km/s), to the fastest possible meteors from solar-bound objects (72 km/s). None of the meteors are observed moving faster than 72 km/s, which means they are all in solar orbit.

The fastest possible meteors coming from head on solar-bound objects
is indeed ~72 km/s ~ sqrt[{30[sqrt(2)+1]}²+{11}²].

However, an extra-solar object can hit the Earth from behind to produce a fireball
as slow as ~17 km/s ~ sqrt[{30[sqrt(2)-1]}²+{11}²].

(Note: if this ~17 km/s extra-solar object misses the Earth it would continue off into interstellar
space much as the 16.26 km/s New Horizons was able to do with a minimal assist from Jupiter.)

Hence, the fact that no meteors are observed moving faster than 72 km/s,
is a minimum requirement that they are all in solar orbit.

[Chris Peterson]

So their apparent extrasolar origins due to inadequate data.

No, there is a rich, accurate dataset. What is it that makes you think there are apparent extrasolar origins? The color coded speed range extends from the slowest possible meteors (Earth's escape velocity, 11 km/s), to the fastest possible meteors from solar-bound objects (72 km/s). None of the meteors are observed moving faster than 72 km/s, which means they are all in solar orbit.

The fastest possible meteors coming from head on solar-bound objects
is indeed ~72 km/s ~ sqrt[{30[sqrt(2)+1]}²+{11}²].

However, an extra-solar object can hit the Earth from behind to produce a fireball
as slow as ~17 km/s ~ sqrt[{30[sqrt(2)-1]}²+{11}²].

Hence, the fact that no meteors are observed moving faster than 72 km/s,
is a minimum requirement that they are all in solar orbit.

Note, however, that while the color coding reflects just the v_inf speed, all of these meteors have orbital elements derived. The observation that no extrasolar meteors have been detected is based on the orbit (in particular, the eccentricity), not the collision speed with Earth. (I was addressing John's apparent concern with the highest speed meteors in the diagrams.)

[JohnD]

Thanks, Chris. So their apparent extrasolar origins due to inadequate data.

No, there is a rich, accurate dataset. What is it that makes you think there are apparent extrasolar origins? The color coded speed range extends from the slowest possible meteors (Earth's escape velocity, 11 km/s), to the fastest possible meteors from solar-bound objects (72 km/s). None of the meteors are observed moving faster than 72 km/s, which means they are all in solar orbit.

Can't repost the graphic here, but you may be able to find it in SpaceWeather. The slow objects are shown to have solar orbits, but the fast ones are shown as if coming straight in, from our of the planetary plane, and in straight lines. That's what made me ask, extrasolar??

[Chris Peterson]

Thanks, Chris. So their apparent extrasolar origins due to inadequate data.

No, there is a rich, accurate dataset. What is it that makes you think there are apparent extrasolar origins? The color coded speed range extends from the slowest possible meteors (Earth's escape velocity, 11 km/s), to the fastest possible meteors from solar-bound objects (72 km/s). None of the meteors are observed moving faster than 72 km/s, which means they are all in solar orbit.

Can't repost the graphic here, but you may be able to find it in SpaceWeather. The slow objects are shown to have solar orbits, but the fast ones are shown as if coming straight in, from our of the planetary plane, and in straight lines. That's what made me ask, extrasolar??

No, they are not shown coming straight in. The graphic only displays the Solar System out to between Jupiter and Saturn. You can see the asteroidal meteors because the entire orbit is visible, with aphelions between Mars and Jupiter. But material from cometary origins often has very high eccentricities, and therefore high speeds when passing through the inner system. These fast meteors may look like they're traveling in nearly straight lines simply because we're zoomed in too close to see the full orbits, which may have an aphelions beyond Pluto- many meters off the center of your computer monitor.

[JohnD]

Appreciating the size of astronomical matters often leads one astray.
Thank you, Chris!

John