How to Deflect an Asteroid

[CraigS]

Originally Posted by higginsdj

My mysterious object - well I have put the results up for publishing. The 'old' camp says the results can be explained by YORP (just). The 'young' camp says YORP can't even come close so look for another mechansim. For me, I have no opinion on either - I'm struggling enough with math and working through the math required for Binary Asteroids. To give you an idea of how far behind I am, I have only just been able to derive;

DsDp = Sqrt(10^(0.4*dm)-1) from dm = 2.5 Log(F/F')

where DsDp = Size ratio, dm is delta magnitude of the eclipse events, F and F' are flux from the Uneclipsed and Eclipsed system.

Trying to get my head around angular momentum now......

Cheers

Hmm;
Cool. I'm really happy that you're discovery is upsetting the theoretical apple cart ! Sounds like fun. Ever since you posted your original query, I've been thinking about it .. haven't come up with anything, but I'm sure the experience of thinking it through will linger with me for some time.
(Thanks for the post, by the way).



I'm pretty sure I have no idea of what your derivation above is all about .. but it seems strangely reminiscent of, and related to, what I just read in the Kepler exoplanets discovery paper, just published. (They're dealing with transit timing variations of the exoplanets eclipsing their stars .. sometimes binary systems, also). Interesting.

Anyway, good luck with the publication, etc.

Cheers

[higginsdj]

Its taking the magnitude flux formula and using it to derive the size ratio of a binary system from the depth of the eclipse events. I already had the formula but I just needed to work out where it came from.

Cheers

[Benno18 (Ben)]

whats Brett Lee doing there though???

[CraigS]

Destruction of an asteroid ?? .. Now this is what I'm talkin' about …

Hubble captures Pictures of asteroid collision !

(Image taken around March 2010 by Hubble).

Phil Plait says ..

What apparently has happened is that two small, previously-undiscovered asteroids collided, impacting with a speed of at least 5 km/sec (and possibly faster).

The larger of the two asteroids making up P/2010 A2, is presently estimated, (post collision), to be 140m across ..

Despite how much this looks like a comet, ground-based observations indicate no gas is present, meaning this was from asteroids colliding, not comets, which have significant amounts of ice which turn to gas near the Sun. The collision energy was high enough to produce a lot of gas if any were present. That clinches this being an asteroid impact.

.. one of the Flora family .. probably themselves, remnants of a previous break-up.

Interestingly, the hubblesite release says:

Although the Hubble images give compelling evidence for an asteroid collision, Jewitt says he still does not have enough information to rule out other explanations for the peculiar object. In one such scenario, a small asteroid's rotation increases from solar radiation and loses mass, forming the comet-like tail.

.. and the 'projectile' (if there was one) ..

Astronomers think a smaller rock, perhaps 10 to 15 feet wide, slammed into the larger one. The pair probably collided at high speed, about 11,000 mph, which smashed and vaporized the small asteroid and stripped material from the larger one. Jewitt estimates that the violent encounter happened in February or March 2009 and was as powerful as the detonation of a small atomic bomb.

and the resultants of the (maybe) collision ..

Sunlight radiation then swept the debris behind the remnant asteroid, forming a comet-like tail. The tail contains enough dust to make a ball 65 feet wide, most of it blown out of the bigger body by the impact-caused explosion.

So, we have a theorised collision (probable) .. and empirical evidence of the trajectory of the resulting ejecta … I would think this observation would lead to a model and reasonable predictions for what would happen if a missile impacted such an object ??

(Food for thought .. )
Cheers

[snas (Stuart)]

Hmmm, there is a chapter on deflecting asteroids in Phil Plait's book "Death From the Skies" (a cool read!) Now I just have to remember what Phil said we could do. Surely along the lines of things that have been suggested here. Although I don't think he mentioned weet bix!
Craig, that asteroid collision is ultra cool!
Stuart

[CraigS]

G'Day Stuart;
Yep. The Max Planck Institute guys published a report on this, (as well), late last year, using the measurements taken by the ESA Rosetta spacecraft, which apparently gave a different viewing geometry of the object.

Their conclusion was even more definitive …

We determined that this was an asteroid a collision, that occurred around February 10, 2009.

They've worked out all sorts of interesting snippets like the particle size distribution, tail shape, etc.

What a unique observation. Wish we could've actually captured the collision !! Now that would've been a one in a zillion, (or even more), capture that one !!

From their report ..

From estimates of the population of the main asteroid belt and an estimated impactor diameter of 6-9 m, we expect roughly one impact of this size every 1.1 Gyr for a 120 m diameter parent body, or approximately one every 12 years somewhere in the asteroid belt.
…

Collisions of this size therefore contribute around 3 x 10⌃7 kg/yr of dust to the zodiacal cloud, which is negligible compared with comets and the total required to maintain a steady state, in agreement with recent models.

Cheers