# asteroid 2009 KK: Risk in May,Jun 2009

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#### clmason

##### Guest
Re: asteroid 2009 KK May 29 2022

Thanks MichiganMan, that makes things much clearer!

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#### MeteorWayne

##### Guest
Re: asteroid 2009 KK May 29 2022

Thanx, Michigan Man, it's been a long time since I saw that chart.
So the probability would have to get well above 10e-03 to reach TS2 for a 1.1e03 energy.

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#### clmason

##### Guest
Re: asteroid 2009 KK May 29 2022

So, if I understand it correctly, at roughly 10^-3 we'd hit level 2, and at 10^-2, we'd hit level 4 based on the size of 0.26 km.

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#### MichiganMan

##### Guest
Re: asteroid 2009 KK May 29 2022

clmason":149l90qo said:
So, if I understand it correctly, at roughly 10^-3 we'd hit level 2, and at 10^-2, we'd hit level 4 based on the size of 0.26 km.

Yessir, that's right.

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#### MeteorWayne

##### Guest
Re: asteroid 2009 KK May 29 2022

Technically it's based on the energy, not the size, since the energy is also impacted by impact velocity.

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#### MichiganMan

##### Guest
Re: asteroid 2009 KK May 29 2022

MeteorWayne":rkxl4n9e said:
Technically it's based on the energy, not the size, since the energy is also impacted by impact velocity.

Very true. And speed actually matters more.

Furthermore, speed can be accurately predicted, whereas size is really just an educated guess using apparent magnitude.

...which assumes contant albedo...which is a big assumption, if you ask me.

Consider a dove and a raven both spotted at a distance.... is the dove several times larger because it is "brighter"?

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#### ginyoc

##### Guest
Re: asteroid 2009 KK May 29 2022

Yeah, but to estimate the energy you also have to determine the mass of the body which is just as tricky (if not trickier because you need a size, shape and density estimation :!: ).

Wonder how they do this in the real world. Just with the light reflected and the knowledge how the asteroids are generally composed?

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#### MeteorWayne

##### Guest
Re: asteroid 2009 KK May 29 2022

That's actually discussed in some detail in that Palermo scale article. It turns out, in most cases the density and albedo counteract each other to some extent so the mass is a better estimate than I first thought, within a factor of around 2 or so. Of course the velocity is known with much more precision, and it is the dominant term (being squared, while the mass is halved) in the KE calculation.

MW

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#### ginyoc

##### Guest
Re: asteroid 2009 KK May 29 2022

Haha, thx MW. I'll finally take the time to read the whole article. (btw, the mass being halved has nothing to do with it, for you can apply the factor on the velocity as well, but of course the latter being squared makes it more important)

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#### MeteorWayne

##### Guest
Re: asteroid 2009 KK May 29 2022

What I meant was since the formula is (1/2mass) x V^2, a difference of a factor of 2 in the mass (which is not well known) is not as important as the velocity (which is known to much better than a tenth of a kps) in determining the overall energy. So that part of the equation can now be considered fixed.

Just went and checked, the Vimpact has been 19.14 km/sec since the arc extended to 3 days, so looks like it won't change after this significantly. BTW, this is about the median V impact (V inf= 15.55 kps)

For comparison 2007 VK184 (The other TS1) V impact=19.19 kps, V inf=15.63
Apophis; V impact=12.59, V inf=5.87 km/sec
MW

Edit; more checking. The fastest on the current list:
2005 EL70 V impact=37.21 kps, V inf= 35.5 kps

Slowest:
2008 HU4 V imp=11.18 kps (close to the minumum possible), V inf=0.93 kps

The maximum possible V impact for a highly elliptical retrograde orbit is about 72 kps, such as an object like comet Tempel-Tuttle, parent of the Leonids.

That means for the same mass, an object like Tempel-Tuttle would have 14 times the impact energy of 2009 KK or 2007 VK 184, and 41 times the energy of 2008 HU4.

For a typical object, the energy of 2009 KK would be twice that of Apophis. That might not be true in this case since the current estimated mass of Apophis is based on actual measurements, and is therefore not "estimated".

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#### MichiganMan

##### Guest
Re: asteroid 2009 KK May 29 2022

Zoinks!

with today's data, if no more observations were made, 2009 KK will rise to Palermo Scale +1.08 one year from potential impact...

coincidentally, it crosses the Palermo Scale = 0 threshold at 1.08 years from event.... weird.

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#### ginyoc

##### Guest
Re: asteroid 2009 KK May 29 2022

Er...what I meant is that the factor 1/2 is insignificant. You can write it as you please:
1/2 * (m v²)
m/2 * v²
m * v²/2
So a factor of 2 can still double or halve the energy.
But I guess I'm kind of nitpicking here...

Yippeh.. with the current orbit data 2009KK will rise above the background risk one year before the impact. But as the Palermo scale indicates - chances are we get hit by another object before... :twisted:

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#### MeteorWayne

##### Guest
Re: asteroid 2009 KK May 29 2022

3 more observation, extending the arc to 20 days.

CA in 2022 has increased from .1844 to .1921 AU
Distance on 5/29/2022 increased from .2149 to .2243 AU
RMS residuals decreased slightly to .44125
EMOID increased slightly to 0.00062945 AU (JPL)

So it appears the risk will decrease with these observations.

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##### Guest
Re: asteroid 2009 KK May 29 2022

MeteorWayne":1ophv481 said:
So it appears the risk will decrease with these observations.
I feel vindicated. Do I get a cheese sammich? :lol:

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#### MeteorWayne

##### Guest
Re: asteroid 2009 KK May 29 2022

NEODyS PS is -1.12

Probability 1.11e-04

JPL Data:

# obs. used (total) 98
data-arc span 20 days
first obs. used 2009-05-17
last obs. used 2009-06-06
planetary ephem. DE405
SB-pert. ephem. SB405-CPV-2
quality code 7
fit RMS .44125
data source ORB
producer Otto Matic
solution date 2009-Jun-09 00:50:02

Additional Information Earth MOID = .00062945 AU
T_jup = 4.364

e .4568576181877421 0.00094826
a 1.505836818912769 0.0021617 AU
q .8178837964448753 0.00025408 AU
i 18.27879815549855 0.032865 deg
node 68.20448314339956 0.022056 deg
peri 247.2393319511881 0.0022679 deg
M 337.8788044584721 0.061254 deg
tp 2455041.973566938841
(2009-Jul-29.47356694) 0.025548 JED
period 674.9401979632645
1.85 1.4533
0.003979 d
yr
n .5333805885119233 0.0011485 deg/d
Q 2.193789841380664 0.0031493 AU

NEODyS data:
a 1.50584 0.002195 AU
e 0.456858 0.000963
i 18.279 0.03337 deg
Ω 68.204 0.0224 deg
ω 247.239 0.002304 deg
M 337.879 0.0622 deg
Perihelion 0.8179 AU
Aphelion 2.1938 AU
Orbital period 674.94 days
EMOID 0.00062934

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#### MeteorWayne

##### Guest
Re: asteroid 2009 KK May 29 2022

MeteorWayne":1meitfbm said:
So it appears the risk will decrease with these observations.
I feel vindicated. Do I get a cheese sammich? :lol:

Not yet; it's a very slight decrease (only .02 PS for NEODyS) from -1.10 to -1.12.

There's not a fat lady singing yet...in fact I think she's eating your cheese sammich

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#### silylene

##### Guest
Re: asteroid 2009 KK May 29 2022

The last six observations have come from ARI, the observatory in Charleston, Illinois which has 24" to 48" scopes. Here is the ARI webpage, which is decorated with a couple of frightening graphics (below): http://ari.home.mchsi.com/the_projects.htm , and a couple of nice animations of recently observed objects here: http://ari.home.mchsi.com/neo_followup_project.htm

Finally, a useful definition from the above website:
Potentially Hazardous Asteroids (PHAs) are currently defined based on parameters that measure the asteroid's potential to make threatening close approaches to the Earth. Specifically, all asteroids with an Earth Minimum Orbit Intersection Distance (MOID) of 0.05 AU or less and an absolute magnitude (H) of 22.0 or less are considered PHAs. In other words, asteroids that can't get any closer to the Earth (i.e. MOID) than 0.05 AU (roughly 7,480,000 km or 4,650,000 mi) or are smaller than about 150 m (500 ft) in diameter (i.e. H = 22.0 with assumed albedo of 13%) are not considered PHAs.

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#### MeteorWayne

##### Guest
Re: asteroid 2009 KK May 29 2022

Just to explain the terminology..

V inf is the relative speed between the asteroid and the earth before it enters the earth's gravitational field.

V impact is the speed it will impact the atmosphere after the acceleration due to earth's gravity is added.

After silylene's post, just wante to point out that almost a third of the observations of the asteroid have come from the Charleston, Ill observatory.

MW

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#### sajohnson

##### Guest
Re: asteroid 2009 KK May 29 2022

ginyoc":3mw7lv7c said:
Yippeh.. with the current orbit data 2009KK will rise above the background risk one year before the impact. But as the Palermo scale indicates - chances are we get hit by another object before... :twisted:

I am new here. I found this thread researching the 2009 KK asteroid and I have been trying to learn about the Palermo scale, which I understand is not for the general public. However, I have looked on NASA's NEO site and cannot find any Palermo scale numbers higher than this one. How could we get hit by another object before?

Also, how long do you think observations will be possible until it is no longer visible? I know the TS will likely go back to 0 with increased observations. How long does this usually take?

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#### sajohnson

##### Guest
Re: asteroid 2009 KK May 29 2022

I think I answered my own question... how's this: since the Palermo scale is still negative, that means the asteroid is 10 times less likely to hit us our cause a problem than the background risk (which is average every conditions). Is this right? So as long as it is below 0, then it's less likely to hit than something else on a regular day????

I would still appreciate an answer to my 2nd question about the number of observations

Thank you for your patience with a newbie. I am trying to become more science-literate....

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#### cyclonebuster

##### Guest
Re: asteroid 2009 KK May 29 2022

Why does it matter what the mass is in order to get its velocity? We should be able to get its velocity at any mass.
Mass should be used in order to get impact effects and effects of the solar wind and photon pressure upon the object.

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#### ginyoc

##### Guest
Re: asteroid 2009 KK May 29 2022

Hallo sajohnson!

Yep, you pretty much answered your first question (nevertheless the Palermo Scale is based on a model of the background risk, and models can be proven to be wrong -- so the actual risk compared to the bg risk may be higher or smaller... who knows)

Sorry, can't be of much help regarding your second question. Somewhere in this thread it is mentioned that 2009 KK won't be able to be observed during some time this summer. As I'm pretty new to NEO data as well I don't really know how much time it usually takes until the TS "goes back to 0" but I'm not sure if one could name a time interval there. Could happen that this one stays at 1 a while, which doesn't mean it's going to hit the earth.

@cyclonebuster: The mass is not necessary to estimate the velocity of the object. However to estimate its energy (and therefore how hazardous an impact could be) you need the mass as well as the velocity.

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#### ginyoc

##### Guest
Re: asteroid 2009 KK May 29 2022

:lol: speaking of it: The Torino scale dropped to 0 today.
Palermo scale -2.24.
Now that was a fast descent.

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#### MichiganMan

##### Guest
Re: asteroid 2009 KK May 29 2022

ginyoc":1swaywke said:
:lol: speaking of it: The Torino scale dropped to 0 today.
Palermo scale -2.24.
Now that was a fast descent.

that makes sense, in a way... if it's a near miss, it will increase slowly, then rapidly fall off once impact is eliminated

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#### MeteorWayne

##### Guest
Re: asteroid 2009 KK May 29 2022

I haven't looked at this thread yet (I see MichiganMan posted) just have done my normal routine of looking at the ephemeris

Big changes today; it's almost like a whole different object in 2022. 105 observations over a 23 day arc.

CA went from .1921 to .2919 on May 13 (moving further away from the possible impact date)
Distance on May 29 went from .2243 to .3473
Plane crossing went from April 27th to March 14th...thats what I mean about it being like a whole different object.
JPL EMOID went up to .000644875 AU.

So the risk should plummet today, certainly a PS below -1.50 possible -2.00 or maybe even off the list!

We'll see....

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