2009 YG was a Torino Scale 1, now off the risk list 12/09

[silylene]

2009 YG is looking interesting. JPL has the PS cum = -1.92, 8 days of observational arc. And it's rather big.

 

[MeteorWayne]

Re: Newly discovered asteroids closely approaching earth.

Not only is it big (~ 800 meters) it's also in an eccentric orbit with aphelion in the outer asteroid belt, so the impact speed would be very high (>22 km/sec) which leads to a lot of energy.

I think I will start a new thread for new PHAs (Potentially Hazardous Asteroids) where we can put notices like this for new ones with short arcs...these two posts will be moved there. [Edit: Since 2009 YG has earned it's own thread, they have been re-moved to here]

BTW, arc is up to 9 days, now 5 impacts between 2033 and 2099 PS -2.26 cum, -2.51 max (2050). Note an unusual aspect of the impact dates; they vary from Jan 26 to Feb 6th...this shows how poorly the orbit is known, which is magnified because of the very low inclination (3.4 degrees). This makes it harder to accurately detrmine the nodal crossing date, which is the only time an earth impact can occur. With most, the impact date only varies by about a day for each year.

MW

 

[MeteorWayne]

2009 YG now a Torino Scale 1 risk asteroid

Today's data (45 observations over a 10 day arc) has this asteroid listed as a Torino Scale 1 for the 2050 virtual impactor (On NEODyS, JPL Sentry as not been updated yet). NEODyS PS for that impact -2.10. The 2033 risk is -2.49. More details later.

MW

 

[MeteorWayne]

Re: 2009 YG now a Torino Scale 1 risk asteroid

And for those new to risky asteroid tracking, here's what Torino Scale 1 means:

Normal
(Green Zone)
1
A routine discovery in which a pass near the Earth is predicted that poses no unusual level of danger. Current calculations show the chance of collision is extremely unlikely with no cause for public attention or public concern. New telescopic observations very likely will lead to re-assignment to Level 0.

 

[MeteorWayne]

Re: 2009 YG now a Torino Scale 1 risk asteroid

Interesting stuff in the Close approach table; in addition to Earth and Venus, this asteroid also has close approaches to "1". What is that? Well it's Dwarf Planet 1 Ceres!

http://newton.dm.unipi.it/neodys/index. ... 8&n=2009YG

Planet (Or Dwarf Planet)
Date
MJD
Nominal distance
(AU) Min possible distance
(AU) Stretching
(AU) Width
(AU) Close app probability

EARTH 1960/01/24.59128 ....36957.6 ....0.0216289 ....0.0210390.... 7.029e+1 ....6.326e-6 ....9.46e-4
EARTH 1974/07/08.25658 ....42236.3 ....0.0541195 ....0.0361476 ...3.181e+1 ....1.348e-5 ....2.02e-3
VENUS 1981/07/09.60643 ....44794.6 ....0.0238718.... 0.0237145.... 5.452e+0 ....1.050e-5 ....2.69e-3
EARTH 1999/07/17.79105 ....51376.8 ....0.1177530 ....0.0332014 ....5.035e+0 ....1.587e-5 ....1.15e-2
VENUS 2020/11/23.10459 ....59176.1 ....0.0225539 ....0.0194894 ....5.107e+0 ....5.852e-6 ....3.25e-3
1 ....... 2031/02/13.90987.... 62910.9 ...0.0463432.... 0.0212343 ....1.570e+1 ....9.324e-5 ....5.19e-4
VENUS 2038/11/10.79434.... 65737.8 ....0.0350524 ....0.0330526 ....3.879e+1 ....2.681e-5 ....3.87e-4
EARTH 2042/07/08.15713.... 67073.2.... 0.0464931 ....0.0306057 ....7.972e+1 ....2.043e-5 ....8.26e-4
1 ....... 2063/05/05.45517....74679.5 ....0.0221280.... 0.0216445 ....1.255e+2... 8.950e-5 ....1.24e-4
VENUS 2078/02/02.66883 ....80066.7 ....0.0479498 ....0.0215180 ....1.915e+2 ....4.672e-6 ....8.01e-5
EARTH 2092/07/20.02372 ....85348.0.... 0.1776370 ...0.0277838 ....2.842e+2 ....1.573e-5 ....1.74e-4

 

[silylene]

Re: 2009 YG now a Torino Scale 1 risk asteroid

MW, actually quite interesting. Close approaches to Earth, Venus and Ceres ! I have never seen a Ceres close approacher before, or for that matter, any asteroid which had cloase approaches to more than two planetary bodies.

And a close approach on Jul 17, 1999...and nobody knew about it.

And Torino Scale 1 !

 

[lekszikov]

Re: 2009 YG now a Torino Scale 1 risk asteroid

Dear Wayne !

What are the nominal distance on the risk date?
Why is Rms so high, and how could it effect to the risk numbers? (Higher rms vs. lower with the same data)

 

[MeteorWayne]

Re: 2009 YG now a Torino Scale 1 risk asteroid

The rms is high because it is a very short observational arc.

Here is the NEODyS risk page:

http://newton.dm.unipi.it/neodys/index. ... 2&n=2009YG

 

[MeteorWayne]

Re: 2009 YG now a Torino Scale 1 risk asteroid

JPL Sentry page has now been updated with 45 obs over 10.09 days. 6 potential impacts from 2033-2099. Size has decreased a bit to 776 meters.

Cumulative PS -1.84 (1 in 222,000 odds)
2050 impact PS -2.10 (1 in 455,000 odds)
2033 impact PS -2.48 (1 in 1.9 million odds)

 

[cyclonebuster]

Re: 2009 YG now a Torino Scale 1 risk asteroid

Stay away at least 200 miles from this guy!


Robert Marcus, H. Jay Melosh, and Gareth Collins
Please note: the results below are estimates based on current (limited) understanding of the impact process and come with large uncertainties; they should be used with caution, particularly in the case of peculiar input parameters. All values are given to three significant figures but this does not reflect the precision of the estimate. For more information about the uncertainty associated with our calculations and a full discussion of this program, please refer to this article

Your Inputs:
Distance from Impact: 322.00 km = 199.96 miles
Projectile Diameter: 776.00 m = 2545.28 ft = 0.48 miles
Projectile Density: 8000 kg/m3
Impact Velocity: 22.33 km/s = 13.87 miles/s
Impact Angle: 45 degrees
Target Density: 2750 kg/m3
Target Type: Crystalline Rock
Energy:
Energy before atmospheric entry: 4.88 x 1020 Joules = 1.17 x 105 MegaTons TNT
The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 8.8 x 105years
Atmospheric Entry:
The projectile begins to breakup at an altitude of 18600 meters = 60900 ft
The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 22.3 km/s = 13.8 miles/s
The impact energy is 4.85 x 1020 Joules = 1.16 x 105MegaTons.
The broken projectile fragments strike the ground in an ellipse of dimension 1.15 km by 0.814 km
Major Global Changes:
The Earth is not strongly disturbed by the impact and loses negligible mass.
The impact does not make a noticeable change in the Earth's rotation period or the tilt of its axis.
The impact does not shift the Earth's orbit noticeably.
Crater Dimensions:
What does this mean?



Crater shape is normal in spite of atmospheric crushing; fragments are not significantly dispersed.


Transient Crater Diameter: 13.1 km = 8.16 miles
Transient Crater Depth: 4.64 km = 2.88 miles


Final Crater Diameter: 18.5 km = 11.5 miles
Final Crater Depth: 0.712 km = 0.442 miles
The crater formed is a complex crater.
The volume of the target melted or vaporized is 3.05 km3 = 0.733 miles3
Roughly half the melt remains in the crater , where its average thickness is 22.5 meters = 74 feet
Thermal Radiation:
What does this mean?



Time for maximum radiation: 0.706 seconds after impact


Visible fireball radius: 7.58 km = 4.71 miles
The fireball appears 5.35 times larger than the sun
Thermal Exposure: 8.30 x 105 Joules/m2
Duration of Irradiation: 204 seconds
Radiant flux (relative to the sun): 4.07




Seismic Effects:
What does this mean?


The major seismic shaking will arrive at approximately 64.4 seconds.
Richter Scale Magnitude: 8.0
Mercalli Scale Intensity at a distance of 322 km:


VI. Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight.

VII. Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken.


Ejecta:
What does this mean?


The ejecta will arrive approximately 264 seconds after the impact.
At your position the ejecta arrives in scattered fragments
Average Ejecta Thickness: 7.95 mm = 0.313 inches
Mean Fragment Diameter: 5.35 mm = 0.211 inches


Air Blast:
What does this mean?


The air blast will arrive at approximately 976 seconds.
Peak Overpressure: 16700 Pa = 0.167 bars = 2.37 psi
Max wind velocity: 36.8 m/s = 82.4 mph
Sound Intensity: 84 dB (Loud as heavy traffic)
Damage Description:


Glass windows will shatter.

 

[JohnniG]

Re: 2009 YG now a Torino Scale 1 risk asteroid

And for those new to risky asteroid tracking, here's what Torino Scale 1 means:

Normal
(Green Zone)
1
A routine discovery in which a pass near the Earth is predicted that poses no unusual level of danger. Current calculations show the chance of collision is extremely unlikely with no cause for public attention or public concern. New telescopic observations very likely will lead to re-assignment to Level 0.

Oh, thanks for clearing that one up

 

[cyclonebuster]

Re: 2009 YG now a Torino Scale 1 risk asteroid

Wouldn't it be better if the Russians attacked this asteroid than Apophis? :mrgreen:

 

[MeteorWayne]

Re: 2009 YG now a Torino Scale 1 risk asteroid

No not really, since the orbit is not known with enough certainty to even be sure this is a real threat. You'd know that, if you had some clue as to what you were talking about...

 

[robnissen]

Re: 2009 YG now a Torino Scale 1 risk asteroid

No not really, since the orbit is not known with enough certainty to even be sure this is a real threat. You'd know that, if you had some clue as to what you were talking about...

MW, I defended you in the other post about the Russian's plans, but this time I think you are being unnecessaryly harsh. Once the orbit is shown to have no chace of impacting earth, I would much rather the Russians wasted their time monkeying with this orbit, than an asteroid that might hit the Earth after the Russians messed around with it. But I may be wrong and cyclonebuster may be wrong, but I certainly see no problem with him making that suggestion (as opposed to his drivel about capturing an asteroid).

 

[MeteorWayne]

Re: 2009 YG now a Torino Scale 1 risk asteroid

Perhaps you are right. I did let the other discussion affect the tone of my response in this thread.

Still, let's see what the orbit winds up like before we plan anything. It's FAR too short an observational arc to really have any idea how close it will come to the earth in the future. That's part of what planning such a mission requires.

Also, this asteroid has a very high approach velocity, requiring huge amounts of energy to change it's orbital path, and it's quite large also requiring lots of juice. Heck, it's 3 times the diameter (> 100 times the mass) of Apophis, and at 3 times the speed. Someone who does some actual research would come to the conclusion that the best asteroid for such a first experimental mission might be a small one that approaches the earth (not too close) at a relatively slow speed.

 

[MeteorWayne]

Re: 2009 YG now a Torino Scale 1 risk asteroid

New data, risk decreasing.

49 obs over 12 days, no longer TS1, it's dropped back to TS 0.

Cumulative PS is -2.63 (JPL), with 6 potential impacts from 2033-2099. The highest risk one is now in 2080; PS -2.97 (JPL), and PS -3.26 (NEODyS).

 

[Fallingstar1971]

Re: 2009 YG now a Torino Scale 1 risk asteroid

Nuclear powered catapult. Load up the UN building and lob it at the Asteroid. Multiple problems solved

So, it looks like the threat is getting lower and lower.

Is it a situation where if they know little about the asteroid it automatically gets a warning flag? Several times it was stated that the more observations we do the lower the threat gets.

So let me ask this. Are there any asteroids whos orbits have been refined, that have actually had there threat level increase?

Also, did STEREO ever find anything at the Lagrange points? Wasn't it speculated that pieces of the impacter that formed the moon may be there?

Star

 

[bdewoody]

Re: 2009 YG now a Torino Scale 1 risk asteroid

Nuclear powered catapult. Load up the UN building and lob it at the Asteroid. Multiple problems solved

So, it looks like the threat is getting lower and lower.

Is it a situation where if they know little about the asteroid it automatically gets a warning flag? Several times it was stated that the more observations we do the lower the threat gets.

So let me ask this. Are there any asteroids whos orbits have been refined, that have actually had there threat level increase?

Also, did STEREO ever find anything at the Lagrange points? Wasn't it speculated that pieces of the impacter that formed the moon may be there?

Star

I'd rather load up a bus full of lawyers.

 

[bdewoody]

Re: 2009 YG now a Torino Scale 1 risk asteroid

How's this for a constructive suggestion. The first NEO that is detected to have a high probability of hitting any one of the four inner planets should be the subject of a mission to deflect it from it's natural course. Hopefully we will detect such an object early enough to mount an attempt. I think most people don't have any concept of the amount of power it takes to deflect a large object just 1 degree from it's course. Too many people see Sci Fi movies and think we have those capabilities today.

Anyway I do believe such a mission should be undertaken on a NEO before a true threat is detected and close observations taken of the degree of success that is obtained. Waiting until a disaster is staring us in the face does not seem to be very smart.

 

[MeteorWayne]

Re: 2009 YG now a Torino Scale 1 risk asteroid

Is it a situation where if they know little about the asteroid it automatically gets a warning flag? Several times it was stated that the more observations we do the lower the threat gets.

So let me ask this. Are there any asteroids whos orbits have been refined, that have actually had there threat level increase?

Star

Well, since no asteroid seems likely to hit earth so far, the risk has gone down. The reason the higher risk exists in the beginning is because there's so much uncertainty in what the actual orbit is; there are a number of possible orbits that intersect earth. As more observations decrease the uncertainty (in other words, the spread of possible orbits that fit the data gets smaller) eventually fewer and fewer of the possible orbits hit us, so the risk declines. The exception of course would be one that actually is destined to hit earth, where the risk would continue to increase. So far, that has not been the case.

 

[robnissen]

Re: 2009 YG now a Torino Scale 1 risk asteroid

So let me ask this. Are there any asteroids whos orbits have been refined, that have actually had there threat level increase?

Star

As more observations decrease the uncertainty (in other words, the spread of possible orbits that fit the data gets smaller) eventually fewer and fewer of the possible orbits hit us, so the risk declines. The exception of course would be one that actually is destined to hit earth, where the risk would continue to increase. So far, that has not been the case.

Actually, there was an asteroid earlier this year where the risk did increase for a while. I'm too lazy to go find the thread, but as the risks increased for a while as the orbit got more refined, it got people a little excited here. But as the orbit got further refined, the risk went to zero, or at least, practically zero.

 

[MeteorWayne]

Re: 2009 YG now a Torino Scale 1 risk asteroid

There were actually two, 2009 KK in May/June (on page 3 here in SS&A) and 2009 WM1 on page 2.

 

[Gravity_Ray]

Re: 2009 YG now a Torino Scale 1 risk asteroid

Anyway I do believe such a mission should be undertaken on a NEO before a true threat is detected and close observations taken of the degree of success that is obtained. Waiting until a disaster is staring us in the face does not seem to be very smart.

Have you ever heard the line "You never hear the one that hits you", it’s related to incoming munitions. Well I suspect we will never see the one that hits us. One day we are like "la la la la la la" and the next day "WAM"... Bye bye self centered humans.

 

[bdewoody]

Re: 2009 YG now a Torino Scale 1 risk asteroid

Anyway I do believe such a mission should be undertaken on a NEO before a true threat is detected and close observations taken of the degree of success that is obtained. Waiting until a disaster is staring us in the face does not seem to be very smart.

Have you ever heard the line "You never hear the one that hits you", it’s related to incoming munitions. Well I suspect we will never see the one that hits us. One day we are like "la la la la la la" and the next day "WAM"... Bye bye self centered humans.

Unfortunately you are probably right. I just hope that if one gets through without detection it is small enough to do only local damage such as the Arizona crater. Then we would get going on a super active space program.

 

[MeteorWayne]

Re: 2009 YG now a Torino Scale 1 risk asteroid

Now with 53 observations over an 18 day arc, 2009 YG has been removed from both the JPL Sentry and NEODyS risk lists.