Risky asteroid 2009 WM1(Nov 2009)

[MeteorWayne]

I guess I have too much time on my hands

But 2009 WM1 passed 66.5 times the distance to the moon (0.17 AU) on Nov 14th.

It wasn't discovered until Nov 17th, and the observational arc is just over a day long, but it has popped to the top of the risk chart with a 1 in 625,000 chance of impact on Nov 22 2013 (PS -2.41), and 1 in 20,000 (PS -1.65) overall impact odds. It's a decent sized rock (~ 280 meters...range 220-490 meters) so would be a pain.

It's orbit is basically that of a Mars-Earth cycler, with aphelion near Mars' orbit, and perihelion near Earth's, except for the extreme 26 degree inclination.

As usual, further observations will likely lead to it disappearing from the risk list, but for a day or so, it's fun to watch.

 

[CommonMan]

Re: Just for fun, 2009 WM1

Good thing you said could impact in 2013 and not 2012! Oh my the threads we would get

 

[silylene]

Re: Just for fun, 2009 WM1

Let's watch this, will be fun.

 

[MeteorWayne]

Re: Just for fun, 2009 WM1

Good thing you said could impact in 2013 and not 2012! Oh my the threads we would get

Well....there is a 2012 impact listed :roll: , but the odds are very low, only 1 in 250 million (PS -4.81)

 

[MeteorWayne]

Re: Just for fun, 2009 WM1

NEODyS take on the object, much lower odds:

http://newton.dm.unipi.it/neodys/index. ... &n=2009WM1

Highest PS impact risk 11/22/2018, PS -2.98, no impact potential listed for 2012.

 

[MeteorWayne]

Re: Just for fun, 2009 WM1

Bad news for the 2012 doomsayers, but 2009 WM1 hung in there pretty good with another day of obs (only 2) Total arc now 2.02 days.
Down to 148 virtual impactors between 2018 and 2107, Cum PS -1.84 (1 in 28,000 odds), highest risk Nov 22, 2018 PS -2.24, odds 1 in 175,000.
NEODys has the PS for the 2018 VI at -2.48, odds about 1 in 300,000

 

[silylene]

Re: Just for fun, 2009 WM1

Ahhh, still interesting. 148 virtual impactors is a lot more than the usual. I hope we get some new observations and analysis tonight. Probably the list of virual impactors will get cut by another third.

 

[MeteorWayne]

Re: Just for fun, 2009 WM1

With the 1 day arc there were 989 impacts between 2012 amd 2108.

 

[3488]

Re: Just for fun, 2009 WM1

This is fascinating stuff.

I agree it will be fun to watch 2009 WM1.

I also wonder what type of asteroid this is?

It is approx half the size of the Type S Rubble Pile 25143 Itokawa. I wonder if they are indeed siblings???

Asteroids are fascinating little worlds for sure.

Andrew.

 

[MeteorWayne]

Re: Just for fun, 2009 WM1

Obs arc up to 3.02 days. Cum PS -1.99 (1 in 33,000), max PS -2.47 (1 in 111,000) Nov 22 2032.
94 VI's between 2018 and 2017.
Best guess size down to 272 meters.

NEODyS has come into much better agreement, with the 2032 VI PS= -2.46.

Interestingly, it shows a very close approach to earth on Nov 23 1979, before we had a seroius search program, of 0.0008341 AU (125,000 km, about 1/3 Lunar Distance).

The latest obs were by the LPL/Spacewatch II program.

 

[Shpaget]

Re: Just for fun, 2009 WM1

125000 km, wow, that's close.
How much panic would that kind of near miss generate today.

Anyway, if it hits the Earth I hope it lands in my backyard. It's probably worth millions.

 

[MeteorWayne]

Re: Just for fun, 2009 WM1

I must have been prescient when starting this thread. An increase in odds with the arc extended to 4 days with more obs from Spacewatch.

JPL has cumulative risk PS -1.69 (odds 1 in 20,000), highest PS -2.12 (odds 1 in 132,000) Nov 22, 2018.

87 VI's between 2018 and 2106.

Neodys has PS -2.14 for that event.

 

[Shpaget]

Re: Just for fun, 2009 WM1

So, am I getting rich or what?

srsly, should we start digging underground shelters?

 

[MeteorWayne]

Re: Just for fun, 2009 WM1

If it landed in your backyard, you, sir would be vaporized, so money would do you little good.

BTW, it is currently in the constellation Hydra, coincidentally just about where my field of view was at the end of my morning meteor session.

 

[silylene]

Re: Just for fun, 2009 WM1

The newest data is in, and analyzed by NeoDys:

Risk has increased.

Arc is now 6 days, 46 observations.
104 virtual impacts
Palermo Scale cumulative: -1.07
Palermo Scale max: -1.36
Torino Scale 1

cumulative probablility: 1 in 7246

Maybe need to change the thread title ?

 

[lekszikov]

Re: Just for fun, 2009 WM1

NEODys has new! TS 1 on 3 date
higher odds for 2018, 2027, and 2032.
I'm starting to worry. Please dear Wayne tell us something reassuring....

 

[silylene]

Re: Just for fun, 2009 WM1

NEODys has new! TS 1 on 3 date
higher odds for 2018, 2027, and 2032.
I'm starting to worry. Please dear Wayne tell us something reassuring....

We have been through this a few times before. Always, as we get enough data, the arc gets refined enough that we can disregard all the virtual impacts but one or two....and the odds of impact lessen with enough information to exclude collision.

I am sure we will go through that cycle again. It is fun to watch and speculate. Especially, based on the new observational data, to guess the new PS results, before the JPL and NeoDys computers complete their calculations....Wayne is good at this.

 

[MeteorWayne]

Re: Just for fun, 2009 WM1

Very interesting indeed. Perhaps I'll take the just for fun out of the thread title

I'll run some detailed projections of the 2018 encounter shortly to see what it says.

As silylene said, we've done this before, for several months IIRC for the last one. I'll dig up the old thread and bump it for educational purposes (also I'm curious what the highest risk PS was for that object).

 

[MeteorWayne]

Re: Risky asteroid 2009 WM1

Details of the 2018 encounter based on 46 obs through a 5 day arc.

Nominal close approach is .1185 AU (17.7 million km, or about 46x lunar distance) on Nov 17 2018 at ~ 06:00 UT.

Neodys impact risk is for Nov 22 2018 at 22:54 UT. The reason there is an impact risk at all is because of the huge uncertainty with such a small observational period of only 5 days.

For 2027, nominal CA is 0.0915 AU (13.7 million km, or 36 LD) on Nov 18 about 1200 UT; Neodys pisk time is Nov 23 about 05:15 UT.

 

[MeteorWayne]

Re: Risky asteroid 2009 WM1

OK, JPL Sentry Risk page has been updated.

Now a Torino Scale 1 object...just to review, there's the definition of TS1:


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.

103 potential impacts between 2018 and 2106.

Cumulative PS (Palermo Scale) -1.05 (Impact risk 1 in 6670)

2018 PS -1.33 (IR 1 in 23K)
2027 PS -1.57 (IR 1 in 20K)
2032 PS -2.05 (IR 1 in 45K)

 

[cyclonebuster]

Re: Risky asteroid 2009 WM1

Since the solutions have become worse since its discovery I ran a impact senerio. Don't be within 50 miles of this one for sure. YIKES!

Impact Effects at around 50 miles from center.
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: 80.50 km = 49.99 miles
Projectile Diameter: 280.00 m = 918.40 ft = 0.17 miles
Projectile Density: 8000 kg/m3
Impact Velocity: 18.10 km/s = 11.24 miles/s
Impact Angle: 45 degrees
Target Density: 2750 kg/m3
Target Type: Crystalline Rock
Energy:
Energy before atmospheric entry: 1.51 x 1019 Joules = 3.60 x 103 MegaTons TNT
The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 6.0 x 104years
Atmospheric Entry:
The projectile begins to breakup at an altitude of 15200 meters = 49800 ft
The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 17.9 km/s = 11.1 miles/s
The impact energy is 1.48 x 1019 Joules = 3.53 x 103MegaTons.
The broken projectile fragments strike the ground in an ellipse of dimension 0.503 km by 0.356 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: 5.39 km = 3.35 miles
Transient Crater Depth: 1.91 km = 1.18 miles


Final Crater Diameter: 6.75 km = 4.19 miles
Final Crater Depth: 0.526 km = 0.327 miles
The crater formed is a complex crater.
The volume of the target melted or vaporized is 0.0931 km3 = 0.0223 miles3
Roughly half the melt remains in the crater , where its average thickness is 4.08 meters = 13.4 feet
Thermal Radiation:
What does this mean?



Time for maximum radiation: 0.274 seconds after impact


Visible fireball radius: 4.4 km = 2.73 miles
The fireball appears 12.4 times larger than the sun
Thermal Exposure: 9.46 x 105 Joules/m2
Duration of Irradiation: 63.8 seconds
Radiant flux (relative to the sun): 14.8


Effects of Thermal Radiation:


Much of the body suffers first degree burns



Seismic Effects:
What does this mean?


The major seismic shaking will arrive at approximately 16.1 seconds.
Richter Scale Magnitude: 7.0
Mercalli Scale Intensity at a distance of 80.5 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 129 seconds after the impact.
Average Ejecta Thickness: 1.45 cm = 0.569 inches
Mean Fragment Diameter: 7.48 cm = 2.95 inches


Air Blast:
What does this mean?


The air blast will arrive at approximately 244 seconds.
Peak Overpressure: 24400 Pa = 0.244 bars = 3.47 psi
Max wind velocity: 52.4 m/s = 117 mph
Sound Intensity: 88 dB (Loud as heavy traffic)
Damage Description:


Interior partitions of wood frame buildings will be blown down. Roof will be severely damaged.

Glass windows will shatter.

About 30 percent of trees blown down; remainder have some branches and leaves blown off.



Tell me more...
Click here for a pdf document that details the observations, assumptions, and equations upon which this program is based. It describes our approach to quantifying the important impact processes that might affect the people, buildings, and landscape in the vicinity of an impact event and discusses the uncertainty in our predictions. The processes included are: atmospheric entry, impact crater formation, fireball expansion and thermal radiation, ejecta deposition, seismic shaking, and the propagation of the atmospheric blast wave.

 

[lekszikov]

Re: Risky asteroid 2009 WM1

Neodys has new, risk is higher again. :?

I dont understand this: Sigma LOV : yesterday 0.24849 today 0.631, yesterday 0.11525 today 0.444
and the site : Zero indicates the best-fitting, central (nominal) orbit and the further from zero, the less likely the event

so the sigma is further from 0 , but the risk is higher. Why?

Wayne ! Please write for me something about close aproach on risk dates ...

 

[F111F]

Re: Risky asteroid 2009 WM1

Cyclonebuster: I noticed you used iron for density, when the current best guess is that it's dense rock. Using dense rock also gets a pre-atmospheric energy match with the Impact Risk assessment (of course they are all just guesses based on albedo and could be way off). I recalculated, and about 50 miles out you're pretty safe, but that still means about 7,853 square miles of devastation for one 208m hunk of rock...

I am curious though, the impact effects program gives some weird results for ejecta. For instance, if you put in a distance of only 5 miles away, the mean ejecta thickness is 11.6ft, but the mean fragment diameter is 72.8ft. So, does that mean a few big rocks with lots of space to dodge them? :? (assuming you didn't spontaneously combust from the irradiance or get seriously tossed about by the sesmic and wind events...)

 

[MeteorWayne]

Re: Risky asteroid 2009 WM1

First some data updates. Now 49 obs over a 6 day arc.

NEODys 2018 PS dropped from -1.36 to -1.26; 2027 from -1.59 to 1.47, and 2032 is now -1.90 (I didn't write it down yesterday).

Nominal close approach has greatly increased for both 2018 and 2027.

2018 from 0.1185 to 0.2131 AU (83 LD), 2028 from 0.0915 to 0.2714 AU (106 LD).

I'll add JPL PS readings when the Sentry page updates.

EMoid decreased from 0.00044 to 0.00041.

So the orbit is closer, but the position of 2009 WM1 along the asteroid orbit at closest approach has increased.

I think the reason the risk has increased is because apparently the latest observations have increased the uncertainty in the orbital velocity.

 

[lekszikov]

Re: Risky asteroid 2009 WM1

more observations vs. bigger uncertainty hmm
isn't it a paradox?

(sorry for my silly questions...)