Newly discovered asteroids closely approaching earth.

[asterannie]

Thanks, Pete. Yes, I found that listing on the JPL database and that's why I was wondering about what the scientist had said. I am NOT a conspiracy theorist, but is it in the realm of possibility that they would just not post/talk about such extemely close possibilities. I would think with all the telescopes out there (privately held) that they couldn't keep it a secret. It was interesting, however, that FD's first miss on March 27, didn't show up until after the fact (on Spaceweather.com) - or am I mistaken in that also? (I think the same was the case with another very close flyby earlier in March -- hmmm...DD45 I think it was.)

Thanks for any light anyone can shed on this. I guess I'm just a big worry wart!

 

[MeteorWayne]

2009 FD was on the JPL Sentry close approach page:

http://neo.jpl.nasa.gov/ca/

for several days before the close approach. I had it in my notes but got sidetracked by the shuttle landing and the 2008 TC3 News conference and forgot to post about it in this thread. My bad...

The designation 2009 FD tells you it was the 4th of at least 775 asteroids discovered during the period from March 16-31, so most likely it was announced on the 16th or 17th.

MW.

 

[MeteorWayne]

On 8 May 2009, 2009FD is actually somewhat close to Venus.

Yes that's about 0.1 AU, so somebody probably got their planets and distance measurements (AU vs LD) confused.

It's really a pretty unusual asteroid in that it comes close to Venus, Earth, and Mars at various times. That's not terribly surprising considering it's very small inclination (~ PI degrees )

 

[MeteorWayne]

BTW, asterannie, Welcome to Space.com.

If you look on page 1 of this thread, you will see there have been several MUCH closer approches to earth in the last month or so than 2009 FD!

 

[MeteorWayne]

Thanks, Pete. Yes, I found that listing on the JPL database and that's why I was wondering about what the scientist had said. I am NOT a conspiracy theorist, but is it in the realm of possibility that they would just not post/talk about such extemely close possibilities. I would think with all the telescopes out there (privately held) that they couldn't keep it a secret. It was interesting, however, that FD's first miss on March 27, didn't show up until after the fact (on Spaceweather.com) - or am I mistaken in that also? (I think the same was the case with another very close flyby earlier in March -- hmmm...DD45 I think it was.)

Thanks for any light anyone can shed on this. I guess I'm just a big worry wart!

I have found that Spaceweather.com is pretty slow to update their Near Earth Asteroid section, which is at the bottom or their front page. They did however add 2009 FD on March 21st:

http://www.spaceweather.com/archive.php ... &year=2009

They just didn't do the front page article on it until the day of the closest approch, since 1.6 Lunar Distance isn't really very close by recent standards.

Meteor Wayne

 

[asterannie]

Fascinating stuff. Thanks for the welcome. I'll be keeping up with your information.

 

[MeteorWayne]

(Originally written 4/1)

2009 FP32 is one of the many tiny asteroids that we now detect a day or two before closest approach, only 7.5 to 17 meters in diameter. It was first observed on the 29th, and had closest approach yesterday March 31. It is on the risk page with 14 potential impacts between 2073 and 2104. Thise will likely decrease if more observations come in. Before the current surveys were started a few years ago, we never even would have seen it at all, due to it's small size, even at lunar distance.

MW

 

[MeteorWayne]

Catching up here, needed to add 3 objects to this list

2009 JL2 17-38 meters in size observed May 12-13, close approach at 0.7 LD May 13th.
4 Potential impacts from 2057-2085, max Palermo scale -5.69 (veryveryverylow risk) Only observed near CA for 1.24 days

2009 KW2 12-27 meters, observed May 22-29. Passed by 1.3 LD on May 24th. Not a future impacts risk

2009 KR21 12-26 meters, discovered May 31, Close approach today June 1 at 0.7 LD. Not a future impact risk.

 

[MeteorWayne]

The newly discovered 2009 MU (31-70 meters) will pass 2.3 LD from the earth tomorrow the 24th, and has 2 very low risk impact possibilities in 2096 and 2099

 

[silylene]

Hello Wayne,

Let's keep a watch on 2009SG18. very newly discovered and big, PS = -2.06. Still only a tiny chance of collision with 34 passes to earth in the next century.

 

[MeteorWayne]

I noticed it yesterday, the odds were a lot lower then, with more VI's beginning in 2015. SO since the odds have gone up, we should keep an eye on it. If the PS goes up again, we'll start a dedicated thread.

It is a big one (~900m) but it's only a 3 day arc.

 

[MeteorWayne]

On a related note, interesting article in the Sept 18 Science about "An Anomamous Basaltic Meteorite from the Innermost Main Belt"

Briefly (ha!) the fireball was detected by the Desert Fireball Network in Australia on 20 July 2007, and based on the path, not only was the unusual pre impact orbit determined, but 2 pieces (150 and 174g) were recovered. The object was luminous from 62.8 km to 29.6 km in height along it's 65 km long path.The authors calculated the largest fragments were in the range of 100 to 250 g, so searched along the flight path where objects of that size would have wound up. (Heavier objects travel further, lighter ones not as far, so based on the speed you can roughly predict how far a mass of a certain size will travel.) The two recovered pieces were 97 meters south and 29 meters north of the projected path center line.

Turns out the orbit was an Aten orbit (earth crossing but with a < 1 AU) with perihelion inside Venus' orbit and aphelion just outside of earth's.

It was close to a V-type asteroid (which are in general believe to be derived from Vesta, whch was at one point a completely molten, hence differentiated asteroid) but there were overal important differnces which indicate it is a nearly unique type. First it has 3 different distinct grain sizes (unlike the typical eucrite). The finest grains are close in O isotopic ratios to a class called angrites (n=3) and a meteorite called Ibitira (brazil 1957). But only one other recovered meteorite came close to the bulk comosition, Asuka-881349 (Queen Maud Land Antarcita, 1988).

They projected the orbit backwards, finding a close approach to Venus in 2001 and earlier close approches to earth. (The orbital period would have been ~ 300 days). Using a numerical model they determined the most likely source region was the innermost asteroid belt with 98% probability. There was a 72% chance it came form the Saturnian v6 secular resonance, 26% that it came from many small Jupiter mean motion resonances in the inner belt, and 2% that it came from the Jupiter 3:1 motion resonance. The outer main belt (>2.8 AU) and Jupiter family comets were ruled out as possible sources.

So that's two meteorites with known orbits discovered in the last 2 years based on observations; 2008 TC3 in the sudan based on pre impact NEO detection, and this from a fireball network.

I'll try and find an online link.

MW

 

[silylene]

MW, thanks for the information on the Australian fall. the fireball network as a concept really seems promising. Perhaps it would be good to install such a network on Antarctica too...It may allow for an even more pristine environment to gather the meteorites, and maybe an easier find too.

 

[MeteorWayne]

2009 SN103 will pass within 1.2 LD on Sept 28. It's a small (8-17 meter) asteroid discovered on 9/25. I should point out that this is ~ the 2650th asteroid descovered during the last 2 weeks of September!

 

[MeteorWayne]

Another tiny asteroid passed by the earth early this morning at 0.9 lunar distance, 2009 TM8. It's about 6-13 meters in size. It has nearly a 2 year orbital period, so comes close to the earth every two years or so and is currently on the JPL risk page with currently 1 in 7000 odds of impact over 78 potential ones. The Palermo Scale is only -5.85 due to it's small size, it isn't a threat of causing significant damage. Highest risk impact is in 2108 with 1 in 33,000 chance. It has only a 2 day arc discovered Oct 15th.

http://neo.jpl.nasa.gov/risk/2009tm8.html

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2 ... ;cad=1#cad

 

[MeteorWayne]

Actually, we're still discovering large ones too.

2009 TK8 is about 400 meters, 2009 HC21 165 meters, 2009 RN 440 meters, 2009 SV171 550 meters, etc....

 

[MeteorWayne]

Next up, 2009 UD, a tiny (10-23 meter) rock passing 2 LD from earth on Oct 20th. It will pass close to the moon on the 21st. Discovered Oct 16th.

Not a future impact risk, at least so far.

 

[HopDavid]

Re:

Replying to:I guess what I find most disconcerting is the fact that several of these close distance meteors have passed by Earth *before* we even detected them.
Posted by michaelmozina

Yes, but that mostly applies to very small ones like this. In fact it was discovered 2 days after closest approach. That is also because it came out of the sunward direction.

One of the things that cause me anxiety are asteroids with an apohelion of around 1 A.U.

Such asteroids are very difficult to see for a number of reasons. And since they have shorter periods, they could approach the earth more frequently.

I am very hopeful that Canada's Neosat will give us more knowledge about the inner solar system asteroids.

 

[Smersh]

Have you guys heard about the estimated 10m wide object that is said to have exploded over Indonesia on 8th Oct, with "the energy of three Hiroshima bombs?" (I didn't see a thread about it here.)

Asteroid explosion over Indonesia raises fears about Earth's defences

 

[MeteorWayne]

Hi Smersh, and thanx again. I had not heard about the event. The video does appear to show a dust trail possibly left by a daytime bolide. I assume the rest of the report was as high quality as most media coverage ( :roll: ), but since I didn't understand the language, that's speculation Objects this size aren't really a threat, but it shows we have more work to do. The Telegraph report is a little hyped, as you might expect.

Second, thanx for the spam report. Don't know how I missed it. It has been vaporized, just like the bolide.

Third, I was just about to post about a new object which will pass within 1.6 LD on Halloween morning, 2009 UW87, 7-15 meters in diameter. Discovered Oct 27th

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2 ... ;cad=1#cad

 

[Smersh]

Hi Wayne, yes I figured the Telegraph report was quite possibly using a little "artistic licence." I wasn't sure if you'd be able to match it up with some report or other on one of the dedicated NEO sites you visit though.

As for the spammer, you're very welcome and thanks for hitting him with the force of three Hiroshima bombs.

 

[MeteorWayne]

Still searching for aother reports of the event...

SpaceWeather.com has a report on today's page. I didn't realize the event actually occurred Oct 8

Excerpts:

The asteroid that caused the blast was not known before it hit and took astronomers completely by surprise. According to statistical studies of the near-Earth asteroid population, such objects are expected to collide with Earth on average every 2 to 12 years. "Follow-on observations from other instruments or ground recovery efforts would be very valuable in further refining this unique event," say Silber and Brown.

http://www.spaceweather.com/archive.php ... &year=2009

 

[MeteorWayne]

SDC Story on the Indonesia event:

http://www.space.com/scienceastronomy/0 ... osion.html

"More data is expected from U.S. military space assets that likely detected the event. From their vantage point in space, multiple sensor systems would have seen the huge explosion and there surely is a rich dataset of measurements to be plumbed relating to the detonation. "

"The body was large enough that some of the current Spaceguard Survey telescopes might have detected it a couple of days before it hit, were it coming from the night sky. But it struck during daytime and probably could not have been seen by those telescopes," Chapman explained.

 

[MeteorWayne]

A very tiny asteroid (5-11 meter in diameter) 2009 VA, passed by earth yesterday at a very close distance, well inside the distance of Geostationary satellites. The pass was at ~ 20447 km from the earth's center or only ~14,000 km above the earth's surface.

It was discovered about 18 hours before closest approach.

It's currently on the JPL risk page with 9 low probability impacts beginning in 2025, however the observational arc is only a few hours long. Discovered by the Catalina Sky Survey.

 

[MeteorWayne]

A small asteroid (4-8 meter diameter) 2009 VT1 was iscovered about a day after it's closest approach to earth on Nov 9 at 1.4 LD.

Expanding the parameters a bit, 2009 VX 16-35 meters, will pass 2.6 LD from earth tomorrow.