chongo's Journal: 2002-TC9 asteroid update for 2002-Oct-04 22:00 UTC

We have a new entry at the top of the current impact risks called 2002-TC9.

This object appears to be of significant size: ~1.12 km although its impact velocity (IF, and I do mean IF it were to hit the earth) is low to mid range: ~14.7 km/sec. If it were to hit the Earth, the effects would result in significant regional devastation.

The chance of impacting the Earth in the next 100 years is quite low: about 1 in ~1,500,000. The 1st close approach is not until 1 April 2011. (no fooling) The model shows over the next 100 years the closest approach is about 77,000 km with most of the other ''close'' approaches being 10x to 25x that distance.

It is very likely that over the next few days or weeks, additional observations will allow the model for 2002-SM to be refined. We see no long term trend in the model that would suggest that the risk from this object will become significant over the next few thousand years. It would not surprise us to see a refined model reducing the impact risk to the point where this object is removed from the potential Earth impactor table.

It should be noted that 2002-TC9's listing is very preliminary with only 27 observations spanning only about 30 hours ... not much on which to form an accurate model.

P.S. There is no change is status for 1997-XR2. That asteroid remains as the only non-zero Torino impact hazard scale object. The only reason why 2002-TC9 is listed higher than 1997-XR2 is because its Palermo scale is only 0.06 higher. It is very likely that the next set of 2002-TC9 observations will drop it down the list, if not off of the list.

Thanks!

[Shanes]

I just want to thank you for the work you put into your journal updates on this topic. Just in case you wonder if anyone actually reads them: I do, and with very much interest.

Btw: Are there any mailinglists/archives with discussions around this? I have a few more or less newbie questions that I haven't found answered on the Impact risc faq [nasa.gov] and elsewhere, but that have most likely been answered many times wherever this is discusted.

Thanks again!

Re:Thanks!

[chongo]

``I just want to thank you for the work you put into your journal updates on this topic. Just in case you wonder if anyone actually reads them: I do, and with very much interest.''

Thank you for your kind words.

``Btw: Are there any mailinglists/archives with discussions around this?''

I suspect that general some astro mailing lists/archive talk about asteroid hazards when the topic is in the news, but to my knowledge there are none to my knowledge that focus on potential impactors.

Folks: Feel free to post links to lists that directly or indirectly focus on Potentially Hazardous Asteroids if you find them.

``I have a few more or less newbie questions ...''

Ask away. I'm sure that others may be interested in the Q/A as well. ... and if I answer them wrong (or fail to answer them) others will step in and correct / fix things in traditional /. fashion. :-)

Re:Thanks!

[Shanes]

Wow! Thanks!
I'd say this should be worth a Q&A session on Slashdot's front page. But anyway, Here are my questions:

I notice that many potential impacts have 2 dates that are virtually the same. 1997 XR2's [nasa.gov] 2 impacts, for instance, differ with just 0.01 days. Why aren't they considered the same potential impact (which in some cases could give it a higher Torino scale number)?

What's the deal with the Hazardous NEO Technical Reviews [mit.edu]? Does it mean that a potentially hazardous impact with a Torino value > 1 would be kept off the jpl and NEODyS lists (and even in your journal!) until the Committee find it in its heart to tell the rest of us?
I find it hard to believe that such things could be kept secret since the observations are public and everyone can (in theory) make their own calculations based on them. Right?

How computational expensive are the the models?
The jpl model takes the gravitational effects of the 3 biggest asteroids into consideration and I've noticed that 2002NT7 [unipi.it] is listed with a close approach to the second largest asteroid, Pallas, in 2020. So I guess even the small masses of these asteroids are worth having in the model. But why do they stop there? Why isn't Juno and other large asteroids accounted for? Is this a trade off of accuracy vs computational time?
Watching the hazard lists it seems that the only thing influencing the numbers are more observations, not more time to calculate. How long does it take to calculate a trajectory 100 years ahead given a set of observations?

Finally: Has there ever been a potential impact listed with a Torino value >1?

Thanks!