chongo's Journal: 29 July 2002 01:00 UTC update for the 2002-NT7 asteroid

The orbit model for the 2002-NT7 asteroid has been updated to reflect 3 new observations. The model is based on 116 observations over a period of about 18 days, 15 hours.

The good news:

The Feb 1, 2019 and Feb 1, 2044 events are no longer considered close approaches and have been dropped from the hazard list.

The Feb 1, 2060 approach comes within ~13700 km instead of more narrow ~3570 km.

Because the Feb 1, 2019 and Feb 1, 2044 approaches are no longer close, the accuracy of the model >= 2060 has improved somewhat. However the model still remains somewhat uncertain, particularly after 2078.

The Palermo Scale value has changed from -0.25 to -0.89 (A lower number means less risk) However the Torino Scale remains at 1. (A value >0 means there is something to worry about). The main reason for the Palermo scale drop is that there are fewer close approaches to worry about over the next 50 years. Fewer close approaches means fewer risky events. Fewer risky events in the next 50 years results in a lower Palermo value.

The estimated size has been reduced from about 2.06 km to 2.03 km and the mass has been reduced from 1.2e13 kg to 1.1e13 kg.

The not so good news:

The odds of impact are slightly worse. The odds of an impact were about 1 in ~4,500,000 and now are about 1 in ~3,300,000. These odds reflect the additional post 2060 close approaches as well as an narrowing of most of the approaches that remain.

The improved model has produced an additional post 2060 close approaches:

1. Feb 1, 2053 (distance: ~22100 km)
2. Feb 1, 2060 (distance: ~13700 km)
3. Feb 1, 2062 (distance: ~11800 km) (new addition)
4. Feb 1, 2067 (distance: ~22400 km) (had been removed, now restored)
5. Feb 1, 2078 (distance: ~12700 km)

While the Feb 1, 2060 approach is not as close, the average approach is somewhat closer. We are not surprised to see the post 2060 approaches becoming closer.

So far, no pre-discovery images of 2002-NT7 have been found. A search of pre-discovery images is on-going.

Comment summary:

IMHO, It is still the case that there is next to nil chance of impact before 2060. It is 2060 and beyond events that are of concern. It is the pattern of orbit adjustments at and beyond 2060 that may be of concern.

The next model update will be sometime on or around 5 Aug 2002. Please revisit chongo's journal on or about that time.

We hope you have been enjoying these updates. Let us know that you enjoy these updates by becoming one our Friends. Click on the:

become chongo's friend

link and then click the Yup, I'm positive button.

As an added bonus be becoming a friend of chongo, when you go to your journal's main page, you will see a link to chongo's journal and the date of the last update.

See the Friends and Journals FAQ for more details.