(89959) 2002 NT7 (prov. designation: 2002 NT7) is a near-Earth object with a diameter of 1.4 kilometers and potentially hazardous asteroid of the Apollo group.[2][3] It has a well determined orbit with an observation arc of 64 years including precovery images by Palomar Observatory dating back to 1954.[3]
| Discovery[1] | |
|---|---|
| Discovered by | LINEAR |
| Discovery site | Lincoln Lab's ETS |
| Discovery date | 9 July 2002 |
| Designations | |
MPC designation | (89959) 2002 NT7 |
Alternative designations | 2002 NT7 |
Minor planet category | |
| Orbital characteristics[2] | |
| Epoch 23 March 2018 (JD 2457800.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 62.68 yr (22,894 days) |
| Aphelion | 2.6529 AU |
| Perihelion | 0.8180 AU |
Semi-major axis | 1.7355 AU |
| Eccentricity | 0.5286 |
Orbital period (sidereal) | 2.29 yr (835 days) |
Mean anomaly | 79.375° |
Mean motion | 0° 25m 51.96s / day |
| Inclination | 42.333° |
Longitude of ascending node | 132.08° |
Argument of perihelion | 300.67° |
| Earth MOID | 0.0004 AU (60,000 km; 37,000 mi) |
| Physical characteristics | |
Mean diameter | 1.407±0.085 km[4] |
Geometric albedo | 0.224±0.053[4] |
Absolute magnitude (H) | 16.4[2] |
2002 NT7 became the first object observed by NASA's NEO program to be assigned a positive rating on both the Torino Scale and the Palermo Technical Impact Hazard Scale,[5] for a small chance of an impact on 1 February 2019, although it has now been known for years that it would pass Earth at roughly 0.4078 AU (61,010,000 km; 37,910,000 mi) on 13 January 2019 with an uncertainty region of around ±108 km.[6]
It was discovered on 9 July 2002 by the Lincoln Near-Earth Asteroid Research team (LINEAR) at the U.S. Lincoln Laboratory Experimental Test Site near Socorro, New Mexico.[1] At the time of discovery it only had a 6-day observation arc of 9–14 July,[1] which poorly constrained possible future positions of the asteroid.
Despite inflammatory press reports, the object had a "low probability" of impact, approximately one in a million, for 1 February 2019.[7] On 22 July 2002, NEODyS posted a positive 0.18 Palermo Scale rating.[5] Further observations of the object quickly lowered the probability. On 25 July 2002, the hazard rating on the Palermo scale was lowered to −0.25. However, the discovery of the object with a Palermo initial rating of 0.06[8] was a historical event for the NEO observation program.
2002 NT7 was removed from the Sentry Risk Table on 1 August 2002 (23 days after discovery), meaning there is no risk of an impact by it in the next 100 years.[9] On 13 January 2019, the asteroid safely passed 0.4078 AU (61,010,000 km; 37,910,000 mi) from Earth with a 3-sigma uncertainty region of about ±108 km.[6] Between 1900 and 2195 the closest approach to Earth will occur on 15 January 2099 at a distance of roughly 0.3739 AU (55,930,000 km; 34,760,000 mi) with an uncertainty region of about ±430 km.[6]
On 30 January 2020, the asteroid safely passed 0.02718 AU (4,066,000 km; 2,527,000 mi) from 2 Pallas.[10]
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