| Minorplanet: | yes |
| Background: |
|
| Discovery Ref: | [1] |
| Discoverer: | LINEAR |
| Discovery Site: | Lincoln Lab's ETS |
| Discovered: | 8 December 1998 |
| Mpc Name: | 1998 XX2 |
| Mp Category: | NEOAtenPHA |
| Alt Names: | MPO 251988, MPO 315368 |
| Orbit Ref: | [2] |
| Epoch: | 13 January 2016 (JD 2457400.5) |
| Uncertainty: | 0 |
| Observation Arc: | 5832 days (15.97 yr) |
| Aphelion: | 1.013611188abbr=onNaNabbr=on |
| Perihelion: | 0.46896072AU |
| Semimajor: | 0.741285953AU |
| Eccentricity: | 0.3673687 |
| Period: | 0.64 yr (233.1 d) |
| Avg Speed: | 33.3946406 km/s |
| Inclination: | 6.9722566° |
| Asc Node: | 74.444600° |
| Mean Motion: | 1.5442778°/day |
| Mean Anomaly: | 151.54037° |
| Arg Peri: | 153.00166° |
| Moid: | 0.0161402AU |
| Tisserand: | 7.716 |
| Mean Diameter: | 270–590 m[3] |
| Abs Magnitude: | 19.9 |
is a sub-kilometer asteroid, classified as a near-Earth object and potentially hazardous asteroid of the Aten group. It was discovered 8 December 1998, by the Lincoln Near-Earth Asteroid Research at Lincoln Laboratory's Experimental Test Site, and was found to have frequent approaches to the Earth, Venus, and Mercury.
The orbit of is well-established, and appears on the list of PHA close approaches to Earth, with the next approach at a distance of 0.020237abbr=onNaNabbr=on on 28 November 2028.[4] During the years 1900–2200, close approaches are 0.017abbr=onNaNabbr=on of the Earth (on 30 Nov 1991), as close as 0.035abbr=onNaNabbr=on of Venus (on 28 Jan 1902 and 8 April 2039), and as close as 0.029abbr=onNaNabbr=on of Mercury on 12 occasions. For comparison, the distance to the Moon is about 0.0026 AU (384,400 km).
From 1993 to 1998, was the asteroid with the lowest known aphelion at 1.023 AU, and was thus the closest thing to an Apohele asteroid known at the time. When was discovered 25 November 1998, it was found to have a slightly smaller aphelion (1.019 AU) than, so took the title. However, lost its smallest aphelion title almost immediately when (aphelion of 1.014 AU) was discovered only a few weeks later on 8 December 1998.
The Jupiter Tisserand invariant, used to distinguish different kinds of orbits, is 7.7.[2]