Discovery [1] | |
---|---|
Discovered by | LINEAR |
Discovery site | Lincoln Lab's ETS |
Discovery date | 9 July 2002 |
Designations | |
(163348) 2002 NN4 | |
2002 NN4 | |
NEO · PHA · Aten [1] [2] | |
Orbital characteristics [2] | |
Epoch 31 May 2020 ( JD 2459000.5) | |
Uncertainty parameter 0 [2] · 2 [1] | |
Observation arc | 14.16 yr (5,171 d) |
Aphelion | 1.2572 AU |
Perihelion | 0.4956 AU |
0.8764 AU | |
Eccentricity | 0.4345 |
300 days | |
83.774 ° | |
1° 12m 4.68s / day | |
Inclination | 5.4177° |
259.48° | |
222.23° | |
Earth MOID | 0.0069 AU (2.69 LD) |
Physical characteristics | |
Mean diameter | |
14.50±0.03 h [5] [a] | |
X [3] | |
20.1 [1] [2] [4] | |
(163348) 2002 NN4 ( prov. designation: 2002 NN4) is a dark, sub-kilometer near-Earth object and potentially hazardous asteroid of the Aten group that flew by Earth on 6 June 2020. The highly elongated X-type asteroid has a rotation period of 14.5 hours and measures approximately 0.7 kilometers (0.4 miles) in diameter. [2] [6] It was discovered by LINEAR at the Lincoln Laboratory's Experimental Test Site in New Mexico on 9 July 2002. [1]
2002 NN4 flew by Earth on 6 June 2020, passing 0.034 AU (5.1 million km; 13 LD) from Earth. [2] The asteroid had been recovered two days earlier on 4 June 2020. [1] By 11 June 2020, the asteroid had brightened to apparent magnitude 14.4, which is roughly the brightness of Pluto.
Being a member of the Aten asteroids, 2002 NN4 orbits the Sun at a distance of 0.50–1.26 AU once every 10 months (300 days; semi-major axis of 0.88 AU). Its orbit has an eccentricity of 0.43 and an inclination of 5 ° with respect to the ecliptic. [2] It was first observed by the Near-Earth Asteroid Tracking on Palomar Observatory on 2 July 2002, or seven nights prior to its official discovery observation by LINEAR. [1] This asteroid has an Earth minimum orbit intersection distance of 0.0069 AU (1,030,000 km), which corresponds to 2.7 lunar distances (LD). [2]
A spectroscopic survey of the small near-Earth asteroid population conducted by European astronomers determined that 2002 NN4 is an X-type asteroid. [3] [6] Because of the objects low albedo (see below), it would be considered a primitive P-type asteroid in the Tholen classification.
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, 2002 NN4 measures (735±243) meters in diameter, and its surface has a dark albedo of (0.030±0.027). [4] (The NEOWISE publication uses the designation G3348 for this asteroid. [7]) In 2016, astronomers using the European New Technology Telescope at La Silla Observatory found a diameter of 613 meters with an albedo of 0.047. [3]: 4
In August 2016, the first rotational lightcurve of 2002 NN4 was obtained from photometric observations over five nights by Brian Warner at the Center for Solar System Studies ( U82) in California. Lightcurve analysis gave a rotation period of 14.50±0.03 hours with a high brightness variation of 0.74±0.05 magnitude, indicative of a highly elongated shape ( U=3−). [5] [a]