Contents

2013 YP₁₃₉

2013 YP₁₃₉

Near-Earth asteroid 2013 YP139—the six red dots in the composite image by NEOWISE specify the location of the asteroid. The inset is an enlargement of the image of 29 December 2013.
Discovery[1]
Discovered by	NEAT[2] NEOWISE[3]
Discovery site	Palomar Obs.[2] Earth orbit[3]
Discovery date	29 June 2002[2] 29 December 2013[3]
Designations
MPC designation	2013 YP139
Alternative designations	2013 YP139 · 2002 MU7
Minor planet category	NEO · Apollo · PHA[2][4]
Orbital characteristics[4]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc	11.58 yr (4,231 days)
Aphelion	4.0373 AU
Perihelion	0.7603 AU
Semi-major axis	2.3988 AU
Eccentricity	0.6831
Orbital period (sidereal)	3.72 yr (1,357 days)
Mean anomaly	61.262°
Mean motion	0° 15m 55.08s / day
Inclination	0.8171°
Longitude of ascending node	292.13°
Argument of perihelion	83.598°
Earth MOID	0.0040 AU (1.56 LD)
Physical characteristics
Mean diameter	0.402±0.026 km[5] 0.650 km[1]
Geometric albedo	0.025±0.006[5]
Absolute magnitude (H)	21.6[4]

2013 YP₁₃₉ is a dark sub-kilometer asteroid on a highly eccentric orbit, classified as a near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 400 meters (1,300 feet) in diameter.^[4]

It was first observed as 2002 MU₇byNEATatPalomar Observatory on 29 June 2002, and by the WISE space telescope on 29 December 2013, under its current, principal provisional designation.^[2][3] This object was the first possible discovery of the reinstated NEOWISE program of the WISE telescope, following the program's hibernation in 2011.^[1]

Orbit and classification[edit]

2013 YP₁₃₉ belongs to the Apollo asteroids, which cross the orbit of Earth. They are the largest group of near-Earth objects with nearly 10 thousand known members.

This object orbits the Sun at a distance of 0.76–4.0 AU once every 3 years and 8.6 months (1,357 days; semi-major axis of 2.40 AU). Its orbit has an eccentricity of 0.68 and an inclination of 1° with respect to the ecliptic.^[4] Due to this close proximity, NASA has classified this object as a potential threat. At the time of the first WISE observations, this object was moving at a rate of 3.2° per day (for comparison the apparent diameter of the Moon is 0.5°).^[6]

Close approaches[edit]

2013 YP₁₃₉ has a minimum orbital intersection distance with Earth of 0.00397 AU (594,000 km; 369,000 mi), which corresponds to 1.6 lunar distances (LD).^[4] In August 2002 and December 2013, approached Earth at 4.1 LD and 94 LD, respectively. On 12 December 2069, it will pass Earth at a nominal distance of 0.007911 AU (1,180,000 km; 735,000 mi), or nearly 3 LD.^[4] It also makes close approaches to Jupiter, Venus, Mars and the Moon.^[4]

First WISE observations[edit]

The Wide-field Infrared Survey Explorer's Near-Earth Object WISE (NEOWISE) program was put into hibernation on 1 February 2011, following several program extensions,^[7] from which approximately 34,000 asteroids were detected.^[1] On 21 August 2013, however, the program was reactivated.^[7] The new mission of the NEOWISE was to identify the population of potentially hazardous near-Earth objects.

2013 YP₁₃₉ was first observed on 29 December 2013, at a distance of 0.235 astronomical units (35,200,000 kilometres; 21,800,000 miles) from Earth, marking the first object detected since the program's reinstatement. The infrared brightness was the primary attribute used for ascertaining the approximate size of the asteroid. Over the course of half a day, the trajectory of the asteroid was observed against the stationary positioning of the stars in the background.^[1]

The data from the Wide-field Infrared Survey Explorer was transmitted to the Infrared Processing and Analysis Center at the California Institute of Technology, located in Pasadena, California. To confirm the discovery, researchers at the University of Arizona utilized the Spacewatch telescope at the Kitt Peak National ObservatoryinTucson, Arizona. 2013 YP₁₃₉ is considered by NASA to be the first in what is expected to be thousands of objects to be detected by NEOWISE's new mission.^[8] Due to the trajectory of the asteroid, which puts it within a potentially dangerous range in over one hundred years following its discovery, NASA stated that they would keep a watchful eye on it.^[1]

Physical characteristics[edit]

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, 2013 YP₁₃₉ measures 0.402 kilometers in diameter and its surface has an exceptionally low albedo of 0.025.^[5] Estimates from 2014 gave a somewhat larger diameter of 0.650 kilometers (0.404 miles).^[1] Its very dark surface, has an albedo comparable to a piece of coal.^[1]

See also[edit]

• List of asteroid close approaches to Earth in 2013

References[edit]

External links[edit]

• List of the Potentially Hazardous Asteroids (PHAs), Minor Planet Center
• PHA Close Approaches To The Earth, Minor Planet Center
• 2013 YP139atNeoDyS-2, Near Earth Objects—Dynamic Site
  • Ephemerides · Observation prediction · Orbital info · MOID · Proper elements · Observational info · Close approaches · Physical info · Orbit animation
• 2013 YP139atESA–space situational awareness
  • Ephemerides · Observations · Orbit · Physical properties · Summary
• 2013 YP139 at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters