astro.wikisort.org - Asteroid

(505657) 2014 SR₃₃₉, provisional designation 2014 SR₃₃₉, is a dark and elongated asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 970 meters (3,200 feet) in diameter. It was discovered on 30 September 2014, by NASA's Wide-field Infrared Survey Explorer telescope (WISE) in Earth's orbit.[1] Closely observed at Goldstone and Arecibo in February 2018, it has a rotation period of 8.7 hours.[5]

(505657) 2014 SR₃₃₉

Radar images of 2014 SR339 taken by the Arecibo Observatory on 9 February 2018
Discovery[1]
Discovered by	WISE
Discovery site	Earth orbit
Discovery date	30 September 2014
Designations
MPC designation	(505657) 2014 SR339
Alternative designations	2014 SR339
Minor planet category	Apollo · NEO · PHA[1][2]
Orbital characteristics[2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc	3.41 yr (1,245 d)
Aphelion	1.6948 AU
Perihelion	0.9046 AU
Semi-major axis	1.2997 AU
Eccentricity	0.3040
Orbital period (sidereal)	1.48 yr (541 d)
Mean anomaly	60.524°
Mean motion	0° 39m 54.72s / day
Inclination	29.790°
Longitude of ascending node	138.78°
Argument of perihelion	299.60°
Earth MOID	0.0354 AU (13.8 LD)
Physical characteristics
Dimensions	(>1.5 km × ? km)[3]
Mean diameter	0.971±0.367 km[4]
Synodic rotation period	8–9 h[5] 8.729 h[3][lower-alpha 1]
Geometric albedo	0.068±0.074[4]
Spectral type	C(assumed on albeo)
Absolute magnitude (H)	18.6[2]

Orbit and classification

2014 SR₃₃₉ is a member of the Apollo asteroids, which cross the orbit of Earth. Apollo's are the largest group of near-Earth objects with nearly 10 thousand known objects. It orbits the Sun at a distance of 0.90–1.70 AU once every 18 months (541 days; semi-major axis of 1.30 AU). Its orbit has an eccentricity of 0.30 and an inclination of 30° with respect to the ecliptic.[2] With an aphelion of 1.70 AU, it is also a Mars-crosser, as it crosses the orbit of the Red Planet at 1.666 AU. The body's observation arc begins with its official discovery observation by WISE in September 2014.[1]

Close approaches

As a potentially hazardous asteroid, 2014 SR₃₃₉ has a minimum orbital intersection distance (MOID) with Earth of less than 0.05 AU and a diameter of greater than 150 meters. The Earth-MOID is currently 0.0354 AU (5,300,000 km), which translates into 13.8 lunar distances (LD).[2]

2018 flyby

On 7 February 2018 it passed 0.054 AU (21 LD) from the Earth when its apparent magnitude brightened to 14.[3] Goldstone observed it until the following day.[6] While this was an 8.1-million kilometer flyby, the next close flyby of 6.3 million km will occur on 5 February 2058, and another 7.6 million km on 8 February 2095. It will also have a 3.2 million km flyby of Mars on 26 September 2048.[7]

Physical characteristics

The asteroid's spectral type is unknown. Due to its unusually low albedo (see below) it is likely a carbonaceous C-type asteroid.[2]

Rotation period

On 9 February, radiometric observations by the Arecibo Observatory revealed that the asteroid has an elongated, lumpy shape.[3] The radar images also gave it a rotational period between 8 and 9 hours.[5] A refined period of 8.7 hour agrees with (photometric) lightcurve observations by American photometrist Brian Warner at the Center for Solar System Studies (U82) during 9–11 February 2018, who obtained a period of 8.729 hours with a high brightness amplitude of 0.93 magnitude, which also indicates a non-spheroidal shape (U=3-).[3][lower-alpha 1]

Diameter and albedo

According to the survey carried out by the NEOWISE mission of NASA's WISE telescope, 2014 SR₃₃₉ measures 0.971 kilometers in diameter and its surface has an albedo of 0.068.[4] During its close approach in February 2018, radiometric observations by Arecibo Observatory determined that the object is at least 1.5 kilometers (0.93 miles) wide.[3] Data from the Arecibo Telescope released in 2022 showed an unusually high radar albedo, possibly indicating rich metal content.[8]

Numbering and naming

This minor planet was numbered by the Minor Planet Center on 4 November 2017 (M.P.C. 107069).[9] As of 2018, it has not been named.[1]

Gallery

• 
  Daily motion of asteroid across sky
• 
  View of flyby above the earth and moon

Notes

References

External links

• List of the Potentially Hazardous Asteroids (PHAs), Minor Planet Center
• List Of Apollo Minor Planets (by designation), Minor Planet
• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• (505657) 2014 SR339 at NeoDyS-2, Near Earth Objects—Dynamic Site
  • Ephemerides · Observation prediction · Orbital info · MOID · Proper elements · Observational info · Close approaches · Physical info · Orbit animation
• (505657) 2014 SR339 at ESA–space situational awareness
  • Ephemerides · Observations · Orbit · Physical properties · Summary
• (505657) 2014 SR339 at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

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