Illustration of Earth with several asteroids passing at different distances, one flagged as potentially hazardous

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(2013 JR28)

Designation: 2013 JR28 · NASA id: 3638466 · Potentially Hazardous

Estimated diameter: 121 – 272 meters (absolute magnitude H = 21.7) · JPL Small-Body Database →

Why is one asteroid “hazardous” when closer ones are not?

Because the flag has nothing to do with how close it came on the day. NASA marks an object a Potentially Hazardous Asteroid only if both of these are true of its orbit and its size:

  • Its orbit can bring it within 0.05 AU of Earth’s — about 7.5 million km. This is the Minimum Orbit Intersection Distance, the closest the two paths ever come, not the distance on any given pass.
  • It is big enough to matter — absolute magnitude 22.0 or brighter, which is roughly 140 metres across and up. That threshold is a planning convention, not a physical boundary: it is about the size at which an impact could do regional damage. Smaller objects are not harmless, they are simply outside this definition — the Chelyabinsk object of 2013 was around 20 metres and injured about 1,500 people with the shock wave from its airburst, without ever reaching the ground intact.

The two terms: AU — astronomical unit, the average Earth–Sun distance, 149,597,871 km. 0.05 AU is about 7.5 million km.
MOID — minimum orbit intersection distance, the closest the two orbits ever come, whatever the timing. See the glossary for NEO, PHA and H.

So a large rock passing at 39 million km today can be flagged, because on some future orbit it could come far nearer — while a pebble skimming past at 4 million km is not, because it would never reach the ground.

Three objects that all passed Earth on 30 August 2026 make the point better than any definition:

Object Size Orbit’s closest to Earth’s Missed by, that day Flagged
2013 JR28 122–272 m 5.3 M km (0.035 AU) 39.2 M km Yes — both tests pass
2012 LE11 629–1,406 m 23.3 M km (0.156 AU) 26.1 M km No — orbit never gets near enough
2007 EK 3.7–8.2 m 198,000 km (0.0013 AU) 4.2 M km No — far too small

The middle one is five times larger than the flagged one and passed closer on the day, but its path can never come within 23 million km of ours. The last one’s orbit crosses inside the Moon’s distance — nearer than any other object here — and it is still not hazardous, because at a few metres across it would burn up long before it landed.

“Potentially hazardous” is a watchlist criterion, not a prediction. None of these is on a collision course; the label means an object is worth keeping precise track of over the coming centuries.

Orbital Data

Orbit class: APO — Near-Earth asteroid orbits which cross the Earth’s orbit similar to that of 1862 Apollo
a (semi-major axis) > 1.0 AU; q (perihelion) < 1.017 AU

Orbital period1,192.7 days (3.27 years)
Eccentricity.6547443507930789 (0 = circular, closer to 1 = more elongated)
Semi-major axis2.200977009222278 AU
Inclination6.552587500087297° (tilt of its orbit vs. Earth's)
Perihelion distance.7598997462085449 AU (closest approach to the Sun)
Aphelion distance3.642054272236011 AU (farthest from the Sun)
Minimum Orbit Intersection Distance0.03549 AU = 5,309,228 km
(closest its orbit path ever comes to Earth's, regardless of timing)
Ascending node longitude103.5348592434947°
Argument of perihelion230.5529106468504°
Mean anomaly / motion275.1453813196343° / .3018427957777959°/day
Jupiter Tisserand invariant3.341 (helps distinguish asteroids from comets)
Reference epoch / equinoxJD 2461000.5 / J2000
Orbit determined2021-04-15 08:10:41
Observed2013-05-12 to 2013-06-18 (37 day arc, 304 observations used)
Orbit uncertainty2 (0 = best known, 9 = least certain)

Close Approach History

Every close approach NASA has on record for this object — 43 total.

Why does it pass Earth, Venus and Juptr? Doesn’t it orbit just one?

It orbits the Sun. Not Earth, and not Venus. The column above does not say what the asteroid goes around — it says which planet a given close approach was to. 26 of them were approaches to Earth, 10 of them were approaches to Venus and 7 of them were approaches to Juptr.

This one’s path runs from 0.760 AU at its closest to the Sun out to 3.642 AU at its farthest. For scale, Venus orbits at about 0.72 AU and Earth at 1.00 AU — so an orbit spanning that range crosses the path of every planet in between, once on the way out and once on the way back.

Crossing a planet’s path is not the same as meeting the planet. Almost every time the asteroid crosses, that planet is somewhere else along its own orbit. A close approach is logged only on the rare occasions when both happen to arrive at the crossing point at roughly the same time — which is why the dates below are scattered rather than regular. This object takes 1192.7 days to go round, against Earth’s 365.25, so the two drift in and out of step over years rather than repeating on a neat cycle.

The Minimum Orbit Intersection Distance in the table above (0.0355 AU) is the closest the two paths ever come. The miss distances below are how far apart the two bodies actually were on the day, which is almost always very much larger.

next approach: 2039-11-12

Date Passed near Velocity (km/h) Miss distance
2196-11-25 Earth 96544.89 52,015,103 km
135 LD
2193-05-23 Earth 111155.62 71,558,489 km
186 LD
2183-09-22 Earth 49155.25 35,929,583 km
93.5 LD
2182-01-07 Juptr 13055.67 278,599,279 km
725 LD
2170-06-22 Earth 58917.14 5,112,423 km
13.3 LD
2160-11-21 Earth 89606.77 43,010,085 km
112 LD
2150-12-06 Venus 55446.35 20,257,056 km
52.7 LD
2147-10-07 Earth 46613.70 31,579,279 km
82.2 LD
2145-12-23 Juptr 12654.03 266,624,519 km
694 LD
2141-02-16 Venus 34776.18 6,362,950 km
16.6 LD
2134-06-22 Earth 58451.09 5,583,630 km
14.5 LD
2131-05-07 Venus 46276.29 16,166,641 km
42.1 LD
2124-11-21 Earth 90163.21 43,894,175 km
114 LD
2111-10-22 Earth 47810.87 24,138,595 km
62.8 LD
2098-07-18 Earth 47750.72 28,707,931 km
74.7 LD
2087-02-26 Juptr 13268.70 284,822,537 km
741 LD
2085-05-30 Earth 92893.31 45,741,618 km
119 LD
2078-12-24 Venus 37728.52 7,340,596 km
19.1 LD
2075-11-06 Earth 63369.34 15,057,209 km
39.2 LD
2069-03-17 Venus 46432.65 16,054,879 km
41.8 LD
2062-08-06 Earth 50996.13 36,143,316 km
94.0 LD
2051-02-14 Juptr 12628.01 263,725,376 km
686 LD
2049-06-06 Earth 79486.08 27,321,317 km
71.1 LD
2039-11-12 next Earth 74002.32 24,009,619 km
62.5 LD
2026-08-30 Earth 52867.88 39,176,126 km
102 LD
2016-11-01 Venus 40403.96 9,032,054 km
23.5 LD
2015-02-05 Juptr 13947.24 295,905,486 km
770 LD
2013-06-18 Earth 61166.98 5,213,263 km
13.6 LD
2007-01-02 Venus 36141.85 7,724,604 km
20.1 LD
2003-11-10 Earth 72710.41 23,090,951 km
60.1 LD
1997-03-01 Venus 35553.26 7,074,984 km
18.4 LD
1992-03-24 Juptr 13560.61 283,869,621 km
738 LD
1990-07-06 Earth 48792.42 22,207,079 km
57.8 LD
1987-04-19 Venus 45423.30 12,566,733 km
32.7 LD
1980-11-18 Earth 89045.05 42,174,657 km
110 LD
1977-06-11 Venus 52229.32 19,158,902 km
49.8 LD
1967-07-13 Earth 48076.61 26,828,948 km
69.8 LD
1957-11-16 Earth 84695.58 37,097,098 km
96.5 LD
1956-01-07 Juptr 13057.34 269,366,423 km
701 LD
1944-06-28 Earth 51209.38 16,481,308 km
42.9 LD
1934-11-06 Earth 67629.03 19,389,059 km
50.4 LD
1921-07-02 Earth 49794.68 20,174,502 km
52.5 LD
1911-11-09 Earth 73961.91 25,543,839 km
66.5 LD

Looked up from NASA's NeoWs API and cached — last refreshed 2026-09-04T23:00:20.471619+00:00.