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Asteroid Near-Earth Potentially hazardous

511684

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511684 (2015 BN509)

511684 is an asteroid in the Apollo orbit class. Its orbit takes it from 0.43 AU to 1.58 AU from the Sun; one orbit takes 369 days; it is about 0.32 km across. Discovered 22 January 2015 by Mt. Lemmon Survey. Orbit from the JPL solution of 11 January 2026.

Where is it now

Distance from Sun
1.578 AU
True anomaly
178.31°
Distance from Earth
1.045 AU
As of
3 November 2026

Two-body Kepler propagation — accurate to ~0.1% for major planets over decades, less so for highly-perturbed bodies. Use JPL Horizons for high precision.

Sun Earth — 0.992 AU from the Sun Earth 511684 — 1.578 AU from the Sun 511684
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 511684 is 1.045 AU from Earth today (8.7 light-minutes).

In the sky

Right ascension
08h 04m 11s
Declination
+16° 23′ 05″
Constellation
Cancer
Distance from Earth
1.04 AU
Elongation from the Sun
101.69° — well clear of the Sun

Favours the northern hemisphere; low or below the horizon from far south.

From your location

See how high it is right now, whether it is up after civil twilight, and when it rises and sets where you are.

How do I find my coordinates?

Google Maps on a computer

  1. Right-click the spot where you'll be observing.
  2. The first line of the menu is the coordinates, e.g. 51.50722, -0.12758 — click it and they're copied.
  3. Paste them above.

Google Maps on a phone

  1. Press and hold the spot to drop a pin.
  2. The coordinates appear in the search bar (or on the pin's card) — tap to copy, then paste above.

A full Google Maps link works too, but the short maps.app.goo.gl share links don't carry coordinates — copy the numbers instead. We round to about a kilometre; that's all the sky calculation needs.

Know your what3words address? Paste it, e.g. ///filled.count.soap. This is optional — the three words are sent to what3words to convert them, and we don't store the address or the result.

Your location stays in your browser and is sent only for this calculation. Using a what3words address is optional; if you do, the three words go to what3words to be converted and we don't record them. Set a location first, then you can save an email alert for this object. See our privacy policy.

Two-body approximation, good to about a degree for the planets — enough to find the constellation and know whether it is up.

Orbital elements

Semi-major axis
1.007 AU
Eccentricity
0.5684
Inclination
4.16°
Orbital period
369 days
Perihelion
0.435 AU
Aphelion
1.579 AU
Longitude of ascending node
120.06°
Argument of periapsis
143.22°
Epoch · J2000
2461200.5
Orbit class · APO
Apollo
Earth MOID · 9.6 LD
0.0247 AU
Tisserand (Jupiter)
5.89

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
592
Data arc
20.1 years
First observed
3 December 2005
Last observed
9 January 2026
Residual RMS
0.38 ″
Solution · Otto Matic
11 January 2026

Physical properties

Mean radius
0.16 km
Rotation period
5.67 hours

Visual & observation

Geometric albedo
0.093
Absolute magnitude (H)
20.77

Discovery & classification

Discovered by
Mt. Lemmon Survey
Discovery date
22 January 2015
Discovery site
Mount Lemmon

Also known as 2015 BN509

Apollo Near-Earth Object Potentially Hazardous Asteroid

Close approaches 180 on record

When (UTC) Body Distance Lunar distances Relative speed
2028-04-12 04:06:00 Venus 0.0323 AU 12.6 LD 19.1 km/s
2029-05-10 04:44:00 Mercury 0.042 AU 16.3 LD 23.7 km/s
2029-05-10 04:44:00 Merc 0.042 AU 16.3 LD 23.7 km/s
2033-07-07 12:43:00 Venus 0.0778 AU 30.3 LD 16.9 km/s
2034-05-30 15:17:00 Merc 0.0526 AU 20.5 LD 25.3 km/s
2034-05-30 15:17:00 Mercury 0.0526 AU 20.5 LD 25.3 km/s
2039-06-19 17:07:00 Merc 0.0742 AU 28.9 LD 28 km/s
2039-06-19 17:07:00 Mercury 0.0742 AU 28.9 LD 28 km/s
2042-06-08 03:41:00 Venus 0.0698 AU 27.2 LD 17.3 km/s
2044-07-09 00:04:00 Merc 0.0973 AU 37.9 LD 30.6 km/s

Next ten from today. 1 lunar distance = 384,400 km. Source: JPL close-approach data.

Sources