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Asteroid Near-Earth Potentially hazardous

252399

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252399 (2001 TX44)

Where is it now

Distance from Sun
0.93 AU
True anomaly
128.46°
Distance from Earth
1.053 AU
As of
20 October 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 — 0.996 AU from the Sun Earth 252399 — 0.93 AU from the Sun 252399
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 252399 is 1.053 AU from Earth today (8.8 light-minutes).

In the sky

Right ascension
17h 12m 47s
Declination
-36° 23′ 12″
Constellation
Scorpius
Distance from Earth
1.05 AU
Elongation from the Sun
53.95° — near the Sun — look low at dusk or dawn

Favours the southern hemisphere; low or below the horizon from far north.

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
0.875 AU
Eccentricity
0.5459
Inclination
15.21°
Orbital period
298.9 days
Perihelion
0.397 AU
Aphelion
1.352 AU
Longitude of ascending node
57.76°
Argument of periapsis
136.04°
Epoch · J2000
2461200.5
Orbit class · ATE
Aten
Earth MOID · 3.5 LD
0.009 AU
Tisserand (Jupiter)
6.611

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
351
Data arc
22.22 years
First observed
19 September 2001
Last observed
9 December 2023
Residual RMS
0.59 ″
Solution · Otto Matic
8 March 2024

Physical properties

Mean radius
0.15 km

Visual & observation

Geometric albedo
0.478
Absolute magnitude (H)
19.41

Discovery & classification

Discovered by
LINEAR
Discovery date
11 October 2001
Discovery site
Socorro

Also known as 2001 TX44

Aten Near-Earth Object Potentially Hazardous Asteroid

Close approaches 306 on record

Flyby geometry
Ecliptic flyby of 252399 at 2027-08-20 00:15 UTC Top-down view of the ecliptic, Earth at the centre, for the 2027-08-20 00:15 UTC close approach of 252399. Catalogue miss distance 103.3 LD · 3.97 × 10⁷ km. The curve is the geocentric path from 2027-08-17 to 2027-08-23, with a mark at UTC midnights and an arrow for the direction of motion. The circle is the Moon’s mean orbit; the Moon is plotted at closest approach. A ray shows the Sun’s direction. The labelled distance is the full separation. The drawn radius is the part that lies in the ecliptic plane. At closest approach the object is south of the ecliptic. The path is a geocentric ecliptic ephemeris from JPL Horizons. The inset is a heliocentric view and is approximate. Sun 103.3 LD · 3.97 × 10⁷ km 2027-08-20 00:15 UTC Earth Moon Heliocentric, approximate

Top-down view of the ecliptic, Earth at the centre, for the 2027-08-20 00:15 UTC close approach of 252399. Catalogue miss distance 103.3 LD · 3.97 × 10⁷ km. The curve is the geocentric path from 2027-08-17 to 2027-08-23, with a mark at UTC midnights and an arrow for the direction of motion. The circle is the Moon’s mean orbit; the Moon is plotted at closest approach. A ray shows the Sun’s direction. The labelled distance is the full separation. The drawn radius is the part that lies in the ecliptic plane. At closest approach the object is south of the ecliptic. The path is a geocentric ecliptic ephemeris from JPL Horizons. The inset is a heliocentric view and is approximate.

JPL Horizons

When (UTC) Body Distance Lunar distances Relative speed
2027-08-20 00:15:00 Earth 0.2656 AU 103.3 LD 16.4 km/s
2028-11-13 19:38:00 Earth 0.2465 AU 95.9 LD 13.1 km/s
2029-02-21 06:36:00 Merc 0.0195 AU 7.6 LD 21.7 km/s
2029-02-21 06:36:00 Mercury 0.0195 AU 7.6 LD 21.7 km/s
2032-09-30 20:06:00 Earth 0.4151 AU 161.6 LD 13.2 km/s
2033-03-26 00:09:00 Merc 0.003 AU 1.2 LD 20 km/s
2033-03-26 00:09:00 Mercury 0.003 AU 1.2 LD 20 km/s
2033-11-14 08:37:00 Earth 0.2477 AU 96.4 LD 24.9 km/s
2036-08-19 20:51:00 Earth 0.2659 AU 103.5 LD 16.9 km/s
2037-04-28 17:45:00 Merc 0.0048 AU 1.9 LD 19.4 km/s

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

Sources