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Asteroid Near-Earth

137170

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137170 (1999 HF1)

Where is it now

Distance from Sun
1.134 AU
True anomaly
159.2°
Distance from Earth
2.096 AU
As of
11 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 — 0.998 AU from the Sun Earth 137170 — 1.134 AU from the Sun 137170
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 137170 is 2.096 AU from Earth today (17.4 light-minutes).

In the sky

Right ascension
13h 39m 37s
Declination
+01° 14′ 30″
Constellation
Virgo
Distance from Earth
2.1 AU
Elongation from the Sun
11.36° — too close to the Sun to observe

Visible from both hemispheres.

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
0.819 AU
Eccentricity
0.4625
Inclination
25.66°
Orbital period
270.8 days
Perihelion
0.44 AU
Aphelion
1.198 AU
Longitude of ascending node
155.84°
Argument of periapsis
253.42°
Epoch · J2000
2461200.5
Orbit class · ATE
Aten
Earth MOID · 67.5 LD
0.1735 AU
Tisserand (Jupiter)
6.987

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
8,985
Data arc
27.04 years
First observed
20 April 1999
Last observed
5 May 2026
Residual RMS
0.23 ″
Solution · Otto Matic
6 May 2026

Physical properties

Rotation period
2.32 hours

Visual & observation

Absolute magnitude (H)
14.66
Spectral type (SMASS)
X:

Discovery & classification

Discovered by
LONEOS
Discovery date
20 April 1999
Discovery site
Anderson Mesa

Also known as 1999 HF1

Aten Near-Earth Object

Close approaches 50 on record

Flyby geometry
Ecliptic flyby of 137170 at 2045-03-08 20:35 UTC Top-down view of the ecliptic, Earth at the centre, for the 2045-03-08 20:35 UTC close approach of 137170. Catalogue miss distance 72.7 LD · 2.79 × 10⁷ km. The curve is the geocentric path from 2045-03-05 to 2045-03-11, 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 north of the ecliptic. The path is a geocentric ecliptic ephemeris from JPL Horizons. The inset is a heliocentric view and is approximate. Sun 72.7 LD · 2.79 × 10⁷ km 2045-03-08 20:35 UTC Earth Moon Heliocentric, approximate

Top-down view of the ecliptic, Earth at the centre, for the 2045-03-08 20:35 UTC close approach of 137170. Catalogue miss distance 72.7 LD · 2.79 × 10⁷ km. The curve is the geocentric path from 2045-03-05 to 2045-03-11, 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 north 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
2031-08-15 03:23:00 Venus 0.1449 AU 56.4 LD 23.1 km/s
2032-07-22 21:36:00 Venus 0.1356 AU 52.8 LD 18.1 km/s
2036-04-02 08:28:00 Venus 0.0528 AU 20.6 LD 21.3 km/s
2039-12-14 03:03:00 Venus 0.0924 AU 36.0 LD 25.2 km/s
2045-03-08 20:35:00 Earth 0.1867 AU 72.7 LD 17.1 km/s
2060-07-11 21:18:00 Venus 0.148 AU 57.6 LD 24 km/s
2065-03-01 15:09:00 Venus 0.0731 AU 28.5 LD 20.2 km/s
2065-03-13 22:03:00 Earth 0.1751 AU 68.2 LD 18.9 km/s
2068-11-11 02:14:00 Venus 0.0661 AU 25.7 LD 23.8 km/s
2093-02-23 03:44:00 Venus 0.149 AU 58.0 LD 22.2 km/s

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

Sources