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Asteroid

Hermione

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121 Hermione (A872 JA)

Where is it now

Distance from Sun
3.442 AU
True anomaly
264.96°
Distance from Earth
3.949 AU
As of
21 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.

Orbit of Mercury Orbit of Venus Orbit of Mars Sun Earth — 0.995 AU from the Sun Earth Hermione — 3.442 AU from the Sun Hermione
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Hermione is 3.949 AU from Earth today (32.8 light-minutes).

In the sky

Right ascension
17h 21m 15s
Declination
-25° 35′ 58″
Constellation
Ophiuchus
Distance from Earth
3.95 AU
Elongation from the Sun
52.92° — 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
3.458 AU
Eccentricity
0.1244
Inclination
7.57°
Orbital period
6.43 years
Perihelion
3.027 AU
Aphelion
3.888 AU
Longitude of ascending node
72.88°
Argument of periapsis
296.94°
Epoch · J2000
2461200.5
Orbit class · OMB
Outer main-belt asteroid
Earth MOID · 792.5 LD
2.0364 AU
Tisserand (Jupiter)
3.108

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
8,202
Data arc
121.3 years
First observed
16 May 1904
Last observed
27 August 2025
Residual RMS
0.22 ″
Solution · Davide Farnocchia
23 March 2026

Physical properties

Mean radius
105 km
Rotation period
5.55 hours

Visual & observation

Geometric albedo
0.048
Absolute magnitude (H)
7.39
Colour index (B–V)
0.74
Spectral type (SMASS)
Ch
Spectral type (Tholen)
C
Colour index (U–B)
0.43

Discovery & classification

Discovered by
Watson, J. C.
Discovery date
12 May 1872
Discovery site
Ann Arbor

Also known as 121 · A872 JA · 1970 VE

Main-Belt Asteroid Named

Close approaches 21 on record

When (UTC) Body Distance Lunar distances Relative speed
2034-07-26 05:30:00 Juptr 1.9649 AU 764.7 LD 4.5 km/s
2048-05-21 11:46:00 Juptr 1.8209 AU 708.6 LD 4 km/s
2062-05-05 21:46:00 Juptr 1.6654 AU 648.1 LD 2.2 km/s
2076-06-27 14:51:00 Juptr 1.5652 AU 609.1 LD 1.8 km/s
2090-06-24 20:16:00 Juptr 1.6942 AU 659.3 LD 2.8 km/s
2104-05-30 16:55:00 Juptr 1.9363 AU 753.6 LD 3.9 km/s
2118-04-03 04:24:00 Juptr 1.9325 AU 752.1 LD 4.6 km/s
2132-02-03 04:07:00 Juptr 1.7851 AU 694.7 LD 3.6 km/s
2146-02-15 19:45:00 Juptr 1.6403 AU 638.4 LD 1.7 km/s
2160-03-25 12:04:00 Juptr 1.5571 AU 606.0 LD 2.1 km/s

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

Sources