Asclepius
Add to an observing list or journal →4581 Asclepius (1989 FC)
Asclepius is an asteroid in the Apollo orbit class. Its orbit takes it from 0.66 AU to 1.39 AU from the Sun; one orbit takes 377 days. Discovered 31 March 1989 by Holt, H. E., Thomas, N. G.. Orbit from the JPL solution of 16 June 2026.
Where is it now
- Distance from Sun
- 1.367 AU
- True anomaly
- 192.54°
- Distance from Earth
- 2.168 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.
In the sky
- Right ascension
- 16h 31m 30s
- Declination
- -18° 44′ 49″
- Constellation
- Ophiuchus
- Distance from Earth
- 2.17 AU
- Elongation from the Sun
- 27.33° — 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.
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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
- 1.021 AU
- Eccentricity
- 0.3564
- Inclination
- 4.93°
- Orbital period
- 377 days
- Perihelion
- 0.657 AU
- Aphelion
- 1.385 AU
- Longitude of ascending node
- 180.21°
- Argument of periapsis
- 255.46°
- Epoch · J2000
- 2461200.5
- Orbit class · APO
- Apollo
- Earth MOID · 1.5 LD
- 0.0038 AU
- Tisserand (Jupiter)
- 5.92
Orbit quality
Orbit very well determined (uncertainty code 0).
- Observations used
- 424
- Data arc
- 32.05 years
- First observed
- 31 March 1989
- Last observed
- 18 April 2021
- Residual RMS
- 0.47 ″
- Solution · Otto Matic
- 16 June 2026
Physical properties
- Rotation period
- 8.01 hours
Visual & observation
- Absolute magnitude (H)
- 20.74
Discovery & classification
- Discovered by
- Holt, H. E., Thomas, N. G.
- Discovery date
- 31 March 1989
- Discovery site
- Palomar
Also known as 4581 · 1989 FC
Close approaches 74 on record
Top-down view of the ecliptic, Earth at the centre, for the 2043-08-16 01:04 UTC close approach of Asclepius. Catalogue miss distance 52.0 LD · 2 × 10⁷ km. The curve is the geocentric path from 2043-08-13 to 2043-08-19, 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.
| When (UTC) | Body | Distance | Lunar distances | Relative speed |
|---|---|---|---|---|
| 2029-05-02 17:42:00 | Venus | 0.0807 AU | 31.4 LD | 8.3 km/s |
| 2032-07-06 21:09:00 | Venus | 0.0864 AU | 33.6 LD | 10.4 km/s |
| 2043-08-16 01:04:00 | Earth | 0.1335 AU | 52.0 LD | 14.3 km/s |
| 2044-08-24 04:14:00 | Earth | 0.0891 AU | 34.7 LD | 8.5 km/s |
| 2050-03-30 18:45:00 | Earth | 0.1898 AU | 73.9 LD | 6.5 km/s |
| 2051-03-24 08:20:00 | Earth | 0.0123 AU | 4.8 LD | 11 km/s |
| 2052-01-01 11:54:00 | Venus | 0.1418 AU | 55.2 LD | 16.5 km/s |
| 2055-03-04 15:52:00 | Venus | 0.0786 AU | 30.6 LD | 8.2 km/s |
| 2071-09-22 05:58:00 | Venus | 0.0186 AU | 7.2 LD | 9.3 km/s |
| 2072-08-20 06:30:00 | Earth | 0.0567 AU | 22.1 LD | 11.6 km/s |
Next ten from today. 1 lunar distance = 384,400 km. Source: JPL close-approach data.
Sources
- visual properties: JPL SBDB (lookup)
- physical properties: JPL SBDB (lookup)
- orbital elements: JPL SBDB