Menu

Metis — Asteroid in Aquarius

Magnitude 6.3m Asteroid Aquarius Visible
Star Map 3D Solar System
+ List + Plan

About Metis

Description

Metis is an S-type asteroid with a diameter of 173 km, orbiting at 2.39 AU in the asteroid belt. It is composed of silicates and metallic nickel-iron, and may be the exposed core remnant of a larger asteroid that was destroyed by a catastrophic collision early in the solar system's history. Metis has a moderately dark surface (albedo 0.18) and shows spectral similarities with asteroid 113 Amalthea, suggesting they may be remnants of the same ancient parent body — fragments of an old dynamical family. Metis contains under 0.5% of the asteroid belt's total mass and has a relatively fast rotation period of just over 5 hours.

Observing Tips

Metis can reach magnitude 6.3 at the most favorable oppositions, making it one of the brighter asteroids and visible in binoculars. More typically it shines between magnitude 7 and 9. Its inner-belt orbit means it moves at a moderate pace against the star background. Track its nightly motion over two to three nights using a finder chart to confirm its identity. Metis passes through the zodiacal constellations and is best viewed around opposition months, typically March through May. A go-to telescope makes locating it straightforward, though it is bright enough for manual star-hopping.

History

Metis was discovered on April 25, 1848 by Irish astronomer Andrew Graham at Markree Observatory in County Sligo, Ireland — the only asteroid ever discovered from Irish soil. It was the ninth asteroid discovered and was named after Metis, the Titaness of wisdom and cunning in Greek mythology, who was the first wife of Zeus. Markree Observatory was one of the most well-equipped private observatories of the 19th century. No spacecraft has visited Metis, and most of what we know comes from ground-based photometry and spectroscopy.

Fun Facts

Metis holds the distinction of being the only asteroid discovered from Ireland. Its fast 5-hour rotation rate is unusual for its size — most asteroids this large rotate more slowly. If Metis is indeed an exposed metallic core, it provides a rare opportunity to study the interior composition of a differentiated body without needing to dig hundreds of kilometers beneath a rocky crust, as one would have to do on Earth.

Properties

Magnitude 6.33
Type: Asteroid
Distance: 2.387 AU
Orbital Period: 1346.7 days
Diameter: 173 km
Composed of silicates and metallic nickel-iron, may be core remnant of a large asteroid destroyed by collision, estimated to contain under 0.5% of asteroid belt mass, spectral similarities with 113 Amalthea suggest possible remnants of an old dynamical family.

Position & Identifiers

RA 22h 53m 57.5s
Dec -13° 51' 01.9"
Constellation Aquarius
Catalog Metis

Physical Properties

Diameter 173 km
Mass 8.0e18 kg
Albedo 0.18 (18% reflected)
Rotation 5.1 hours
Angular Size 0.1″ (current)

Orbital Properties

Semi-major Axis 2.3864 AU (357.0 million km)
Eccentricity 0.1226
Inclination 5.58°
Orbital Period 3.69 years
Distance 2.033 AU (16.9 light-min)
Elongation 104.9° Good

Brightness Forecast (next 12 months)

Apparent magnitude as Earth–asteroid distance changes through the year. The peak marks the brightest moment in the window — usually around opposition, when the asteroid is closest and fully illuminated.

9.010.0JulAugSepOctNovDecJanFebMarAprMayJunpeak 8.9 · 3 SepnowMagnitude↑ brighter

Computed from JPL orbital elements via m = H + 5·log10(r·Δ). Phase-function correction is omitted, so curves trace distance variation only — accurate within a few tenths for main-belt asteroids; coarse for fast-moving NEOs near Earth.

Observing Tips

Best Months March , April , May
Visibility Telescope
Where to Look Asteroid belt, varies by constellation at opposition
Notes Composed of silicates and metallic nickel-iron, may be core remnant of a large asteroid destroyed by collision, estimated to contain under 0.5% of asteroid belt mass, spectral similarities with 113 Amalthea suggest possible remnants of an old dynamical family.

Discovery

Discovered by Andrew Graham
Date 25 April 1848

Current Ephemeris

2.033
AU from Earth
304.2M
km
0.1
Angular Size
105°
Elongation

How easy to spot?

Sign in and configure your equipment and default location to see a personalized row.
Telescope Bortle 3 Bortle 4 Bortle 5
80mm refr. Easy Easy Easy
150mm Newt. Easy Easy Easy
C8 203mm Easy Easy Easy
Easy Medium Hard Very hard Impossible

Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs

Easy on Seestar S50

Visibility

Set a location in User Settings to see visibility data.

Community Photos (1)

Rendered preview of Metis from the Nightbase orrery, lit from the current Sun direction with the terminator visible.

Rendered preview of Metis from the Nightbase orrery, lit from the current Sun direction with the terminator visible.

Credit: Nightbase orrery render.

Skybred Apr 27, 2026

}