naiad

Water plants of the family Najadaceae (AKA the water nymph or Waternymph family). They are annual aquatic herbs, living in fresh or brackish water, and having thin stems and leaves. They go from stringy (Southern Naiad), to feathery (Slender Naiad).

Southern Naiad (Najas guadalupensis)
Slender Naiad, Common Naiad (Najas flexilis)
Bushy Pondweed (Najas gracillima)
Spiny-leaf Naiad (Najas minor)
???????? (Najas major)
Holly-leaf Naiad (Najas Marina)

The irregularly shaped first moon of Neptune, discovered by Voyager 2 in 1989.

Equatorial radius .............. 29 km
Diameter ....................... 54 km
Mean distance from Neptune ..... 48,000 km
Orbital period ................. 0.294396 days
Mean orbital velocity .......... 11.86 km/sec
Orbital inclination ............ 4.74 degrees
Orbital eccentricity ........... 0.0003
Visual geometric albedo ........ 0.06
Visual magnitude from earth .... 24.7
Mass, mean density, and rotational period are unknown.

The moons of Neptune: Naiad, Thalassa, Despina, Galatea, Larissa, Proteus, Triton, and Nereid.

Naiad is the most recent of Neptune's moons to be discovered, and was named for the mythical nymphs of brooks, springs, and fountains. Neptune's other seven moons are Triton, Nereid, Thalassa, Despina, Galatea, Larissa, and Proteus.

Naiad is a tiny little moon that orbits extremely close to Neptune's surface. It whizzes around the equator once every six hours or so (which is blindingly fast when you consider how large Neptune really is). If you could somehow sit yourself down on Neptune, you would see that Naiad moves so fast that you could actually see it move (unlike our moon, which appears to hang motionless in the sky). Naiad moves in the same direction that Neptune orbits (as do most of Neptune's moons), otherwise it would appear to be moving even faster than it already is.

This particular moon was discovered by the Voyager 2 probe in 1989. Oftentimes moons, planets, and asteroids are mathematically "discovered" before we actually locate them. This was not the case with Naiad, it was simply observed in the Neptune photos that Voyager 2 took. Its small size and proximity to the planet was the main reason it had never been discovered before (it kind of blends in with its suroundings). The Voyager 2 photos show Naiad to be an irregularly shaped rock roughly 33 miles in diameter, with no signs of any geological activity, atmosphere, or any other interesting surface phenomena.

• Equatorial radius 29 km
• Equatorial radius (Earth = 1) 4.5469e-03
• Mean distance from Neptune 48,000 km
• Orbital period 0.294396 days
• Mean orbital velocity 11.86 km/sec
• Orbital eccentricity 0.0003
• Orbital inclination 4.74 degrees
• Visual geometric albedo 0.06
• Magnitude 24.7

Na"iad (?), n. [L. naias, -adis, nais, -idis, a water nymph, Gr , , fr. to flow: cf. F. naiade. Cf. Naid.]

1. Myth.

A water nymph; one of the lower female divinities, fabled to preside over some body of fresh water, as a lake, river, brook, or fountain.

2. Zool.

Any species of a tribe (Naiades) of freshwater bivalves, including Unio, Anodonta, and numerous allied genera; a river mussel.

3. Zool

One of a group of butterflies. See Nymph.

4. Bot.

Any plant of the order Naiadaceae, such as eelgrass, pondweed, etc.

© Webster 1913.