Ator Solar System

The known major planets of Ator are, in order from Ator: Maladek, Hemar, Isabeq, Nevea, and Kruth.

Inner System

Maladek is a gas giant of the Hepaestus class, orbiting Ator approximately every seven days, only six million miles above Ator's incandescent surface. The solar flux on Maladek is nearly 200 times as great as on Erona. Maladek keeps one face always toward Ator, but superheated jet streams race around the planet, ensuring that there is no significant temperature difference between the light side of Maladek and the dark side.

The diameter of Maladek is more than one seventh that of Ator, greater than that of Jupiter despite its smaller mass. This is the effect of insolation from nearby Ator. During its frequent transits, Maladek can be seen as a moving black dot on the surface of Ator. Maladek has no moon. Despite its size, Maladek is hidden from view by the brilliance of the sun Ator.

When Ator is covered by Nevea during the Darkening, Maladek's red tortured face can sometimes be seen -- Maladek's apparent diameter is about 4 minutes of arc, allowing its phases to be seen with the naked eye. When at greatest elongation from Ator it is in a half phase; at other times it can be seen as crescent or gibbous. Maladek is the sole known planet of the Inner System.

Middle System

The Middle System consists of Hemar, Isabeq, Nevea, and Kruth. There is a large gap between the Inner and Middle Systems, and another between the Middle and Outer Systems.The first gap contains some asteroid-sized bodies, while the second gap contains many more, some of which are of considerable size, in the range of hundreds of miles in diameter. There are a few "rogue" asteroids (such as Eros or Icarus in our Solar System) which appear to have unstable orbits, sometimes crossing the orbits of the planets.

Nevea's mass is so great that it controls the orbits of Hemar, Isabeq, and Kruth, plus countless smaller bodies. No body can remain in the Middle System unless it is gravitationally locked to Nevea in some way.

Hemar, a rocky red planet, is locked into an orbit that has a 2:1 resonance with Nevea. That means that each revolution of Nevea corresponds to two of Hemar. Hemar has no known moons.

Isabeq, a green gas giant of the Uranus class, is locked into 3:2 orbital resonance with Nevea. That means that three periods of Isabeq equal two of Nevea. The two largest moons of Isabeq can be seen with the naked eye from Krythar. Isabeq's apparent diameter varies, but can be as much as two minutes of arc, at which time the sharp of eye see it as a tiny crescent.

Nevea and its Moons

Nevea is a supergiant planet of the Fafnir class, with a mass almost nine times that of Jupiter, yet approximately the same diameter. It spins very rapidly on its axis and has a system of close to a thousand dark faint rings,concentric circles of particles in orbit around Nevea's equator. The rings are extremely difficult to see. The overall color of Nevea is blue. Its main feature is the system of bands parallel to its equator, always seen at an angle from Gordovia.

Nevea's surface gravity is more than 23 times that of the Earth, causing its atmosphere to diminish rapidly with altitude. In fact, a spacecraft could orbit Nevea in the near-vacuum just a few miles above the cloud tops.

In Gordovia's sky, Nevea is near the horizon, with its bands oriented at an angle. The rotation is visible, as clouds and spots race across the visible surface. Nevea's surface gravity is so great that even its rapid rotation is unable to create a noticeable equatorial bulge, so Nevea's profile is nearly circular.

In Gordovia's sky, Nevea is always in the same place in the sky, since its its stupendous tidal power long ago forced Erona, as well as its other nearer satellites, to keep the same face toward their primary. (Nevea has some very distant satellites that do not follow this rule.)

Nevea can never be seen from the West Face of Erona. Along the boundary of the East Face, Nevea is always on the horizon. Nevea eclipses Ator every day near the vernal equinox, and also every day near the autumnal equinox. During the Summer, Ator passes North of Nevea each day, during the Winter,South of Nevea. The brief interval when Ator is eclipsed by Nevea is called the Darkening,and that is the darkest time in Krythar. The duration of the Darkening varies, but is never more than about three quarters of an Erona hour, due to Nevea's apparent diameter of 11.8 degrees, roughly 23 times the apparent diameter of the Moon as seen from the Earth.

During the Darkening, Nevea's visible face is black, outlined by a thin red circle, the effect of refraction of sunlight in Nevea's thin atmosphere.The rings are seen edge on from Erona, but since Gordovia is substantially North of the equator, it looks "down" on the rings at a very small angle. To the extent that they can be seen at all, the rings look like thin spikes projecting from Nevea's equator. From Gordovia, the spikes project from the upper right and lower left limbs of Nevea, i.e., Nevea appears to be leaning to the left at an angle, which varies depending on the location ofthe observer.

In Northern Gordovia, the angle is about 45 degrees, while in the far South (near the Sea in the Middle of the World), it is around 60 degrees, that is, the bands and rings are closer to vertical than horizontal. In fact in principle, if you can see Nevea, you can determine your exact location by measuring Nevea's altitude and attitude. Nevea's attitude can be measured most easily by the cloud bands, which are clearly visible unless Nevea is in a thin crescent phase. Nevea's phases change with a period of a day.

At sunrise in Gordovia, Nevea is a thin crescent. As Ator climbs in the sky, the crescent changes direction, then grows to be almost full by sunset. Shortly after sunset, Nevea is full, and sheds so much light that the night is not really dark.As the night progresses, Nevea wanes to a thin crescent, and the night is darkest just before the dawn.

The Darkening only occurs near the equinoxes. It is the best time to observe most astronomical objects, as it is darker than night.

Nevea has a number of known moons. The major ones are Erbalt, Erona, Alene, and Medea, in that order from Nevea.

Erbalt, a moon of the Io class, is somewhat smaller than Earth's moon, is dry and volcanically active. The best time to sight Erbalt is during the night when Nevea is in a crescent phase, and Erbalt can be seen as a smaller crescent racing across the darkened portion of Nevea. Erbalt's volcanos and lava lakes can be clearly seen from Gordovia when Erbalt is closest to Erona during the Darkening.

Alene is believed habitable because continents, oceans, and glaciers can clearly be seen from Krythar.

Medea appears blue and has no permanent surface features, although a pattern of white cloudy formations is usually visible.

The rapid sweep of Nevea's stupendous magnetic field through space powers vast electrical storms in the thin ion cloud which always surrounds Nevea, continually replenished by Erbalt's volcanos. Enormous bolts of electricity, thousands of miles in length, continually strike Erbalt, and occasionally strike Erona or Alene. When they strike Erona, they always hit Mount Zardeq,the location of Erona's North magnetic pole.

During the Darkening, this "space lightning" can sometimes clearly be seen from Gordovia. It resembles the Aurora rather than ordinary lightning,and makes no sound, but has colors and shapes and turns on and off unpredictably. When it hits Mount Zardeq, the sky seems like daylight for a few seconds, then turns off abruptly.

On Erona, the side facing Nevea is called the East Face, and the point closest to Nevea is called the East Pole. The direction toward Nevea is called "East" regardless of one's location in Gordovia, and it differs from true East only slightly, more the farther East you are in Gordovia, very little on the West Coast of Gordovia.

One Erona day is basically one revolution of Erona around Nevea. An Erona day is 1.218 Earth days, or approximately 29.23 Earth hours. Erona's year is the same as Nevea's year (and, for that matter, Alene's year) and is approximately 320 Erona days (about 390 Earth days), Nevea's equator, and the orbits of its inner moons, are inclined 25 degrees to the orbit of Nevea, giving Krythar seasons.

Alene is totally occulted by Nevea every 31.4 hours, that is, it moves behind Nevea as seen from Krythar. There are exactly two occultations of Erbalt for every one occultation of Alene. Erbalt is occulted at the same time Alene is occulted, and once again when Alene is at opposition.

As Erbalt races around Nevea, it is seen to transit across the face of Nevea every 15.7 hours. As seen from Krythar, Erbalt rises in the East, transits the face of Nevea, rises in the sky, then moves down, all the time shrinking in apparent size, passing behind Nevea and then finally setting in the East. Alene rises in the East, passes behind Nevea, then crosses the sky, setting in the West, all the time growing in apparent size.

Ator can be totally eclipsed by either Erbalt or Alene, but both of these events are quite rare and occur only near the equinoxes. Erbalt is totally eclipsed by Nevea frequently, Alene somewhat less frequently. A total eclipse of Medea is a rather rare event, visible from Krythar only once in several years.

At its largest, Erbalt appears roughly the same size as the Moon does from the Earth. When furthest away, it appears roughly a third that size. At its largest, Alene appears somewhat larger than the Moon does from Earth. When furthest away, it appears roughly half the size as the Moon does from the Earth. From Gordovia, Erbalt rises and sets in the East, and never goes near the Western horizon. Alene rises in the East and sets in the West, as do Ator and most other objects in Krythar's sky.

As seen from Krythar, Nevea is full just after sunset, and slowly shrinks to a thin crescent just before dawn. During the day, Nevea waxes back to nearly full. Erbalt changes phases irregularly, being full roughly at the same time as Nevea. Alene is full approximately once every 4.2 days. The light from Nevea ensures that it is never truly dark at night in Krythar. On the West Face, nights are dark, especially when Alene and Medea are not in the sky. No part of Gordovia extends into the West face.

Medea orbits Nevea at a considerably greater distance than Alene, and its period resonates with that of Nevea, so that Medea goes through its phases exactly twelve times each year. Medea's apparent size varies only slightly, and is roughly the same as the Moon as seen from the Earth. Medea is a small blue giant of the Neptune class, with white clouds.

Ator causes twice daily small tides on Erona, as does Medea. Alene and Erbalt have variable tidal influence according to rather different schedules. At maximum, Erbalt has about the same tidal influence as the Moon does on the Earth, while at its maximum, the influence of Alene is somewhat greater. The tides exerted by Alene have a cycle of 31.4 hours, those of Erbalt15.7 hours, those by Ator 12 hours, and those by Medea approximately 12.5 hours. The tidal influence of Ator and Medea are each roughly that of the Sun on the Earth, that is, considerably less than the Moon's.

Like all supergiant planets, Nevea has a warm surface, caused by the flow of heat from the interior. For that reason, the East Face of Erona is warmer than the West Face. This is not significant in Gordovia, since Nevea is on the horizon.

The Middle System also contains smaller bodies gravitationally locked to Nevea. The most prominent of these are the L4 and L5 families, which orbit Ator in 1:1 resonance with Nevea, 60 degrees East or 60 degrees West of Nevea. None of these bodies are visible to the naked eye in Gordovia.

Outer System

Remote Zardeq orbits Ator in approximately 30 years. A gas giant of the Saturn class, it has bright icy rings and many moons.

Zardeq is accompanied by its distant companion, Oculus, an ice giant planet of the Ymir class. Oculus has its own independent system of moons.

There are thousands of smaller bodies in the Outer System as well, but none besides Zardeq (and Oculus, for the sharp-eyed) is visible to the naked eye in Gordovia.

For serious stargazing, an observer would have to travel to the West face of Erona to avoid Nevea's persistent glare, and then wait for a time when neither Medea nor Alene is in the sky. However, the brightest stars can be seen during the Darkening, and even during the never-dark Krythar night.

Galactic Cluster

The Ator system is located in a galactic cluster of the M67 class. All its stars are the same age, except for the anomalous "blue stragglers,"(whose existence is unexplained). The cluster is also host to a few stars which are just "passing through" and do not actually belong to the cluster.

With those rare exceptions, there are no stars, other than white dwarfs,of spectral classes O, B, or A; almost all the main sequence stars of the cluster have spectral classes G, K, or M. Because of its age, the cluster has no supergiant stars. The center of the cluster, merely fifteen lightyears from Ator, is easily noted in the sky as a heavy concentration of mostly red giants.

Special thanks to Lawrence L. Larmore, Phd for help on this page.