I have prepared a small photo album of the present state of the HD 28185 system add-on but since the Celestia Gallery has been down for some time and doesn?€™t appear to be coming back I have to do this in here. And yes it is still being worked on. More so than any of you could imagine. This add-on in its first incarnation was first released to the community back in June 2002. It has been almost three years in the making and I can promise that it is probably the single largest add-on ever undertaken by one person. Although the system contains only six planets it is the moons and other objects that truly make up the add-on. At present count there are 33+ Moons, 550+ Asteroids, and several Rouge bodies such as Comets and small Planetoids.
I am seriously thinking of breaking the Add-on into separate pieces. There would be the main system and than subset add-ons such as the asteroid belt and rouge bodies. This will let the user only use the parts they want without taxing there computer and video card. Of course those who have the computer power and good 128mb or better video card will want to go all the way I hope. So here is a little photo album to give you an idea of were things stand with the textures with some information about each world. BTW look to the bottom for an explanation of the naming scheme I came up with.
Enjoy.
HD 28185
Location:
Constellation: Eridanus
Right Ascension: 04 26 26.3205
Declination: -10 33 02.955
Distance from Sol: 129.03 Light Years
Spectral Type: G5
Apparent Magnitude: 7.8
B-V Color: 0.75
Mass: 0.9 Solar Masses
Radius: 1.05 Solar Radii
Effective Temperature: 5705 Kelvin
Metallicity: 0.24 [Fe/H] 1.73 times Solar
Rotation: 2.5 km/s
Inner Edge of Habitability Zone: 0.51 AU
Outer Edge of Habitability Zone: 1.59 AU
Estimated Stellar Lifespan 13717 million years
Askja - fictional planet
Innermost planet in the system and much like Mercury but closer in size to Mars. Some time in its not so distant past Askja was struck by a fairly large asteroid. The collision created an incredible impact basin that filled with magma and created a maria like feature. The shockwaves from the collision traveled through the planet and out to the opposite side. Here the shockwaves fractures the mantel and crust forming large cracks and dikes. These then fill with magma and were left as dark lines all over the far side of the impact.
Asteroid belt - fictional
Lays in roughly the orbit of what would be Venus in our system. It was created by Erebus?€™ migration into the inner planetary system. Several small proto-planets were in this region and as Erebus migrated they were thrown on a collision course. After they were all but totally destroyed Erebus?€™ continued to perturb there orbits keeping them from reforming into new planets.
Erebus - HD 28185 b - Known Gas Giant Planet
The first exoplanet discovered with a circular orbit within its star's habitable zone. The planet is thought to be a Water Giant. Meaning it is made up of the same material most gas giants are, hydrogen, helium, etc.. But it also is purported to have a great deal water in its atmosphere in the form of clouds of ice crystals. This would give the planet a very white appearance with the occasional outcropping of other more rich colored gases from beneath the white cloud deck.
Erebus did not form in its present day position but much farther out in the system. Possibly as far as 7 AU?€™s, it then started to migrate inward. As it did it disrupted the nice orderly system of planets that orbited HD 28185. Many of them were thrown out into space never to be seen again. Some of the lucky ones were merely put into new orbits.
When Erebus finally reached it present orbit it had all but totally remodeled the inner planetary system. As one of the consequences of this migration many of Erebus?€™ moons were totally changed by collisions and the increase in temperature. Many had gathered up enough new material available from the move into the inner planetary system and have grown to full sized planets in there own right.
Basic Data
Parent Star: HD 28185 (G5)
Discovery Status: Confirmed
Planet Type: Water Giant
Habitability: Planet at Earthlike Temperatures at Mean Orbital Distance
Physical Data
Mass ( M sin i ): 5.6 Jupiters
Periastron Distance: 0.94 AU
Mean Distance: 1 AU
Apastron Distance: 1.06 AU
Orbital Period: 385 Days
Radial Velocity of Star: 168 m/s
Inferred Properties
Average Angular Size of Star: 0.558?°
Planet Appearance: White water ice clouds
Periastron Temp: 260 Kelvin
Mean Temp: 252 Kelvin
Apastron Temp: 245 Kelvin
Hill Sphere: 0.125 AU / 18780000 km
Tidally locked if older than: Orbit too eccentric for 1:1 tidal lock
Calculated Bond Albedo: ~ 0.79
Galeras - fictional moon
A moon the size of Mars that is constantly being tidally stretched by Erebus and its outer moons. There is heavy volcanic activity and the crust is often split to allow magma to flow to the surface. A moon in constant change.
Pavant - fictional moon
Larger than Galeras, Pavant is also tidaly pulled by Erebus and the outer moons but to a much less degree. It is large enough to maintain its own internal heat through radioactive decay. Its surface is largely vast outpourings of basaltic magma and very mountainous regions. There is a substantial atmosphere that is chemically similar to Venus'. It even looks a little like Venus except that its cloud cover isn't nearly as thick.
Kell - fictional moon
Kell is nearly 3/4 the diameter Earth. It has a very dynamic surface that has the earliest signs of true plate tectonics. It has a substantial atmosphere made up of mostly CO2, Methane, and other trace gases. It has large bodies of water on its surface that seem to have very primitive forms life in them. Kell orbits at the edge of Erebus' intense radiation field and this is the only reason life seems to gotten a foothold here. Higher forms of life such as humans would be fried by the amount of radiation on Kell's surface.
Yantarni - fictional moon
Yantarni is the size of Earth. Its surface is wrapped by shallow oceans that cover 85% of its surface. The oceans as well as the landmasses contain a great variety of life forms. Many have parallels to the life forms on Earth. Because Erebus' obliquity is only 10 degrees It and its moons do not have much in the way of seasons. Because of this and its slower rotation than Earth of 32 hours Yantarni receives more solar radiation across its surface and equator. It tends to have a more tropical climate across most of its surface changing to more temperate the farther north or south you go or the higher up in elevation. Most of the continents girdle the equatorial zone. There are only small islands it the arctic regions. Because the surface is covered by more water in area than the Earth, Yantarni atmosphere generates cyclonic storms that can move across the vast oceans for great distances before reaching landfall. And because Yantarni's oceans are warmer than Earths the storms tend to be more powerful. There are areas on several of the landmasses were these storms regularly come ashore and cause damage. The largest continent is actually two continents that have collided to form one. Most of the western continent has subducted under the eastern one. This has given rise the moons highest mountain range. Composed of fold and volcanic peaks it stretches from one end of the continent to the other. On the east side of this mountain range is Yantarni's only desert. Yantarni's similarities to Earth are many but there are also many differences.
Methana - fictional moon
At nearly the size of Yantarni, Methana is also a living breathing world. Methana is almost an opposite to its sister moon. Its surface is nearly 75% covered by landmass. The small oceans and seas on its surface are barely large enough to help keep any plate tectonics active. Methana's surface is covered by vast tropical forests and large open grassland savannas in the inner portions of its continents. The weather while always warm and humid is tempered by the fact that very seldom do severe storms ever form in its seas or oceans. The life forms here are mostly of land living types. The seas and oceans also hold a great variety of life forms which some are very similar to those found on Yantarni. Because of the low level of plate tectonics on Methana there are no very high mountains here. The highest peaks are almost all volcanic in origin. Methena's day is 26 hours long.
Hekla - fictional moon
Hekla is a dry dying world. Because its orbit around Erebus takes it closer to its sun than the other inner moons its temperature swings to the hot side. Then on its swing back around Erebus it reaches farther from its sun that it inner sister moons. Always caught between fire and freeze no life seems to ever have gotten a foothold here. the surface is rough and eroded. But at one time in its past there must have been a much wetter climate. There seems to be evidence that there were vast seas and possibly oceans here at one time, but they have long since disappeared. Most likely evaporating into the atmosphere and then leaking into space. There are signs of some recent volcanic activity but not anything major on this slightly larger than Mars world. This moon appears to be headed in the same direction that Mars took. Although unlike Mars Hekla still has a substantial atmosphere of CO2 and other trace gases, there is really no weather here to speak of. On a very rare occasion the clouds many thicken enough for some rain or snow to fall on the dry surface, it soon evaporates back into the atmosphere.
Kos - fictional moon
Kos is one of the lucky planetesimals that was captured by Erebus instead of being thrown out of the system . It is a rocky cratered barren world without and atmosphere. There is evidence of an active past but no sign of any recent surface activity.
Spurr - fictional moon
The outermost of Erebus' natural moons. Since the migration into the inner planetary system Spurr has lost all of its ices to space through sublimation. What is left is left is the rocky core that has been battered many times by impacts.
Opala - fictional planet
Opala is the next planet out from Erebus but started out in a much different orbit. Opala was another of the lucky planets to survive the migration of Erebus. Erebus threw Opala into a new but fairly eccentric resonate orbit. Most of its small moons were lost as a result of the orbital shift. Opala is a Panthalassic planet. That is that it is a rocky world twice the size of the Earth with a subsurface of water ice and then above that a vast world wide ocean hundreds of kilometer deep. In all this makes the planet about half the diameter of Neptune. There are immense cyclonic storms that girdle both sides of the planets equatorial zone. These storms tend to last for months on end and then they are replaced by new ones as the cycle goes on. Could there be life on such a world?
Elbrus- fictional moon
Elbrus is about the size of our moon and is Opala?€™s sole surviving natural moon. It orbits Opala much closer than our moon does to Earth and as such receives tidal flexing between its parent and the larger outer captured moon. Elbrus surface is constantly be resurfaced every couple of million years. The surface is a dark basalt with areas stained by high concentrations of sulfur. The moon would have a low reflectively point if it were not for its clouds of frozen water crystals.
Arenal - fictional moon
Arenal is almost a twin to Mars in many ways and in fact was a planet unto its own right until Erebus came along. It was yet another casualty do to the migration of Erebus. It was also thrown out of the inner planetary system were it originally had a much warmer orbit. Lucky for Arenal on its outward journey it past close enough to Opala for it to be captured and go into a stable but eccentric orbit. It is a cold arid planet that at one time in its past shows signs everywhere that it was warmer and wetter. Arenal is where Mars was several billion years ago. Most of its water has leeched into space or gone underground. The atmosphere is still thick enough for liquid water to exist on it surface. It is composed mainly of CO2 but there is a oxygen, nitrogen and other trace gases. The atmospheric pressure in the lowest areas of Arenal would be equal to Earth at the 14,000 ft elevation. Humans could walk its surface if properly attired in warn clothes and a small supply of oxygen. There are still some small seas of very saline water on the surface. They lay in at one time were the deepest depths of ancient Arenal's oceans. Arenal was much more advanced than Mars was when it came to geologic activity. There are signs of tectonic activity here. There are the outlines of continental shelves as well as sea floors. Most of these geologic features are buried under large sand dunes that girdle the moon. Some of these dunes tower several kilometers high. There are also vast areas that are covered by a layer of water ice deposited there by the clouds that still swirl in its atmosphere. Snow still falls from time to time on the highest mountains on Arenal. They have started to form glaciers on many of the peaks. In few billion years Areanl will probably look even more like Mars as the last of its water and atmosphere leech away into space. By this time even the ice covered mountains will be bare and the only water will be frozen in to polar caps.
Mayon - fictional planet
Mayon is a gas ball slightly larger than Saturn but about 3/4 it?€™s mass. Its coloring is a striking mix of Jupiter and Saturn put together. It has a very large ring system made up of very reflective ice particles that range in size from pebble to the kilometer range. Mayons one distinct feature is a white storm that seems to always circulate in the same region much like Jupiter great red spot. Mayon has a retinue of 11 major moons.
Progromni - fictional moon
Progromni is slightly smaller than Mars and is covered with a subsurface ocean. Most of the water is frozen into a thick crust but tidal forces have broken the surface up letting fresh water come to the surface. The ice crust moves around much as the continents do on Earth. Some of these ice plates slide under one another and others collide and push up to form rises, scarps, and mountains. This moon is king of water based geologic activity. It also has a substantial atmosphere of CO2, Methane, with some O2 and other trace gases.
Cima - fictional moon
Cima is the outermost major moon of Mayon. It is made up of mostly ice. Its surface is vary bright except were impacts have occurred. The impacts bring up dark carbon rich ice which is darker than the sun bleached ice of the surface. There are signs of very large impacts on its surface.
Danau - fictional planet
Danau is a Neptune size sub-jovian world. Its makeup is very similar to Uranus in many ways. It has five major moons.
Fayal - fictional planet
Fayal is a sub-Neptune size sub-jovian. Its makeup is very similar to Neptune in many ways including looking a great deal like Neptune.
It has four major moons.
Well that takes care of the abbreviated version of the photo album.
Now as to how I came up with the naming convention. There were several forum readers that mentioned to me that I should use names instead of the more strictly scientific method I was using to name the worlds of this system. So I started to think of a naming convention that would work. At first I wanted to use the names of ancient Egyptians cities. But I just wasn?€™t finding enough of them. Than I thought of a mix of ancient Egyptian gods and cities. But several of the names of the Egyptian gods have been used and I wanted something different. So I came up with names of volcanoes on the Earth.
So each planet in the HD 28185 system is named after a volcano here on Earth. Some of the names may sound familiar. Erebus id name of the biggest volcano in Antarctica.
So that is were the names come from. As I get ready to release the add-on there might be a few changes in the names but not on the planets and moons seen here. As far as I am concerned these are written in stone. I hope everyone has enjoyed this peek at HD 28185.
As always any comments are welcome and if there is a world any of you want a better look at just ask and I will post a couple of pictures to give a better idea of what they look like.
Don. Edwards
