Planet:41 Cygnus c

41 Cygnus c, nicknamed Helen after the mythical daughter of Zeus and Leda, is a terrestrial planet located in the 41 Cygnus planetary system. It is the first planet orbiting from its star, and the second to be discovered in the system. It orbits 41 Cygnus at a periapsis (nearest distance) of about 158,400,000 km (99,046,600 mi), and an apoapsis (farthest distance) of about 165,600,000 km (102,899,000 mi).

Geological and Climatic Features
Helen has a mean radius of 7946 km (4937 mi), approximately 20% larger than Earth, with an equatorial surface gravity 1.3x greater. It is a very geologically active planet, with a plate tectonics system and many volcanic craters. Because of its increased geological activity, the landscape of Helen transforms and renews itself often, leaving it with many long mountain ranges, but few to rival Earth’s in height. The planet’s high gravity and dense atmosphere also play a role in keeping its mountains low. The atmospheric pressure at sea level on Helen is about 14x that of Earth. While this is little compared to the crushing extremes at the surface of a planet like Venus, this still has noticeable effects on Helen’s climate. Because the atmosphere consists of 19% carbon dioxide, this couples with the extreme density to produce a severe greenhouse effect that leaves the average surface temperature of Helen at a sweltering 135°F (57°C). The greenhouse effect also makes the surface temperature of the planet almost uniform throughout, even at the poles. Thus, Helen has no polar ice caps, and truly, no ice anywhere on its surface.

In addition, almost all the oceans on Helen have long since dried up, leaving the atmosphere with a concentration of water vapor four times higher than that of Earth’s. The rest, about 52% of the water on Helen, is locked inside underground aquifers just below the surface. The only body of water on the planet larger than a small lake is the so-called "Last Ocean", about the size of South America. The result of Helen's large concentration of water vapor coupled with the extreme heat is that the planet has many clouds, but receives little rainfall. In fact, with the exception of the lush marsh-forests surrounding the Last Ocean, rain falls somewhere on Helen only once every month or so. Considering the size of the planet, this means that some places can go without any rain for decades. However, oftentimes rain evaporates before it even reaches the surface of the planet, meaning that it actually rains more frequently than what is experienced on the ground. When it does rain on the surface of the planet, it can be very heavy indeed, and is occasionally accompanied by intense thunderstorms. These rainstorms can last for up to four days straight, traveling miles as they precipitate. Because of the extreme lack of water on Helen, 55% of the planet's surface is stony desert land, much of which does not receive rainfall for centuries, and is completely uninhabitable save for a small number of extremophile species.

The planet has an orbital period of 423 days, but its very slight axial tilt, along with the aforementioned homogenizing effect of its dense atmosphere, does not allow for much variation between seasons. Thus, the hemispheres remain exactly the same all year-round. In addition, a day on Helen is a little more than 19 hours.