Rasalhague

Rasalhague (derived from the Arabic ra's al-hawaā for "head of the serpent keeper"), also known as Alpha Ophiuchi, is a binary star a little over 48 light years from Sol in the constellation Ophiuchus, formerly Serpentarius. Its main interest for humans is its habitable world of Falak, fittingly named after the serpent from the Arabian One Thousand and One Nights, and its native sapient life.

Falak
Falak is the sole habitable world of Rasalhague, orbiting Alpha Ophiuchi B at a distance a little under 1 AU. It is a lucky thing Falak doesn't orbit Rasalhague A as that star went subgiant long ago, causing dramatic climatic change for Falak, significantly warming it and leading to an explosion of biodiversity and sheer biomass.

Like its host star, Falak rotates quickly on its axis, in this case every six hours. This has given it an oblong shape with noticeably stronger gravity at the poles than at the equator. The quick rotation has concentrated its liquid ocean around the equator and as a rule the higher the latitude the more arid the climate. The poles are so arid they are famous for their white sand dunes composed of gypsum and other evaporite minerals that would dissolve in water. Strong winds circulate around the world almost continually and the weather is violent.

While its mass is almost exactly equal to Earth's, its gravity is 1.5g's due to its high density. This has given it a dense atmosphere that somewhat offsets the intense seasonal variation in temperature (Some regions will experience -20° to 50°over a year). Axial tilt is severe at seventy three degrees, the result of an ancient impact that left a massive crater in the northern hemisphere and may have slowed it rotation somewhat. As a result of its tilt, the equator receives less warmth over the course of a year than the poles do, causing a band of ice to form around it while the poles remain ice-free.

Around the same time as the ancient impact, several minor planets were captured by Falak's orbit, further slowing its rotation. Two have remained in orbit to the present day and by studying their composition it was learned they are related to the ancient impactor. The third and smallest natural satellite is believed to be the newest capture as it is not tidally locked.