---
title: "Surtara"
type: "celestial"
authors: [alemannia, nichirin]
navbox: "site"
ooc: true
infobox: (23 rows)
---
**Surtara** is the second planet in the [[ignis-system|Ignis system]], orbiting Ignis Prime and Umbra Magna at a distance of 0.8254 astronomical units every 274 sidereal days. The planet's surface is characterized by vast seas of dunes, rocky table mountains, and eroded highlands. With a radius of 6,052 kilometers, it is about 95% the size of [[avium]] and is a dense terrestrial planet with a thick atmosphere, a warm climate, and a harsh, arid landscape. Its orange-gold color and high reflectivity make it one of the brightest objects in the night sky of the Ignis system when viewed from Avium, reaching an apparent magnitude of -7.51.
## Nomenclature
The planet's name, Surtara, comes from *Surtr*, a figure in Thulean mythology depicted as a giant wreathed in flames who brings about the burning of worlds. The name was chosen in 1424 by the Skjarnish astronomer Håkan Jäderholm, inspired by the planet’s bright orange-gold hue, high reflectivity, and inferred arid environment.
## History
Surtara has been visible to the naked eye on Avium since antiquity, its brilliance earning it a place in early mythologies and navigation systems. Records from several ancient cultures describe its distinctive orange-gold color and regular appearances in the evening or morning sky, and it was often associated with deities or symbols of fire and heat. Early astronomers frequently classified it as a “wandering star” due to its shifting brightness and relatively rapid motion across the background of fixed stars, a characteristic that allowed it to be used for seasonal timekeeping and maritime navigation.
The first telescopic observations of Surtara in the early modern period revealed a small, bright disk, but no surface detail could be discerned due to atmospheric distortion. Photographs taken during its opposition at the end of the 19th century showed faint markings on its disk, including dark streaks and lighter areas that appeared to change subtly over time, possibly due to cloud formations or other atmospheric disturbances. Advances in spectroscopy during the late 1910s allowed for analysis of its atmosphere, revealing that it was composed primarily of nitrogen with measurable traces of carbon dioxide.
## Characteristics
### Physical Properties
Surtara has an average density of 5.24 g/cm³, indicating a composition consisting mainly of silicate rock and a significant metallic core. It has a radius of approximately 6,052 kilometers, corresponding to a surface area of about 4.6 × 10⁸ square kilometers and a volume of 9.31 × 10¹¹ cubic kilometers. Surtara’s mass is estimated at 4.87 × 10²⁴ kilograms, and with a surface gravity of 8.87 m/s², it exerts slightly less gravitational force than Avium.
The planet’s relatively high albedo of 0.38 contributes to its brightness when viewed from Avium. Its average surface temperature is 316.5 K (43.3 °C), with cooler regions reaching 286.5 K (13.3 °C) and low-latitude deserts reaching 346.5 K (73.3 °C). Its effective temperature is 283.5 K (10.3 °C).
### Surface Conditions
Surtara's atmosphere is a nitrogen-carbon dioxide mixture at a surface pressure of approximately 80 kPa. The bulk composition by volume is: 78% nitrogen, 15% carbon dioxide, 3% argon, 2% oxygen, 1% water vapor, and 1% trace gases. Sunlight scattering gives the sky a pale orange hue, while the dense carbon dioxide content drives a strong greenhouse effect, maintaining surface temperatures well above the planet’s effective temperature. Atmospheric circulation, influenced by Surtara’s axial tilt and rotation period, produces regional wind patterns that move dune fields, and occasional thin clouds form from trace water vapor. The composition and pressure also moderate temperature fluctuations between day and night, although extremes persist during long nights.
Surtara’s surface gravity is approximately 8.87 m/s². The planet likely has a weak magnetic field generated by its metallic core that partially shields the atmosphere from Ignian wind erosion and supports long-term atmospheric retention. Combined with frequent dust storms and the planet's carbon dioxide-rich atmosphere, this field contributes to surface chemical weathering, including oxidation and acid-sulfate reactions that produce the planet’s characteristic orange-gold coloration.
### Geology
Surtara’s landscape is dominated by vast dune seas stretching hundreds of kilometers, interrupted by rugged mountain ridges, rocky highlands, and deep gorges formed by ancient rivers. Salt flats and mineral-rich basins mark the locations of ancient lakes, while occasional planetary dust storms reshape the surface. Erosion patterns and sediment deposits indicate that liquid water was more abundant in the past, likely during an earlier climate phase with higher atmospheric greenhouse gas levels and increased volcanic activity. Today, surface water appears only briefly before rapidly evaporating or sublimating due to the planet’s intense heat and low humidity.
Local dune fields exhibit complex morphologies, including transverse, barchan, and star dunes, shaped by prevailing wind directions and local topography. Mountain ridges are primarily composed of volcanic and metamorphic rock, indicating that the planet was geologically active at one point. Gorges display varying widths and depths, with some reaching several hundred meters in depth, indicating significant erosional forces in the past. Salt flats contain diverse mineral assemblages, dominated by sulfates and chlorides, formed through evaporative concentration. Dust storms can sometimes cause surface abrasion and dust redistribution, influencing soil composition and atmospheric opacity.
A massive, concentrated network of mountains known as the Surtaran Alps spans across part of the planet's equatorial region, featuring sharply peaked volcanic cones, folded metamorphic formations, and deep fault-bounded valleys. It is the most geologically active region on Surtara, with evidence of relatively recent volcanic deposits and tectonic uplift. The rugged terrain also significantly influences local climate patterns, creating rainshadow effects that enhance the surrounding aridity and affect wind flow across adjacent dune fields.
### Orbit and Rotation
Surtara orbits Ignis Prime at a semi-major axis of 0.8254 AU, completing a sidereal orbit in approximately 274 days with an average orbital speed of 32.8 kilometers per second. The planet has a sidereal rotation period of 72 hours and a synodic day lasting 73 hours, rotating relatively slowly compared to Avium.
Its axial tilt of 15° produces mild seasonal variations, influencing regional wind patterns and temperature differences across the planet.
### Observation
Surtara has an apparent magnitude of -7.51, making it the brightest planet in the Ignis system as seen from Avium. Its brightness results from a combination of its high albedo and relatively large size. Its absolute magnitude, measured relative to the illumination from Ignis Prime, is -3.72, corresponding to its strong reflectivity and intrinsic luminosity compared to other terrestrial bodies in the system. Although not as close to Ignis Prime as [[hephae]], observations still require techniques to account for stellar brightness when conducting detailed studies.
