Nereid

Nereid is a fascinating moon in our Solar System that has captured the attention of astronomers and space enthusiasts alike. With a Nereid radius of 170 km, making it 37.5× smaller than Earth's size, this celestial body presents unique characteristics that distinguish it from other objects in our cosmic neighborhood. Positioned at an average distance of 5.51e+6 km (0.037 AU) from the Sun, Nereid occupies a significant place in the Solar System's architecture. As a moon, Nereid demonstrates the incredible diversity of natural satellites that orbit larger celestial bodies throughout our Solar System.

The Nereid physical characteristics reveal a world of remarkable dimensions and properties. The Nereid radius measures 170 km, making it 37.5× smaller than Earth's size. The Nereid mass of 3.00e+19 kg represents 199066.7× smaller than Earth's mass, giving this world substantial gravitational influence. The Nereid density of 1 g/cm³ (5.5× smaller than Earth's density) provides clues about its internal composition, while the surface gravity of 0.071 m/s² (138.2× smaller than Earth's gravity) determines how objects behave on its surface. The low density indicates a composition dominated by lighter elements, characteristic of gas giants or icy bodies.

The Nereid orbit reveals fascinating details about its journey around the Sun and its relationship to other Solar System objects. The Nereid orbit has a semimajor axis of 5.51e+6 km (0.037 AU), placing it 27.1× smaller than Earth's distance from the Sun. At its closest approach (perihelion), Nereid comes within 1.37e+6 km of the Sun, while at its farthest point (aphelion), it reaches 9.66e+6 km, creating a 150.2% variation in solar distance. The Nereid orbit is highly elliptical with an eccentricity of 0.751 (45.0× Earth's orbital eccentricity), leading to extreme variations in temperature and solar exposure. The Nereid orbit takes 0.10 hours to complete (87628.4× smaller than Earth's orbital period), defining the length of its year. The orbital inclination of 7.23° indicates how much the Nereid orbit is tilted relative to the Solar System's ecliptic plane. This moderate inclination indicates a typical orbital evolution for objects in this region of the Solar System.

The Nereid rotation and axial orientation provide crucial insights into its daily and seasonal cycles, as well as its orbital dynamics. The Nereid axial tilt of 0° determines the intensity and nature of seasonal variations. With minimal axial tilt, Nereid experiences virtually no seasonal changes, maintaining relatively constant temperatures throughout its year. The orbital orientation parameters reveal additional details about Nereid's position in space. The mean anomaly of 0° indicates the planet's current position in its orbit relative to its perihelion. The argument of periapsis of 0° shows how the orbit's orientation changes over time due to gravitational perturbations. The longitude of ascending node of 0° defines the reference point where the orbit crosses the ecliptic plane.

The Nereid temperature and atmospheric conditions are fundamental to understanding its habitability and environmental characteristics. The Nereid average temperature of 0.0 K (-273.1 °C) (-459.7°F) provides the baseline for understanding its climate. These extremely cold temperatures make Nereid inhospitable to life as we know it, with any atmosphere likely frozen solid on the surface. Compared to Earth's average temperature of 15°C (59°F), Nereid presents a dramatically different thermal environment. Being closer to the Sun than Earth, Nereid receives more intense solar radiation, contributing to its temperature profile. The elliptical orbit creates significant temperature variations throughout the year, with extreme seasonal changes.

The Nereid escape velocity and shape characteristics reveal important details about its gravitational field and rotational dynamics. The Nereid escape velocity of 0 m/s determines how easily objects can break free from its gravitational pull. This relatively low escape velocity means that gases and light molecules can easily escape into space, making it difficult for Nereid to retain a substantial atmosphere. The Nereid flattening of 0.0000% indicates how much the planet's rotation affects its shape. This minimal flattening suggests a nearly spherical shape, indicating either slow rotation or a very rigid internal structure.