To learn more about this unusual binary, Best and collaborators began by using observed properties like sky position, proper motion, and radial velocity to estimate the likelihood that 2MASS J—AB is, indeed, a member of the TW Hydrae Association of stars.
Stuart Greenbaum | orchestral works | Symphony No.2 | Double Planet
This allowed Best and collaborators to estimate the masses and effective temperatures of the components from luminosities and evolutionary models. The binary components lie among the faintest and reddest planetary-mass L dwarfs. While the International Astronomical Union considers objects below the minimum mass to fuse deuterium around 13 Jupiter masses to be planets, other definitions vary, depending on factors such as composition, temperature, and formation.
The authors describe the binary as consisting of two planetary-mass objects. The individual masses of the components also place them among the lowest-mass free-floating brown dwarfs known. This system will therefore be a crucial benchmark for tests of evolutionary and atmospheric models for low-mass stars in the future.
William M. Best et al ApJL L4. The atmosphere is divided into about 20 regularly spaced haze layers up to kilometers high, or about 93 miles. Only five natural satellites have been discovered orbiting Pluto.
It is believed that this moon system was formed after a collision with a body similar in size to Pluto, in the early history of the solar system. Charon is the biggest moon of Pluto, followed by four much smaller circumbinary moons: Nix, Styx, Kerberos and Hydra. They were first identified in by astronomer James Christy. The orbit periods of all the moons are linked in a system of orbital resonances and near resonances.
It is named after the ferryman of the dead in Greek mythology. It has about half the diameter of Pluto and also one-eight of its mass, being the biggest known moon of a dwarf planet. Due to its size the gravitational influence is such that the barycenter or the plutonian system lays outside Pluto the same as in the case of the Sun and Jupiter. Charon and Pluto orbit each other once every 6.
They are gravitationally locked to one another. Each keeps the same face towards the other. These molecules are not believed to be native to Charon but rather originated on Pluto and were carried over somehow. Crossing its equator, a massive belt of possible tectonic fracturing indicates that something tried to tear Charon apart.
It is believed that Charon was formed after Pluto suffered a collision with a similar body. The other theory is that Charon collided with Pluto and thus resulted in its current stage. It has a diameter of It was named after the Greek goddess of the night. It is the third moon of Pluto by distance, orbiting between the moons Styx and Kerberos.
The reason for naming it Nix, and the other moon Hydra, was to honor the spacecraft mission New Horizons, the initials N and H.
Earth-Moon: A Watery “Double-Planet”
The reddish area on Nix is most likely due to an impact crater. It is thought to have been formed from debris after Pluto suffered a collision.
It is not tidally locked and tumbles chaotically similar to the other small moons. It completes a rotation in Nix orbits the Pluto-Charon barycenter at a distance of Nix has an orbital period of approximately It is approximately 16 kilometers or 9. It orbits the Pluto-Charon barycenter at a distance of 42, kilometers, putting it between the orbits of Charon and Nix. Styx was both a deity and a river that formed the boundary between Earth and the Underworld in Greek mythology. Kerberos is about 19 kilometers or 12 miles in its longest dimension.
It was the fourth moon to be discovered, and was announced in The double-lobed shape of Kerberos is likely formed by two smaller objects that merged. Like the other small moons it has a chaotic rotation.
Welcome to the double planet
It orbits the Pluto-Charon barycenter at a distance of 57, kilometers or 35, miles. It orbits between Nix and Hydra and makes a complete orbit around Pluto roughly every It was supposed to be called Cerberus but the name was taken, thus the Greek form of the name Kerberos was acceptable to the IAU. Cerberus in Greek mythology was a multi-headed dog that guarded the gates of the underworld. It is the second largest moon of Pluto, with a diameter of about 51 kilometers or 32 miles, slightly bigger than Nix.
They were both discovered in It was named after the nine-headed underworld serpent in Greek mythology. It has a highly reflective surface caused by the presence of water ice, similar to other plutonian moons. Hydra is about 5. The surface spectrum of Hydra is slightly bluish compared to that of Nix. Hydra is the only plutonian moon that completes a rotation in less than a day, making it the fastest.
Hydra has an orbital period of approximately Due to extreme cold temperatures, it seems unlikely that life could exist there. Even if water is present, it is essentially rock-like. Now, the agency is considering the possibility of sending another mission to Pluto, but this one would stay in orbit to study the surface.
Since the last mission was a success, revealing a complex world, it is only natural that further expeditions would be sent there. Pluto Facts Pluto will always be the ninth planet to us!
It was discovered in by Clyde Tombaugh and was classified for 75 years as the ninth planet of the Solar System. Since the beginning of the s, its status as a planet was questioned following the discovery of other objects of similar size.
Pluto is the ninth-largest and tenth most massive known object directly orbiting the Sun. However, when it comes to the trans-Neptunian objects, it is the largest by volume but less massive than Eris. It is named after the Roman god of the underworld, the equivalent of Hades in Greek mythology. It is made primarily out of ice and rock. Like other Kuiper Belt objects, it has an eccentric orbit. The eccentricity is moderate however and the orbit is inclined as it ranges from 30 AU to 49 AU. Charon is the largest with a diameter just over half of Pluto.