A team of international astronomers has discovered a giant lowest-mass exoplanet that revolves around a sun-like star
The planet was imaged using infrared data from the Subaru Telescope in Hawaii. Named GJ 504b, the exoplanet orbits the bright star GJ 504 and is several times the mass of Jupiter.
"If we could travel to this giant planet, we would see a world still glowing from the heat of its formation with a color reminiscent of a dark cherry blossom, a dull magenta," said Michael McElwain, a member of the discovery team at NASA's Goddard Space Flight Center in Greenbelt, Md in a press release. "Our near-infrared camera reveals that its color is much more blue than other imaged planets, which may indicate that its atmosphere has fewer clouds."
GJ 504b orbits GJ 504 at a distance nine times more than the distance Jupiter orbits the Sun. According to projections, the planet lies at a distance of 43.5 AU from its star. Scientists previously believed that planets like Jupiter are formed from gas-rich debris disks that surround a young star. When asteroids and comets collide, they produce a core, which at the attainment of sufficient mass, rapidly attracts gas from the disk to form the planet, through its gravitational pull.
This is known as the core-accretion model and is perfectly applicable for planets as far as Neptune's orbit, which is 30 times Earth's average distance from the sun. However, the same model becomes problematic when applied to planets located further away from the sun.
"This is among the hardest planets to explain in a traditional planet-formation framework," explained team member Markus Janson, a Hubble postdoctoral fellow at Princeton University in New Jersey. "Its discovery implies that we need to seriously consider alternative formation theories, or perhaps to reassess some of the basic assumptions in the core-accretion theory."
After analyzing the planet, researchers found that GJ 504b is about four times more massive than Jupiter and has an effective temperature of about 460 degrees Fahrenheit. The star it orbits is slightly hotter than the Sun and is faintly visible to the naked eye. GJ 504b lies at a distance of approximately 43.5 AU (Astronomical Unit) and the system is an estimated 160 million years old.
