Discovery of a Planet with the Most Eccentric Orbit at a Distance of 117 Light Years

Scientists have discovered a planet that has the most eccentric orbit ever observed. While the planets of the solar system have nearly circular orbits, there are a few planets with more elliptical orbits, and this exoplanet, named HD 20782, has the most eccentric orbit observed to date. According to the Christian Science Monitor, this planet orbits a star located about 117 light years from Earth. A group of researchers from eight universities and five scientific institutions published the results of this research in February. The mass of this planet is about that of Jupiter, but it orbits its star like a comet. The eccentricity of an orbit is measured on a scale from 0 to 1. An eccentricity of zero indicates a perfectly circular orbit, and as the number approaches one, the orbit resembles a complete ellipse. According to researchers, the planet HD 20782 has an eccentricity of 0.96, moving in a nearly flat ellipse and completing its orbit around its star in 597 days. For comparison, Earth's eccentricity is 0.017, and Mercury has the most eccentric orbit in the solar system with an eccentricity of 0.205, assuming Pluto is no longer considered a planet. Stephen Kane, the lead researcher from San Francisco State University, states, 'The mass of this planet is about that of Jupiter, but it orbits its star like a comet.' The distance of this planet at its farthest point in its orbit from its star is 2.5 times the distance between the Sun and Earth. At its closest point in the orbit, HD 20782 is only 0.06 times the distance from Earth to the Sun from its star, which is closer than the distance of any of the planets in the solar system to the Sun. It is likely that another planet in the same system collided with HD 20782, or something close to a collision occurred that caused that planet to be completely ejected from the central star's orbit and changed the orbit of this planet to its current state. 'Science Daily' also reported that scientists used a space telescope to capture the light characteristics of this planet when it is at its closest position in its orbit to its star. The collected information tells scientists how the atmosphere of a planet like HD 20782 is while it spends most of its time far from its star. According to these researchers, the percentage of light reflected from a planet, and in other words, how bright it appears in the sky, is partly determined by its atmospheric composition. For example, planets like Venus and Jupiter, which are covered with clouds full of ice particles, are very reflective. However, if a planet like Jupiter gets too close to the Sun, the Sun's heat will destroy the icy materials in its surrounding clouds. The Christian Science Monitor writes that it is likely that another planet in the same system collided with HD 20782, or something close to a collision occurred that caused that planet to be completely ejected from the central star's orbit and changed the orbit of this planet to its current state. Another possibility for the strange orbit of this planet is that HD 20782 is actually in a binary star system, and the second star likely caused the path of this planet's movement to stretch from a circular to an unusual elliptical shape.