In what can be pegged as one of the most stunning imaging work ever, astronomers have directly imaged four planet system 129 light years away.
Using images taken at the W.M. Keck observatory in Hawaii astronomers have created a composite that shows motions of four planets orbiting the young star HR 8799 located 129 light years away in the constellation of Pegasus. The movie [embedded in this article] doesn’t show the full orbits of the planets around the star and that’s because it would take many years of observations. According to calculations, the innermost planet circles the star in around 40 years, while the one that is farthest from the star takes more than 400 years.
Images of the four-planet system were initially captured by Dr. Christian Marois of the National Research Council of Canada’s Herzberg Institute of Astrophysics. The movie animation was put together by Jason Wang, an astronomy graduate student at the University of California, Berkeley, who is part of the Berkeley arm of the Nexus for Exoplanet System Science (NExSS), a NASA-sponsored group formed to encourage interdisciplinary exoplanet science.
Wang said that the animation is based on eight observations of the planets since 2009. He then used a motion interpolation algorithm to draw the orbit between those points. The planets are quite far from each other, which is to be expected due to their enormous size. Because of those large separations, Wang said astronomers will be watching to see if the system is stable or if some of the planets may be ejected from the system.
Although the first three HR 8799 planets were officially discovered in 2008, researchers learned afterwards that the planets had actually already been observed. The “precovery” had been made in 1998 by the NICMOS instrument on the Hubble Space Telescope, but was teased out only after a newly developed image-processing technique was installed. The forth HR 8799 planet was found after further observations in 2009–2010. That planet orbits inside the first three planets, but is still fifteen times the distance from its sun than Earth to our sun.