First images of multi-planet system

An international team of astronomers has become the first to capture images of a multi-planet system around a normal star, much like our own solar system.

The images show three planets, each several times larger than Jupiter, orbiting a star known as HR 8799. Faintly visible to the naked eye, the star is 130 light years from the Earth in the constellation of Pegasus. With a mass of 1.5 times that of the Sun, it is intrinsically brighter than the Sun and, at around 60 million years old, significantly younger.

Dr Jennifer Patience of the Astrophysics Group at the University of Exeter and co-author on the paper, said: “We’ve been trying to capture images of extrasolar planets around stars for many years and now we have pictures of three at once. This is an incredibly exciting moment for astronomy and a key step in the journey towards understanding what is out there, beyond our own solar system.”

More than 200 planets orbiting stars other than the Sun have been detected indirectly in the past decade. However, this is the first time that astronomers have been able to capture an image of a system of planets outside our solar system - known as extrasolar planets. The team was led by Dr Christian Marois of the National Research Council of Canada’s Herzberg Institute of Astrophysics.

The team used the giant Gemini-N and Keck and telescopes on Mauna Kea, Hawaii, to capture their infrared images. The telescopes use ‘adaptive optics’ to minimise the blurring effects of the Earth’s atmosphere, producing images with exceptional detail and resolution, exceeding that of the Hubble Space Telescope at these wavelengths.

Professor John Womersley, Director of Science Programmes at the Science and Technology Facilities Council which funds the UK subscription to Gemini, said “As our knowledge of exoplanets improves, we will be able to determine how planets form, what chemistry exists on them and one day, we hope, we may even be able to tell whether planets around other stars support life.”