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Disintegrating exoplanet to provide new clues about planet composition

Astronomers have made observations which can reveal the chemical makeup of a rocky world orbiting a distant star.

Led by researchers at The Open University, in conjunction with the Universities of Warwick and Sheffield, the observations could initiate a new discipline: exogeology – the geology of planets orbiting other stars.

The work focused on the extraordinary exoplanet named ‘KIC 12557548 b’, or ‘KIC 1255 b’ for short.

The researchers predict that dust created by KIC 1255 b’s disintegrates will be measurable, providing evidence for the exoplanet’s composition. The team will attempt to make these first exogeological measurements with further observations in summer 2015.

Commenting on the project’s success to date and its potential Professor Tom Marsh, of the University of Warwick’s Astrophysics Group, said:

"This is an exciting result because in this remarkable system we are seeing a planet torn apart before our eyes allowing us a glimpse of its composition”.

KIC 1255 b’s surface is heated to over 2100K (over 1800°C), hot enough to vapourise rock. The planet’s outer layers are continuously destroyed, with the evaporating rock feeding a cloud of dust. This dust cloud then forms an extended comet-like tail following the planet in its orbit.

To make the observations the researchers used ULTRACAM, an ultra-fast camera on the Science and Technology Facilities Council’s William Herschel Telescope (WHT).

“It is exciting to see the high-speed camera ULTRACAM that Warwick and Sheffield have operated for over a decade being put to this unusual use which we did not dream of when we designed it", said Professor Marsh.

The ULTRACAM measurements, the most sensitive yet made, revealed that the dust cloud blocks a slightly larger fraction of the star’s blue light than red light. A similar effect is seen at sunset on Earth when the Sun’s light is scattered by dust in the Earth’s atmosphere, making the remaining light appear reddened.

The exact colour-dependence of the scattering by dust can reveal the size and composition of the dust grains. Ultimately, a series of measurements of KIC 1255b’s dust cloud could reveal the composition of the dust.

The paper ‘Direct evidence for an evolving dust cloud from the exoplanet KIC12557548 b’ is published in the journal The Astrophysical Journal Letters and was supervised by Dr Carole Haswell, Senior Lecturer in Astrophysics at The Open University.

18 February 2015

Notes for Editors

  • The team used a state-of-the-art, ultra-fast camera, ULTRACAM, on the Science and Technology Facilities Council’s (STFC) William Herschel Telescope (WHT), in La Palma, the Canary Islands. The researchers observed an extraordinary "exoplanet" named "KIC12557548 b" or ‘KIC 1255b’ for short. The planet is similar in size to the planet Mercury in our solar system and far too small to be seen on its own from Earth.
  • The team's paper "Direct evidence for an evolving dust cloud from the exoplanet KIC12557548 b" is published in the journal The Astrophysical Journal Letters.
  • Image provided courtesy of Maciej Szyszko. For Further information please visit:
  • A light year is the distance light would travel in a year: around 5,878,000,000,000 miles. Planet KIC 1255b is 1,500 light years, or 8,817,000,000,000,000 miles, from Earth - that's nearly 9,000 trillion miles away (where a trillion is defined as a million million miles).
  • About Science and Technology Facilities Council (STFC): STFC is keeping the UK at the forefront of international science and tackling some of the most significant challenges facing society such as meeting our future energy needs, monitoring and understanding climate change, and global security. The Council has a broad science portfolio and works with the academic and industrial communities to share its expertise in materials science, space and ground-based astronomy technologies, laser science, microelectronics, wafer scale manufacturing, particle and nuclear physics, alternative energy production, radio communications and radar. STFC is one of seven publicly-funded research councils. It is an independent, non-departmental public body of the Department for Business, Innovation and Skills (BIS). For further information please visit:
  • About ULTRACAM: ULTRACAM is an ultra-fast, triple-beam CCD camera designed to study astrophysics on the fastest timescales. The instrument was designed and built by a consortium including Professor Dhillon from the University of Sheffield, Professor Tom Marsh from the University of Warwick and the Science and Technology Facilities Council (STFC’s) UK Astronomy Technology Centre. It saw first light on the 4.2-m William Herschel Telescope (WHT) on La Palma in 2002, and became the first UK instrument to be mounted on the European Southern Observatory’s (ESO’s) 8.2-m Very Large Telescope (VLT) in Chile. The large quantity of observing time awarded to ULTRACAM (totalling one year of nights over the last decade) on some of the world's largest telescopes is testament to the competitiveness of the science performed with the instrument. ULTRACAM has made a major impact in astronomy: it has produced ground breaking papers covering fields as diverse as outer Solar System objects, extra-solar planets, brown dwarfs, interacting binaries, white dwarfs, black holes and pulsars.


To speak with Professor Marsh or for further information please contact:

Tom Frew – International Press Officer, University of Warwick

a dot t dot frew at warwick dot ac dot uk

024 7657 5910