Disintegrating rocky exoplanet could unlock secrets to how our solar system was formed

February 19, 2015 by Rebecca Wilhelm, Science and Technology Facilities Council
Artist's impression of exoplanet KIC 1255 b as it orbits its parent star followed by a comet-like dust tail. Credit: Maciej Szyszko

Exciting new research by astronomers at The Open University (OU) and the Universities of Warwick and Sheffield has opened up the chance to find out what distant planets are made of. The team of astronomers have made observations which can help reveal the chemical makeup of a small rocky world orbiting a distant star about 1500 light years away from Earth, increasing our understanding of how planets, including ours, were formed.

Using a state-of-the-art, ultra-fast camera, ULTRACAM, on Science and Technology Facilities Council's (STFC) William Herschel Telescope (WHT) the researchers have observed an extraordinary exoplanet named 'KIC 1255 b'. "A single year on KIC 1255b lasts only 16 hours on Earth and the whole planet seems to be slowly boiling away under intense heat of its sun" said Jakub Bochinski, research student at the OU, and lead author of the study. The planet's surface is heated to over 2100K (over 1800°C), hot enough to vapourise rock. As a result, the planet's outer layers are continuously destroyed, with the evaporating rock creating a comet-like dust tail following the planet in its orbit.

Once every orbit, the planet and the dusty tail pass across the host star, blocking some of its from our view. The planet itself is tiny, similar in size to Mercury - far too small to be seen on its own. The dust cloud, however, is much bigger and blocks up to 1% of the star's light each orbit. For comparison, the largest planet in our Solar System, Jupiter, would block 1% of the Sun's light in a similar arrangement. The dust cloud grows and shrinks in size seemingly at random, some of the time disappearing from our view completely. Five nights of the WHT observations show this variation clearly, offering a unique chance to pin down the mechanism responsible for this unusual behaviour.

The ULTRACAM measurements were the most sensitive yet made, and revealed that the dust cloud, when visible, 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 (measured by carrying out simultaneous, multi-colour measurements with ULTRACAM) can reveal the size and composition of the dust grains. Ultimately, a series of measurements of KIC 1255b's could reveal the chemical composition of the dust.

Since the dust is made from the rocky surface of the disintegrating planet, the same technique will allow the of the planet's surface to be measured. The team will attempt to make these first exogeological measurements with further observations in summer 2015. Jakub Bochinski added: "This is an incredibly exciting breakthrough as it opens up the possibility of determining the chemical composition of this rocky planet. By doing that we can find out how typical our solar system is, helping us learn more about how Earth and other were formed."

Explore further: Telescope to seek dust where other Earths may lie

More information: "Direct Evidence for an Evolving Dust Cloud from the Exoplanet KIC 12557548 b." Jakub J. Bochinski et al. 2015 ApJ 800 L21. DOI: 10.1088/2041-8205/800/2/L21

Related Stories

Telescope to seek dust where other Earths may lie

January 22, 2015

The NASA-funded Large Binocular Telescope Interferometer, or LBTI, has completed its first study of dust in the "habitable zone" around a star, opening a new door to finding planets like Earth. Dust is a natural byproduct ...

New milestone in the search for water on distant planets

September 24, 2014

Astronomers have found water vapor in the atmosphere of a planet about four times bigger than Earth, in the constellation Cygnus about 124 light years - or nearly 729 trillion miles - from our home planet. In the quest to ...

250 years of planetary detection in 60 seconds

February 12, 2015

Early astronomers realized some of the "stars" in the sky were planets in our Solar System, and really, only then did we realize Earth is a planet too. Now, we're finding planets around other stars, and thanks to the Kepler ...

Spitzer telescope witnesses asteroid smashup

August 28, 2014

(Phys.org) —NASA's Spitzer Space Telescope has spotted an eruption of dust around a young star, possibly the result of a smashup between large asteroids. This type of collision can eventually lead to the formation of planets.

Recommended for you

Making stars when the universe was half its age

January 18, 2019

The universe is about 13.8 billion years old, and its stars are arguably its most momentous handiwork. Astronomers studying the intricacies of star formation across cosmic time are trying to understand whether stars and the ...

Saturn hasn't always had rings

January 17, 2019

One of the last acts of NASA's Cassini spacecraft before its death plunge into Saturn's hydrogen and helium atmosphere was to coast between the planet and its rings and let them tug it around, essentially acting as a gravity ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.