Astronomers attempt to understand molten rock surface of ‘diamond planet’

According to a May 5 Discovery Online news report,  over a period of two years, a team led by University of Cambridge researchers, noted a three-fold change in temperature on the surface of 55 Cancri e, which is considered a super-Earth planet that orbits a sun-like star 40 light-years away in the constellation of Cancer. It is twice the size of Earth and eight times our planet’s mass.

Using data from NASA’s Spitzer Space Telescope, astronomers have revealed wild atmospheric changes on the well-studied exoplanet – changes that they suspect are driven by extreme volcanic activity. 55 Cancri e is well-known to exoplanet hunters as the “diamond planet” – a world thought to be carbon-rich, possibly covered in hydrocarbons.

Discovery Online reported that a new finding published May 5 in the arXiv pre-print service, has added a new dimension to the 55 Cancri e weird nature.

“This is the first time we’ve seen such drastic changes in light emitted from an exoplanet, which is particularly remarkable for a super-Earth,” said co-author Nikku Madhusudhan, of Cambridge’s Institute of Astronomy, said in a press release. “No signature of thermal emissions or surface activity has ever been detected for any other super-Earth to date.”

“We saw a 300 percent change in the signal coming from this planet, which is the first time we’ve seen such a huge level of variability in an exoplanet,” said lead author Brice-Olivier Demory of the Cambridge’s Cavendish Laboratory. “While we can’t be entirely sure, we think a likely explanation for this variability is large-scale surface activity, possibly volcanism, on the surface is spewing out massive volumes of gas and dust, which sometimes blanket the thermal emission from the planet so it is not seen from Earth.”

Discovery Online reported that the Spitzer Space Telescope measurements of the “day-side” of the exoplanet revealed a temperature swing of 1,800-4,900 degrees Fahrenheit, hinting that the surface of 55 Cancri e is molten and undergoing intense volcanic eruptions as it orbits its star, 55 Cancri. The exoplanet is the innermost world in the 55 Cancri system of five known exoplanets with an extremely compact orbit around the star.

Astronomers say that in our Milky Way Galaxy solar system, they know of one place that is wracked by volcanic activity as it completes its orbit around Jupiter. The moon Io is driven by intense tidal interactions with the solar system’s largest gas giant planet, causing intense volcanic activity that can be seen from Earth. The volcanism on 55 Cancri e, however, is many more times intense than Io’s. This discovery, although preliminary, has thrown a wrench in the previous “diamond planet” model of 55 Cancri e.

“When we first identified this planet, the measurements supported a carbon-rich model,” Madhusudhan told Discovery Online. “But now we’re finding that those measurements are changing in time. The planet could still be carbon rich, but now we’re not so sure – earlier studies of this planet have even suggested that it could be a water world. The present variability is something we’ve never seen anywhere else, so there’s no robust conventional explanation.”

“But that’s the fun in science – clues can come from unexpected quarters. The present observations open a new chapter in our ability to study the conditions on rocky exoplanets using current and upcoming large telescopes,” Madhusudhan added.

According to the Discovery Online report, astronomers suggest that it would be several decades before they would be able to directly image a mega-volcano erupting on a nearby exoplanet like what is happening on 55 Cancri e.

Be social, please share!