Exoplanet twice the size of Earth may have similar atmospheric ingredients

Image courtesy: NASA/JPL-Caltech

New Delhi: It is likely that 55 Cancri e, an exoplanet twice the size of Earth, has a thicker atomosphere, albeit with ingredients that could be similar to our home planet's atmosphere, a new study has said.

According to researchers, This mysterious planet's atmosphere could comprise of nitrogen, water and even oxygen – molecules found in our atmosphere, too – but with much higher temperatures throughout.

The planet's density, which is also similar to the Earth, is suggestive of the fact that it is rocky as well.

However, due to the intense heat from its host star and its inability to maintain liquid water, the exoplanet doesn't have the potential to support life, the study said.

"Scientists have been debating whether this planet has an atmosphere like Earth and Venus, or just a rocky core and no atmosphere, like Mercury. The case for an atmosphere is now stronger than ever," said study co-author Renyu Hu, astronomer at NASA's Jet Propulsion Laboratory in Pasadena, California.

The findings are based on data from NASA's Spitzer Space Telescope.

The planet is in such close proximity to its host star that the same side of the planet always faces the star, because of which it has permanent day and night sides.

Some scientists also believe that the planet's surface has flowing lava and its interior is filled with a large amount of diamonds.

Using an improved model of how energy would flow throughout the planet and radiate back into space, the researchers found that the night side of the planet is not as cool as previously thought.

The "cold" side is still quite toasty by Earthly standards, with an average of 1,300 to 1,400 degrees Celsius, and the hot side averages 2,300 degrees Celsius.

The difference between the hot and cold sides would need to be more extreme if there were no atmosphere, the study said.

Spitzer observed 55 Cancri e between June 15 and July 15, 2013, using a camera specially designed for viewing infrared light, which is invisible to human eyes.

Infrared light is an indicator of heat energy. By comparing changes in brightness Spitzer observed to the energy flow models, the researchers realised an atmosphere with volatile materials could best explain the temperatures.

The study has been published in The Astronomical Journal.

(With IANS inputs)