NASA detects signs of water on a distant Neptune-sized planet

NASA scientists have detected “a strong water signature” in the atmosphere of a distant Neptune-sized planet called HAT-P-26b.

The study conducted using NASA’s Hubble and Spitzer space telescopes show that the distant planet has a primitive atmosphere composed almost entirely of hydrogen and helium. Although it is not a water world, its atmosphere which is relatively clear of clouds has a strong water signature.

Key Highlights

• The planet, which is popularly known as ‘warm Neptune’ is located about 437 light-years away and orbits a star roughly twice as old as our Sun.

• The study is one of the most detailed studies to date conducted on a planet that is roughly the same size as Neptune and close to its star.

• Researchers detected the presence of water by pooling data obtained from four transits when the planet passed in front of its host star.

• Researchers come up with the chemical composition of the atmosphere by studying how the signatures of the starlight change.

• The water measured in the planet is one of the best measurement of water to date found on an exoplanet of this size.

• The study has been published in the journal Science.

When compared to planets in our solar system - Neptune and Uranus -that have the same mass, the distant planet (HAT-P-26b) is likely to have formed either closer to its host star or later in the development of its planetary system or both.

Significance

• The study would help in understanding more about the birth and development of planetary systems.

• The data obtained will also come handy in estimating the HAT-P-26b’s metallicity, which is an indication of the composition of elements heavier than hydrogen and helium.

• The planet’s metallicity was found to be about 4.8 times that of the Sun.

• This could help in understanding the planet formation.