Astronomers have found water vapor in the atmosphere of a planet 124 light years away.

The planet, HAT P-11b, is four times the radius of Earth and 26 times the mass. It is located in the constellation Cygnus 729 trillion miles away, according to Space.com.

"Water is the most cosmically abundant molecule that we can directly observe in exoplanets, and we expect it to be prevalent in the upper atmospheres of planets at these temperatures," lead author Jonathan Fraine said in an email interview, according to Space.com.

Fraine, a graduate student at the University of Maryland, worked with a team lead by Drake Deming, also of the University of Maryland.

"Detecting it is both a confirmation of our theories and revealing for the bulk of the spectrum that we can observe," Fraine told Space.com.

The planets in our system are created by a process called core accretion, which is a process where smaller particles combine to create larger particles, eventually reaching planet-size proportions.

Large planets far from the sun were able to attract huge amounts of hydrogen gas to create water early on in this process.

In large planets the water only occurs at deep levels, making it hard to observe.

Researchers believe that it is important to study small planets because it is more likely there will be heavy molecules, like water vapor and hydrogen.

"Our ideas about the formation of planets have been developed to match our solar system, and we don't know whether other planetary systems behave the same way," said Deming, according to Space.com. "We want to test the fundamental question of whether small planets are rich in heavy elements, like the oxygen in water vapor."

Small planets are hard to study due to their size, and HAT P-11b is the smallest planet where scientists have been able to identify chemical components in the atmosphere, according to Space.com.

The discovery of water vapor on exoplanets is important since water is a precondition of life. It's not enough to suggest that there is life on HAT P-11b or will ever be however.

"In the long run, if we can detect water, methane, carbon monoxide, carbon dioxide, etc., in dozens to hundreds of exoplanet atmospheres of various bulk properties, then we will be able to paint a much clearer picture of how planets form, and, likewise, how Earth formed," Fraine said.

"This was just one of the beginning brush strokes to painting the full picture of how planets, as well as ourselves, were formed."

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