Hubble Finds 3 (Relatively) Dry Exoplanets, Raising Questions About Water Outside The Solar System

Surprise! Three planets believed to be good candidates for having water vapor in their atmosphere actually have much lower quantities than expected.

The planets (HD 189733b, HD 209458b, and WASP-12b) are “hot Jupiters” that are orbiting very close to their parent star, at a distance where it was expected the extreme temperatures would turn water into a vapor that could be seen from afar.

But observations of the planets with the Hubble Space Telescope, who have temperatures between 816 and 2,204 degrees Celsius (1,500 and 4,000 degrees Fahrenheit), show only a tenth to a thousandth of the water astronomers expected.

“Our water measurement in one of the planets, HD 209458b, is the highest-precision measurement of any chemical compound in a planet outside our solar system, and we can now say with much greater certainty than ever before that we’ve found water in an exoplanet,” stated Nikku Madhusudhan, an astrophysicist at the University of Cambridge, England who led the research. “However, the low water abundance we have found so far is quite astonishing.”

This finding, if confirmed by other observations, could force exoplanet formation theory to be revised and could even have implications for how much water is available in so-called “super-Earths”, rocky planets that are somewhat larger than our own, the astronomers said.

Kepler-62f, an exoplanet that is about 40% larger than Earth. It’s located about 1,200 light-years from our solar system in the constellation Lyra. Credit: NASA/Ames/JPL-Caltech

That theory states that planets form over time as small dust particles stick to each other and grow into larger bodies. As it becomes a planet and takes on an atmosphere from surrounding gas bits, it’s believed that those elements should be “enhanced” in proportion to its star, especially in the case of oxygen. That oxygen in turn should be filled with water.

“We should be prepared for much lower water abundances than predicted when looking at super-Earths (rocky planets that are several times the mass of Earth),” Madhusudhan stated.

The research will be published today (July 24) in the Astrophysical Journal.

Source: NASA

Elizabeth Howell

Elizabeth Howell is the senior writer at Universe Today. She also works for Space.com, Space Exploration Network, the NASA Lunar Science Institute, NASA Astrobiology Magazine and LiveScience, among others. Career highlights include watching three shuttle launches, and going on a two-week simulated Mars expedition in rural Utah. You can follow her on Twitter @howellspace or contact her at her website.

Recent Posts

Hubble Spots Two Open Clusters. One is Also an Emission Nebula

Open star clusters are groups of stars in loosely-bound gravitational associations. The stars are further…

44 mins ago

Ground Telescopes can Adapt to Satellite Megaconstellations if They get Accurate Telemetry Data

The growing population of communication satellites such as Starlink and OneWeb is posing challenges for…

3 hours ago

Want to Colonize Space? Unleash the Power of Microbes

If space colonization is in our future, we'll have to use the resources available there.…

3 hours ago

By Looking Back Through Hubble Data, Astronomers Have Identified six Massive Stars Before They Exploded as Core-Collapse Supernovae

Using images from the Hubble Snapshot Program and archival data, a team of astronomers has…

6 hours ago

Maybe we don’t see Aliens Because They’re Waiting to Hear a Signal From us First

We've had a long-running series here at UT on potential solutions Fermi Paradox - why…

9 hours ago

NASA Wants to Build Landing Pads on the Moon

NASA has started engaging with commercial partners are some out-there projects. One of the most…

10 hours ago