spaceSpace and Physics

Astronomy Student Discovers "Warm Neptune" Exoplanet Within Habitable Zone


Robin Andrews

Science & Policy Writer

15 Astronomy Student Discovers "Warm Neptune" Exoplanet Within Habitable Zone
If this planet has any moons, they may contain liquid water and, possibly, life. sdecoret/Shutterstock

Exoplanets, those that orbit alien stars far beyond the reaches of our Solar System, are fairly difficult to find. Thankfully, the Kepler space observatory has had its beady eye on the dark, shadowy depths of the cosmos for some time now, and as a result, researchers now know there are at least 5,000 of the sneaky planets out there.

As a new study submitted to The Astronomical Journal reveals, NASA’s researchers may have missed a few along the way: After looking through a sizable chunk of Kepler data herself, astronomy student from the University of British Columbia (UBC), Vancouver, has likely discovered four exoplanets of her own, including a very rare “warm Neptune.”


Catalogued as Kepler Object of Interest (KOI) 408.05, this planetary candidate – one waiting for official confirmation of its existence – is located 3,200 light-years away from Earth, and it is found within the so-called “habitable zone” of its star. This means that liquid water may be present on the surface, and as scientists are becoming acutely aware, wherever there is water, there is life.

“Like our own Neptune, it’s unlikely to have a rocky surface or oceans,” Michelle Kunimoto, a freshly-minted UBC physics and astronomy graduate and lead author of the study, said in a statement. “The exciting part is that like the large planets in our solar system, it could have large moons and these moons could have liquid water oceans.”




The orbits of the four new planets compared to Earth’s own orbit around the Sun. ubcpublicaffairs via YouTube

After sifting through reams of Kepler data, Kunimoto realized that there were small “blips” or data points that NASA’s own researchers may have overlooked. These data points took the form of transits, short dips in the host stars’ brightness that indicate a planet may have crossed in front of them. In some cases, this can be caused by a swarm of fragmenting comets, but in this case, Kunimoto is certain that the four objects are brand new exoplanets.

The first three vary in size: Two are the size of Earth, and one is somewhat larger than Neptune; all three orbit very close to their host star. Based on their orbits and sizes, their equilibrium temperatures – those generated solely by incoming solar radiation being remitted from the surface – range from 463°C to 1,381°C (865°F to 2,518°F), meaning that they are unlikely to contain much liquid water, if any.

The so-called warm Neptune, however, has an equilibrium surface temperature of around -21°C (-5.8°F). Although this is below the freezing point of water, this is very similar to Earth’s equilibrium temperature. Earth is far warmer than this thanks to its thick atmosphere creating a warming greenhouse effect, and the same could be operating on KOI 408.05.


An artist’s impression of the four new exoplanets compared to Earth, Mercury and Neptune. Michelle Kunimoto & Jaymie Matthews

The team also suggest that any moons this planet may have will also reside within the same warm solar radiation envelope. They compare these hypothetical moons to Pandora from the movie “Avatar,” although the forest moon of Endor from the “Star Wars” franchise could be just as applicable.

At least four previously confirmed exoplanets already orbit this particular star, meaning that KOI 408.05 is likely to be the system’s fifth planetary member. Although it still needs to be verified, it appears that yet another potential habitable exoplanet has been found – and that’s always something to celebrate.


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