Exoplanets

We’ve Found A Primitive Atmosphere Around A ‘Warm Neptune’

We've Found A 'Primitive Atmosphere' Around A Warm Neptune

It’s such an amazing time to be alive. Every week we’re discovering new and exciting facts about our universe that we never thought possible. Most recently, NASA has just found an early atmosphere forming around a ‘warm neptune’.

A distant planet named HAT-P-26b has been found with what is being labelled a primitive atmosphere composed of hydrogen and helium. Research indicates that the atmosphere is ‘relatively clear of clouds’ and has a strong water signature.

“Astronomers have just begun to investigate the atmospheres of these distant Neptune-mass planets, and almost right away, we found an example that goes against the trend in our solar system. This kind of unexpected result is why I really love exploring the atmospheres of alien planets.”

– Hannah Wakeford, a postdoctoral researcher at NASA’s Goddard Space Flight Center




 

What Is A Warm Neptune?

By definition, a warm or hot Neptune is a “type of giant planet with a mass similar to that of Uranus or Neptune in an orbit close to its star, normally less than 1 AU. The first hot Neptune to be discovered with certainty was Gliese 436 b in 2007, an exoplanet about 33 light years away. Recent observations have revealed a larger potential population of hot Neptunes in the Milky Way than previously thought.”

The atmosphere of the distant “warm Neptune” HAT-P-26b, illustrated here, is unexpectedly primitive, composed primarily of hydrogen and helium. By combining observations from NASA’s Hubble and Spitzer space telescopes, researchers determined that, unlike Neptune and Uranus, the exoplanet has relatively low metallicity, an indication of the how rich the planet is in all elements heavier than hydrogen and helium.
Credits: NASA/GSFC



 

A Surprising Diversity Of Warm Neptunes

We’ve found other warm Neptune’s in the past, and now NASA has a system to compare and classify them amongst each other. Scientists compare planets by their ‘metallicities’ which is an indication of how rich the planet is in all elements heavier than hydrogen and helium. This gives an insight into how the planet formed, and what the atmospheres may be comprised of.

“This analysis shows that there is a lot more diversity in the atmospheres of these exoplanets than we were expecting, which is providing insight into how planets can form and evolve differently than in our solar system. I would say that has been a theme in the studies of exoplanets: Researchers keep finding surprising diversity.”

– David K. Sing of the University of Exeter




 

HAT-P-11b, and WASP-43b are two similar warm neptune’s that fit the same characteristics. WASP-43b, is the largest known warm Neptune at an estimated size of twice that of Jupiter.

via: NASA

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Jamie is an amateur astronomer and every day space geek.