MessageToEagle.com

Cosmic Irony - Planets Orbiting Cooler Stars More Likely To Remain Ice-Free
Than Planets Around Hotter Stars

20 July, 2013

Share this story:
Follow us:

MessageToEagle.com - Planets orbiting cool stars actually may be much warmer and less icy than their counterparts orbiting much hotter stars, even though they receive the same amount of light, shows a new study led by Aomawa Shields, a doctoral student in the University of Washington astronomy department.

This is due to the interaction of a star's light with ice and snow on the planet's surface.

Stars emit different types of light. Hotter stars emit high-energy visible and ultraviolet light, and cooler stars give off infrared and near-infrared light, which has a much lower energy.


Illustration of a planet with two moons orbiting a red dwarf in the habitable zone. Credit: David A Aguilar(CfA)


It seems logical that the warmth of terrestrial or rocky planets should depend on the amount of light they get from their stars, all other things being equal.

That's because the ice absorbs much of the longer wavelength, near-infrared light predominantly emitted by these cooler stars.

This is counter to what we experience on Earth, where ice and snow strongly reflect the visible light emitted by the Sun. Around a cooler (M-dwarf) star, the more light the ice absorbs, the warmer the planet gets.

The planet's atmospheric greenhouse gases also absorb this near-infrared light, compounding the warming effect.

The researchers found that planets orbiting cooler stars, given similar amounts of light as those orbiting hotter stars, are therefore less likely to experience so-called "snowball states," icing over from pole to equator.

However, around a hotter star such as an F-dwarf, the star's visible and ultraviolet light is reflected by planetary ice and snow in a process called ice-albedo feedback. The more light the ice reflects, the cooler the planet gets.

"The last snowball episode on Earth has been linked to the explosion of multicellular life on our planet," Shields said.

"If someone observed our Earth then, they might not have thought there was life here - but there certainly was. "So though we'd look for the non-snowball planets first, we shouldn't entirely write off planets that may be ice-covered, or headed for total ice cover."

"There could be life there too, though it may be much harder to detect."

The research paper is published in the August issue of the journal Astrobiology, and published online ahead of print July 15.


MessageToEagle.com

See also:
Mysterious Flares Emitting From Sagittarius A

Follow MessageToEagle.com for the latest news on Facebook and Twitter !

Don't Miss Our Stories! Get Our Daily Email Newsletter

Enter your email address:


Once you have confirmed your email address, you will be subscribed to the newsletter.

Recommend this article:

Thermonuclear Burning In A Neutron Star Detected For The First Time!

Black Gaps In The Sky Puzzle Astronomers

Mysteries Of A Dark Universe

Peculiar Nebulous Objects

Countless Trillions Of Glowing Orbs That Illuminate The Universe

Possible Water In The Atmosphere Of A Super-Earth

Astronomical Mystery - Tremendous Explosion And Appearance Of Odd Rings

Subscribe To Our Space, Astronomy, Astrophysics, Earth and Xenology News!

Grab the latest RSS feeds right to your reader, desktop or mobile phone.


comments powered by Disqus

Subscribe to RSS headline updates from:
Powered by FeedBurner

Go to - MAIN PAGE

Copyright @ MessageToEagle.com All rights reserved.
Go to - MAIN PAGE

 Subscribe in a reader

Join Us On Facebook!


Other Popular Articles

Doesn't Secret Dark Matter Exist?
The more scientists study dark matter they know lesser and are not particularly optimistic about their results.
After completing this study, we know less about dark matter than we did before," said Matt Walker, of the Harvard-Smithsonian Center for Astrophysics.
A mysterious and still unknown substance is totally invisible in the Universe and reveals its presence only through its gravitational pull...

First Discovered Carbon-Rich Planet: Could It Harbor Life?
WASP-12b is the first carbon-rich world ever observed. It is an extremely hot and large gas giant orbiting another star and it has unusual amount of carbon. Carbon is a common component of planetary systems and a key ingredient of life on Earth. Does it mean some kind of life might exist on WASP-12b?

Listen To The Song Of The Sun
The sun gives off more than just heat and light. One astronomer thinks it makes music, too. From here on Earth, that great ball of fire in the sky appears to be perfectly round. But closer study reveals storms and giant gaseous eruptions covering the surface of the sun. Now one scientist has found a way to translate those eruptions into strangely beautiful music.

Huge Superflare In The Crab Nebula
The famous Crab Nebula supernova remnant has erupted in an enormous flare five times more powerful than any flare previously seen from the object. On April 12, NASA's Fermi Gamma-ray Space Telescope first detected the outburst, which lasted six days...

Abnormal Star Discovered In The 'Forbidden Zone'
A team of astrophysicists from Germany, France and Italy have discovered in the constellation Leo is an old star. The star's existence raised at once many questions for scientists. The object is definitely not as its "contemporaries" that appeared immediately after the Big Bang event.


Thermonuclear Burning In A Neutron Star Detected For The First Time!
It's a very important discovery! For the first time, an international team of scientists have detected all phases of thermonuclear burning in a neutron star, located close to the center of the galaxy in the globular cluster Terzan 5.

Possible Water In The Atmosphere Of A Super-Earth
Four CfA astronomers, Zachory Berta, David Charbonneau, Jean-Michel Desert, and Jonathan Irwin, together with six colleagues, used the Hubble Space Telescope to probe the atmosphere around the transiting super-Earth known as GJ1214b. This exoplanet has a mass of 6.5 Earth-masses and a radius of 2.7 Earth-radii, and it orbits a small M-dwarf star (its diameter is only 21% of the Sun's).

Astronomical Mystery - Tremendous Explosion And Appearance Of Odd Rings
Twenty five years ago, on 1987 February 23, the brightest supernova of modern times was observed in the Large Magellanic Cloud.
The collision occurred at speeds near 60 million kilometers per hour and shock-heats the ring material causing it to glow.
Over time, astronomers have watched and waited for the expanding debris from this tremendous stellar explosion to crash into previously expelled material...

Doesn't Secret Dark Matter Exist?

Dwarf Irregular Galaxy That Forces Scientists To Re-Evaluate Old Theory

The Eyes Of A Future Alien Astronomer - What Will They See?
Have you ever wondered what the Universe will look like for a future alien astronomer?
It will in fact be entirely different from what it is today. One trillion years from now, an alien astronomer in our galaxy will have great difficulties figuring out how the universe began.
The Milky Way will have merged with the Andromeda galaxy to form the Milkomeda galaxy. Many of its stars, including our Sun, will have burned out.

Violent Dragon Clash Billions Of Years Ago

Researchers Developed A Very Accurate Map Of Milky Way's Magnetic Field
The Milky Way is hard to map because we are sitting on the edge of the galaxy looking through it. However, we know that spiral galaxies like the Milky Way have magnetic fields that follow a particular pattern so we were able use polarised light to map the magnetic fields...

W3Counter