Image of the Day: Sunset on the Alien Planet Osiris HD209458b

             

The amazing image above of a sunset on exo-planet HD209458b 150 light years away, was reconstructed by Frederic Pont of the University of Exeter using data from a camera onboard the Hubble Space Telescope. Pont used his knowledge of how the color of light changes based on chemicals it encounters, and computer modeling, to create an actual image of what a sunset on the actual planet would look like. He’s posted it on his blog.

The large exo planet in question, exoplanet HD209458b, nicknamed Osiris, circles its star rather closely. At certain points, when the planet passes between us and its star, the light from that star passes through Osiris’s atmosphere before reaching us, which allowed Pont to determine the chemical composition of the atmosphere and deduce what colors would appear to the naked human eye.

The light from Osiris’s star is white, like our own sun, but when it passes through the sodium in Osirisi’s atmosphere, red light in it is absorbed, leaving the starlight to appear blue. But as the sun sets, the blue light is scattered in the same way as it is here on Earth (Rayleigh scattering) causing a gradual change to green, and then to a dim dark green. And finally, due to diffraction, the bottom of the image becomes slightly flattened.

The Daily Galaxy via Hubble/ESA  and Frederic Pont

Comments

[Bob Greenwade]

Very nice image -- worthy of the "Image of the Day" title -- and well-written accompanying article (despite a minor punctuation glitch, and who isn't guilty of that every so often?).

And it's about time we started to get some better names for exoplanets than just alphanumerics. "Osiris" is so much easier for laymen (such as myself) to deal with than "HD209458b."

[MAC]

There can be no "sunsets" on alien planets. I'm sure you meant starsets.

[gd gal]

"Sun" can be defined as the host star of a particular planet, so it's "sunset"

[Rev. Carl Bowers]

With an estimated 160 billion exoplanets in our galaxy alone (see preceding article), we'd soon run out of ordinary-language names; I'm afraid alphanumerics will have to do for most of them.

[Fred]

The flattening of the bottom of the setting sun is due to refraction, not diffraction.

[smartypants]

Fred
Maybe on that planet they say diffraction for refraction?

[Brandon lea]

Either way we will never develop technology to travel to other stars if we dont stop spending money on welfare and wars. We need to have a similar operation like the manhatten project during ww2. House all our top scientists to develop new engines for space craft.

[Nightdog]

about "sun".

Yeah sun is a general term as MAC says. Our sun is named "Sol". The name might change from culture to culture, but I believe it is acknowledged in the scientific community that the name is "Sol" (from Latin). Wiki supports me btw...

[exoplanet HD209458b, Osiris]

*pats Nightdog on the head*