The atmospheres of exoplanets share some common properties, but also hold a few mysteries.
Water in the Sky
The transit method of exoplanet observation looks at the light from a star to observe dips in brightness. When a planet passes in front of a star (transits), it blocks some of the starlight, making the star appear slightly dimmer. Normally when we are looking for exoplanets we simply look for an overall dip in brightness, from which we can determine things such as the size of the planet relative to the star.
But once an exoplanet is known, you can begin to make more subtle observations, such as observing the dip at different wavelengths. This was done by a team recently to study the atmosphere of an exoplanet known as Gliese 1214 b. Their results were recently published in the Astrophysical Journal.
Diamond Sky
A neutron star is the remnant of a large supernova. When a large star explodes, a remnant of its core is compressed so tightly that the electrons are squeezed into protons, resulting in a mass of neutrons. A neutron star typically has a mass of about 2 solar masses, but it is only about 12 kilometers in diameter. Imagine taking two suns and squeeze it into the size of a small city, and you get the idea of how incredibly dense these objects are.
Rainbow Star
When we view stars from the surface of our planet, they appear to twinkle. This is due to turbulence in the air, which creates air fluctuations that cause the starlight to deflect slightly. Since stars appear point-like due to their distance, the small deflections are enough to cause the star to twinkle.
Usually we just notice the variation in brightness, but air also acts like a prism, bending different colors of light by different amounts. So not only do stars appear to vary in brightness, they can also appear to vary in color.
Sharing is Caring
With the New Horizons spacecraft on its way to Pluto, and scheduled to flyby the dwarf planet in 2015, there is a growing interest in this distant world. Much of this focuses on aspects of the planet that might be important for the flyby. A while back I talked about how computer simulations of Pluto and its largest moon Charon showed that they likely formed through a large collision, and as a result New Horizons should find additional plutonian moons.
All These Worlds
This post is about the atmospheric makeup of four planets orbiting a star 130 light years away. Think on that for a bit. We’re now able to study the atmospheres of extra-solar planets. What’s even more amazing is the work was done from a ground-based telescope.