Monday, February 27, 2012

Really Cool Exoplanets

Exoplanets are planets that orbit other stars. Until 20 years ago, the only planets known to mankind were the nine around own Sun. Fast forward to 2012 and Pluto is no longer a proper planet, so we are left with just eight companions in the solar system but (mostly through the extremely successful Kepler mission) we now know of hundreds of planets in other systems. Some of them are really cool (metaphorically, most of them are extremely hot!). Here are my personal favorites.


Scientifically designated as PSR B1620-26b, Methuselah is the oldest known exoplanet. It is located in the globular cluster Messier 4 and along with the stars in this cluster (globular cluster members form almost concurrently), the planet is estimated to have formed 12.7 billion years ago. This is merely 1 billion years after the Big Bang. Imagine how different the universe was back then - there were small irregular galaxies and very few heavy elements (there was not enough time for a significant number of supernovae to ignite). And as if being the oldest exoplanet is not awesome enough, Methuselah also is a member of a very curious binary star system. The pair that harbors Methuselah includes a white dwarf and a pulsar. Yes, both of those are dead stars but this also means that at some point in the lifetime of the planet, one of its hosts went supernova! Born just after the Big Bang and survived a supernova - this is what I call a fighter planet. Even if Methuselah only formed around the white dwarf and was later trapped by the pulsar, having those two very dense "parents" is still quite cool.
Messier 4 Globular Cluster
Image Copyrights: Messier

GJ 667Cc and GJ 667Cb

GJ 667Cc and GJ 667Cb are two exoplanets in a triple star system. Gliese 667 is located mere 22.1 light years away from the Earth in the constellation of Scorpius. According to the laws of celestial mechanics, triple star systems are quite complex and unstable, just like in human relationships most of the times one of the threesome gets kicked away. This is actually considered to be the source of energy for globular cluster core-collapse. Gliese 667, however, is not part of a globular cluster and the system is stable. As in most other instances of stable three body systems - two of the  component stars orbit each other quite close (GJ 667A and GJ 667B) , while the third one GJ 667C is relatively distant. And as if three stars are not gravitational headache by themselves, Gliese 667 also has planets! Research until now has confirmed at least 2 planets orbiting GJ 667C. The planets are both a lot closer to GJ 667C than our home planet to our favorite star (0.049 and 0.23 respectively) and therefore their parent star looks quite enormous on their horizons and is joined by B and A for truly spectacular sunsets and sunrises.

 Image CopyrightsMix Techno News


HIP13044b is literally an alien world - it is an exoplanet from another galaxy. This planet and its star are part of the Helmi Stream of stars in the Milky Way galaxy. This stream consists of the remnants of a dwarf galaxy consumed by the Milky Way 6 billion years ago - i.e. before the Sun or the Solar System even formed. HIP13044 is also a very old star which is already past its red giant stage and is currently fusing helium into carbon. HIP13044b, however, orbits its primary quite close so when the star was a red giant it is possible that the planet spent a lot of time physically inside its star! Deep fried but still standing. So to sum up - this little warrior survived the collision of its galaxy with the Milky Way (which is not such a danger - the chances of two stars colliding are minuscule - just like the atoms, galaxies are mostly empty/dark matter filled space) and the red giant phase of its star but it still kicking. I wonder if (alien) life is as resilient as these alien worlds?

Image CopyrightsBad Astronomy Blog

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Which is your favorite (exo)planet? Please share in the comments.

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