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.
Methuselah
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.
HIP13044b
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 Copyrights: Bad Astronomy Blog
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Which is your favorite (exo)planet? Please share in the comments.
Which is your favorite (exo)planet? Please share in the comments.
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