Space Fan News #56: New Type of Exoplanet; Andromeda Outbursts; Neutrino Errors


Uploaded by tdarnell on 24.02.2012

Transcript:
Hello Space Fans and welcome to another edition of Space Fan News.
Up first, it looks like Hubble has discovered a new kind of exoplanet: a world covered in
a thick, dense atmosphere with more water than rock.
Known as GJ1214b - it is a super-earth - and it was first discovered in 2009 from ground-based
telescopes belonging to Mearth, a project that uses robotic telescopes to measure planet
transits of M class dwarf stars.
This super-Earth, some 40 light years away, is about 2.7 times Earth's diameter and weighs
almost seven times as much, so it's smaller than Uranus and larger than Earth.
It orbits a red-dwarf star once every 38 hours (that's its year) at a distance of 1.3 million
miles, giving it an estimated temperature of 232 degrees Celsius, or 450 degrees Fahrenheit.
What, you say? This seems strange. Did you say 450 degrees? "How can liquid water be
on a planet that is that hot? Wouldn't it all evaporate away?"
Well, turns out this planet is a little stranger than that. When they first found this thing,
all they knew was that the spectrum of the planet showed that a large percentage of its
mass was made of water, that's it.
So later, using Hubble's Wide Field Camera 3 (an infrared camera I'd like to add...),
they were able to look very closely at the limb of the planet and measure the light from
the red dwarf as it went by to measure the atmosphere.
The star's light was filtered through the gasses which allows us to measure how much
of each different type of gas is in there as well as get an idea of its density because
we also know the planet's mass and size.
So what they found was pretty cool:
The atmosphere is very dense, about twice as dense as the density of water. Water has
a density of 1gm/cm^3, this planet's atmosphere is 2g/cm^3.
For reference, Earth's atmosphere is 5.5g/cm^3.
This suggests that GJ1214b has more water than Earth, and much less rock.
So what they're saying is that there isn't liquid water there but something far more
strange, the high pressures combined with the high temperatures found there wouldn't
cause the water to evaporate, but instead make some really weird stuff, like 'hot ice'
or 'superfluid water' these are states that aren't possible here naturally, but would
be common on GJ1214b.
When it comes to how this planet came about in the first place, what they think happened
is that this planet formed farther out from its star than where we see it now, where water
ice was plentiful, and then it migrated closer in early in the system's history.
It's also interesting to note that in the process of doing that, it would have passed
through the star's habitable zone.
How long it stayed there no one knows.
So now we know about all kinds of exoplanets: rocky worlds, super Earths, lava worlds, Gas
Giants and Hot Jupiters, and the latest type just discovered by Hubble, a hot, steamy water
world, with some pretty strange water.
Next, the Andromeda Galaxy has an outburst.
For about two months at the end of 2009, early 2010, a very bright burst of X-rays was observed.
The type of burst they saw is pretty rare, only one or two per galaxy, and they are called
Ultraluminous X-ray sources or ULX'es.
They are found in both the nearby and the distant Universe, where they are seen in the
outer regions of galaxies.
Because they don't happen very often, astronomers aren't really sure what they are. They are
either a stellar mass black holes accreting surrounding material at extreme rates or there
is a new sub-species of intermediate mass black holes accreting at lower rates (remember
I talked about those last time? They have found these intermediate black holes.).
Soooo Just to remind those who don't watch every Space Fan News.... Incredibly!
Intermediate black holes are those with masses between 100 and 100,000 times the mass of
our Sun. Any smaller than that they are stellar sized, any larger and they are supermassive
black holes.
Well with this ULX, they got lucky. They were able to catch it right after it started and
get a complete light curve, and it happened relatively close by in our neighboring galaxy
only 2.5 million light years away. So this is also the closest ULX ever observed.
What they were able to find out is that the light curve from this eruption showed a very
similar behavior to other X-ray sources from our own galaxy.
The emission light curve decayed exponentially with a characteristic timescale of about one
month, which is a common property of stellar mass X-ray binaries. This means that the ULX
in Andromeda likely contains a normal, everyday stellar black hole swallowing material at
very high rates.
At it's peak, this ULX produced more X-ray output than the entire galaxy.
Uhn-kay, finally... Remember those faster than light neutrinos? Well, now they're thinking...
notsomuch.
Looks like they had a loose fiber optic cable with a finicky connection that may have caused
errors in the GPS signal.
Remember, this experiment is done underground and GPS satellites can't go through rock,
so they have to pipe the signal in. The connector on the fiber optic line carrying that signal
was apparently caddywhompus and was one of two sources of error they found.
They also had another problem with an oscillator, but they say if you tried to correct for that
error, you'd get an even faster flight time for the neutrinos. So now it's a question
of which source was bigger and dominated.
They don't know which source of error had the larger effect, the GPS connector or the
oscillator, so they're still sorting that out.
But, later this Spring, several independent teams plan on doing their own, separate experiment
to see if they can repeat the faster than light result.
So, I'll let you know...
Well, that's it for this week Space Fans, thanks for watching and, as always, Keep Looking
Up.