Hello Space Fans and welcome to another edition of Space Fan News.
Those who have been with me from the beginning know that Space Fan News was born six years
ago this week when I wanted to report to you some of the biggest and most exciting astronomical
discoveries that were announced during the winter conference of the American Astronomical Society.
I started six years ago with SFN #1 and now six years later, we are still at it.
So, welcome to AAS Week on Space Fan News!
There was lots of great science that came out of this week's 229th Meeting of the
American Astronomical Society in Grapevine Texas, so much that I can't possible report
on all of it, instead, I'm just going to give you some highlights of some of the biggest
stories that I thought were interesting.
First up, there was a lot of excitement over the pinpointing of the source galaxy of something
called a Fast Radio Burst or FRB.
FRB's are sudden, rapid explosions of energy that have had astronomers scratching their
heads since they were first discovered in 2007.
They typically last only a few milliseconds and no one really knows what they are nor
what is powering them.
They also had no idea what their host galaxies looked like, until now.
The thing about FRB's is that they happen once, very fast, and then that's it, they're
gone.
This means that once they are detected, there's no way to follow up with any other kind of
telescope to get more information on what these things are.
There are only 18 known FRB's and all were discovered using single-dish radio telescopes
that can't narrow down the object's location with enough precision to allow other observations
to identify the host galaxy using visible or infrared telescopes.
But that all changed last year with the discovery of an FRB called FRB 121102, a Fast Radio
Burst that had the courtesy to keep on bursting, numerous times.
That little bit of recurring serendipity allowed astronomers using the Very Large Array in
New Mexico to get a look at it the next time it went off.
Because it has multiple antennas, it can triangulate the position of the FRB more precisely.
In 83 hours of observing time over six months in 2016, the VLA detected nine bursts from
FRB 121102 and allowed them to narrow down the position of the FRB very accurately.
That allowed astronomers using the Gemini North Telescope on Hawai'i to make a visible
light image of the galaxy to see where this thing was coming from.
So the punchline is that the host galaxy for this FRB appears to be a small and humble
dwarf galaxy, which has only about one percent of the mass of our Milky Way galaxy and is
about three billion light years from Earth.
Astronomers were surprised that this Fast Radio Burst came from a dwarf galaxy, they
were expecting it to come from large galaxies because they contain more neutron stars, which
right now are the top candidates to explain what the heck these things are, but since
it came from a small galaxy, now they're really confused.
This dwarf galaxy has fewer stars but it is forming them at a very high rate, which may
suggest that FRB's are linked to younger neutron stars.
Two other classes of extreme events – long duration gamma-ray bursts and superluminous
supernovae – also occur in dwarf galaxies so this discovery may hint at links between
FRBs and those two kinds of events.
FRB's are an exciting new area in astrophysics so astronomers are keen to get more observations
and they want to use surveys that can see the entire area of the sky at once such as
the Dominion Radio Astrophysical Observatory's CHIME Telescope in Canada which will survey
half the sky each day in search of radio transients.
I'll keep you posted.
Next, NASA has selected the next two missions to explore the early solar system.
On Wednesday, NASA said it chose the LUCY and Psyche Mission from five finalists.
LUCY is scheduled to launch in October 2021 and will visit a target-rich environment of
Jupiter's mysterious Trojan asteroids while Psyche will study a unique metal asteroid
that's never been visited before and will launch in October 2023.
Ever notice how October is a great month for launching robotic spacecraft?
Both of these missions are part of NASA's Discovery Program is a class of missions that
are highly targeted, relatively cheap to build and have well-defined science goals.
The New Horizon's mission to Pluto was a discovery-class NASA mission, so they are
quite profitable scientifically and is one way NASA is able to do so much great work
with so little money.
I'll keep you updated on these missions as they get built and milestones are reached,
but I wanted to let you know they were selected this week as NASA's next robotic craft to
study the solar system.
Also announced this week at the AAS meeting was the discovery of an entirely new kind
of galaxy.
Astronomers at the University of Minnesota Duluth and the North Carolina Museum of Natural
Sciences have identified a new class of ring galaxy.
Named PGC 1000714, it features an elliptical core with not one, but two outer rings.
It's the only known galaxy of its kind in the known universe.
Most galaxies in the universe are either disk-shaped spirals or egg-shaped ellipticals and there's
a smattering of other kinds of galaxies too, like lenticular, irregular, dwarf and extremely
low density galaxies known as ultra diffuse objects.
There's another kind too, called a ring galaxy which were discovered in the 1950's
and are very rare, less than 0.1 percent of the galaxies in the universe are ring galaxies.
The most famous is this one, call Hoag's Object after the astronomer who first observed
these, Arthur Hoag.
But PGC 1000714 is different enough from ring galaxies that it deserves its own sub-classification:
it has an elliptical core, like a ring galaxy, but it is surrounded by two discernable and
independent rings.
So if Hoag gets a galaxy type named after it, so does this one: they're calling Burcin's
Galaxy after the lead author of the paper who discovered it, Burcin Mutlu-Pakdil.
It is about 359 million light-years away and
its unusual structure is providing astronomers with unique insights into how galaxies form
and evolve.
And finally, I didn't want to close out this AAS Week episode without an update on
JWST.
We had a hangout scheduled in mid-December with the JWST mission to give us an update
on how things were going when it had to be cancelled because of an unexpected result
from a vibration test that was performed on December third.
On that day, while testing at the Goddard Space Flight Center, unexpected reading appeared
on accelerometers in response to a frequency equivalent to a very low A flat on a piano,
which lead to an immediate halt to the testing.
These vibration tests are done using specific frequencies that have resonances that can
cause damage to equipment during launch, and this damage is very difficult to repair once
in space so NASA wants to identify any weaknesses now, well before launch.
After this happened, the mission team scientists have conducted a variety of visual and ultrasound
tests to see if they could find out what the cause of the anomaly was and they are closing
in on what caused it and NASA has announced this week that they expect to resume the vibration
and shock testing later this month.
When testing picks back up, they will focus on measuring the resonances of both the telescope
and its individual components to assure that it can successfully make it into orbit.
This year promises to be a big one for JWST and thankfully we have rescheduled our hangout
for January 19th and we'll give you a more complete update then, so mark your calendars
to find out about the latest in the mission that will launch the largest space telescope
ever built.
Well that's it for this week Space Fans, thanks to all SFN Patreon Patrons who've
made 2016 a great year and I'm looking forward to making more great episodes in 2017.
Thanks to all of you for watching and as always, Keep Looking Up!
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