Space Fan News #43: Kepler-22b; Biggest Black Holes EVER!; Swift Sees a Strange GRB

Hello Space Fans, welcome to another addition of Space Fan News.

So the big news this week came out on Monday with the announcement of the confirmation of Kepler-22b, a roughly Earth-sized planet around the habitable zone of a star a lot like the Sun.

I posted a video about this on Tuesday called "The Promise of Kepler-22b" where I posted all we know about this planet.

All I want to say about it today is emphasize that we really don't know much about Kepler-22b.  All we've learned is what can be gleaned by watching a planet pass in front of a star because that's the kind of observation Kepler does.  So there's not a lot of details we can get from an observation like that, but we can get some things.

Things like:

We know its size: it has a radius roughly 2.4 times that of Earth

We know it's orbit around Kepler-22: it takes 290 days to orbit once around it.

We know the star is like our Sun and I've heard statements that it is 10 billion years old.

We know how far away it is: 600 light years.

That's it.

We don't know what it's made of; we don't know if it is rocky or not; we don't know if it even has an atmosphere.

Those things are usually detected spectroscopically and the Kepler-22 system is so far away and the planet so small that even if we put our best spectrographs on it, we wouldn't be able to measure it.  Just too far away.

Now... the James Webb Space Telescope on the other hand will have instruments onboard uniquely able to look at exoplanets and determine these things.  It has a large enough primary to possibly even resolve many of these systems.

Which is reason number 812 why we need the JWST.

So if you don't know about it or haven't seen it yet, check out my video posted on Tuesday, you can find it easily on my channel page.

Next, astronomers have found the largest black holes ever.

EVER!

Earlier this week it was announced that astronomers using the Gemini North Telescope in Hawai'i - along with researchers from the universities of Texas, Michigan, the Dunlap Institute for Astronomy and Astrophysics at the University of Toronto, Canada, as well as NOAO in Arizona - have found two supermassive black holes, each approaching 10 billion solar masses.

Now here's some persepective:  the supermassive black hole at the center of the Milky Way is only four million solar masses.  The one in the center of the Andromeda galaxy is 140 million solar masses.

These black holes are a in a different league entirely.

The event horizons of each of these black holes is five to ten times bigger than the orbit of Pluto.

These are 10 billion solar mass black holes.  We're talking about black holes two thousand times bigger than the one at the center of our galaxy.

Whoa.

Remember, there are two basic classes of black holes: there are stellar sized black holes that are floating around inside our galaxy.  Then there are supermassive black holes devouring stars in the centers of galaxies and powering quasars.  We're talking about that kind here.

So now, with this discovery,  astronomers are starting to wonder just how big these things can get.

Very large black holes are thought to have been around when the universe was very young, from about one to three billion years after the Big Bang.  The evidence for this comes from quasars.  These are large, energetic sources believed to be the results of black holes devouring it's galaxy.  Quasars are among the most distant objects ever observed.  Since the distance from us is closely linked to how far back in time we're looking: the very, very distant objects we see in telescopes are from a time when the universe was young, so the existence of these quasars tells us there were powerful black holes around back then powering these quasars.

But that was 10 billion years ago, quasars are seen very far away, the quasars in nearby galaxies have gone dark, but the black holes are still there.  

So where are they now?  

Astronomers believe they are lurking at the centers of ancient elliptical galaxies.  Elliptical galaxies are smooth, featureless galaxies containing primarily older, low mass stars.  Very little star formation is happening here, these galaxies are dying.

The black holes at the centers of these galaxies are no longer fed by accreting gas and have become dormant and hidden. We see them only because of their gravitational pull on nearby orbiting stars.

The astronomers found these black holes in NGC 3842 and NGC 4889: each a giant elliptical galaxy and the brightest member of a galaxy cluster; NGC 3842 lies about 320 million light-years away in the Leo galaxy cluster, and NGC 4889 is the brightest member of the famous Coma galaxy cluster some 336 million light-years away. Both of these galaxies are bright enough to see in amateur telescopes, so look em up space fans.

Since astronomers have no idea what the upper limit on the size of a black hole can be, expect to hear more about larger and larger black hole discoveries in the future.

Finally, the Swift Space Telescope observed a very strange gamma ray burst.  Gamma-ray bursts, or GRBs. are the universe's most luminous explosions, emitting more energy in a few seconds than our sun will during its entire energy-producing lifetime. 

This burst, known as GRB 101225A, was discovered in the constellation Andromeda by Swift's Burst Alert Telescope at 1:38 p.m. EST on Dec. 25, 2010.

So you know what's coming next: yep.  It's being called the Christmas burst.

Oh well.

The gamma-ray emission lasted at least 28 minutes, which is unusually long. Follow-up observations of the burst's afterglow by the Hubble Space Telescope and ground-based observatories were unable to determine the object's distance.

This gamma ray burst is so unusual, astronomers think it could have happened in one of two ways.

One scenario says that a solitary neutron star minding its own business gets hit by a passing comet which it quickly devours, causing the gamma ray burst.

Another possibility is that the a neutron star is engulfed by, spirals into and merges with an evolved giant star in a distant galaxy.

Both scenarios involve a neutron star causing mayhem.

The team seems to be leaning toward the second scenario. 

They're proposing the burst occurred in an exotic binary system where a neutron star orbited a normal star that had just entered its red giant phase, enormously expanding its outer atmosphere. This expansion engulfed the neutron star, resulting in both the ejection of the giant's atmosphere and rapid tightening of the neutron star's orbit.

Once the two stars became wrapped in a common envelope of gas, the neutron star may have merged with the giant's core after just five orbits. The end result of the merger was the birth of a black hole and the production of oppositely directed jets of particles moving at nearly the speed of light, followed by a weak supernova.

The particle jets produced gamma rays. Jet interactions with gas ejected before the merger explain many of the burst's signature oddities. Based on this interpretation, the event took place about 5.5 billion light-years away, and the team has detected what may be a faint galaxy at the right location. 

Well, that's it for now Space Fans, as always thank you for watching, and Keep Looking Up.

Further Reading:

Kepler's first confirmed earth-sized planet in a habitable zone (Kepler 22B).

http://www.nasa.gov/mission_pages/kepler/news/kepscicon-briefing.html

http://www.jpl.nasa.gov/news/news.cfm?release=2011-373

http://www.mercurynews.com/science/ci_19475891

http://astrobites.com/2011/12/06/the-news-and-super-earth-kepler-22b/ <---Include stuff from here!

Habitable zone yes, but Kepler 22-b mass and high gravity rules out the possibility of terrestrial life

http://phl.upr.edu/projects/habitable-exoplanets-catalog

Comet Falling into Neutron Star

http://www.physorg.com/news/2011-11-christmas-day-cosmic-dying-comet.html

http://www.nasa.gov/mission_pages/swift/bursts/dual-burst.html

Kepler 21b Confirmed from Kitt Peak:

http://www.noao.edu/news/2011/pr1108.php

Strange new species of ultra-red galaxy discovered (might make a better IM):

http://www.cfa.harvard.edu/news/2011/pr201133.html

Two record-breaking black holes found:

http://www.gemini.edu/node/11703

http://www.nsf.gov/news/news_summ.jsp?cntn_id=122475&org=NSF&from=news

http://www.nsf.gov/news/news_summ.jsp?org=NSF&cntn_id=122472&preview=false

http://www.nytimes.com/2011/12/06/science/space/astronomers-find-biggest-black-holes-yet.html

http://www.universetoday.com/91625/astronomers-find-the-most-supermassive-black-holes-yet/?utm_source=Twitter&utm_medium=social&utm_campaign=WordSocial

http://www.cosmosmagazine.com/news/5066/astronomers-report-largest-black-hole-discovery

E-ELT Gets Funding Approval

http://www.eso.org/public/news/eso1150/

http://www.eso.org/public/teles-instr/e-elt.html

The Promise of Kepler 22-b

On December 5th, 2011, the Kepler Science team announced that they had confirmed a planet roughly the size of ours, in orbit around a star very similar to the Sun.

What's more, the distance of this planet from its star was perfect.  It wasn't too close, and it wasn't too far away.

If this planet were the Earth, life could live there.

It's called Kepler-22b.

The parent star, Kepler-22 is very similar to our Sun.  Classified as a sun-like G-type star, it is very dim as seen from Earth and measurements of dips in light as the planet passes in front are very difficult to make.

Nevertheless, the Kepler Space Telescope first noticed this star as having a planet that is possibly like Earth almost immediately.  A mere three days after being declared operationally ready, Kepler took notice that something was interesting in orbit around this small, dim, Sun-like star located 600 light years away.

Followup observations on the ground and from the Spitzer Space Telescope confirmed the planets existence.

Kepler-22b, the first Earth-sized planet found by Kepler in a habitable zone around another star, has been confirmed.  Of the 54 habitable zone planet candidates currently under scrutiny by the Kepler Space Telescope, this is the first to be confirmed.

Kepler-22b has a radius 2.4 times that of the Earth, putting this planet in a category commonly called a super-Earth.  It takes 290 days to travel once around around its sun, which is slightly smaller and cooler than ours.

The promise of Kepler-22b, however,  is tempered by what we do not know about it. There is much hidden from us.  The most glaring gap in our knowledge is that we don't know what it's made of.  It could be a rocky planet like Earth, or it could be gaseous and more like Neptune.

It may even be covered entirely of water, an ocean planet with an altogether new set of possibilities for life.

What we do know is that while Kepler-22b is Earth-like, it is hardly our twin.  At 2.4 times the radius of the Earth, if it is rocky and very dense, then life could be very hard here.  We also do not know if it even contains an atmosphere.

And if it does have an atmosphere, how much heat does the atmosphere trap?  If it traps too much, then Kepler-22b could be more like Venus, a planet known to be very inhospitable to life.

If it's a Neptune-like planet, made entirely of gas, then the chances for life, at least as we know it to be, are impossible.  Living here, any life would take on a completely unexpected form.

The chances for finding out the answers to many of these questions about Kepler-22b, while possible, are somewhat remote with our current levels of technology.  For example, using radial velocity measurements, a spectral technique that allows us to find out chemical compositions of stars, planets and their atmospheres, in addition to the planet itself by measuring the wobble of the star as the planet circles it, is not feasible for a star so far away with such a small planet in orbit around it.

Perhaps the biggest promise offered by the confirmation of Kepler-22b isn't the planet itself, but lies in the fact that it was found so soon after we started looking for planets like the Earth.  With Kepler, the number of Earth-sized candidate planets has increased 200 percent, and the number of super-Earth candidates has increased 140 percent since February 2011.  This bodes very well indeed for our future search for life in the galaxy.

The discovery of Kepler-22b as an Earth-like planet in a habitable zone is encouraging, but that by itself offers limited hope in our search for life elsewhere in our galaxy.  So far, all we know is that Kepler-22b is a smallish planet in orbit around a star like our Sun at a distance that is very promising.

It made be rocky, like the Earth, or it may be gaseous, like Neptune, but for us to know the true promise of Kepler-22b, we need to keep looking.  Keep collecting information with as many instruments as we can bring to bear.

Because it's what we DON'T know about Kepler-22b that offers us the most promise.