The Astrophysical Journal

For The First Time Ever, Astronomers Have Observed a Black Hole Ejecting Matter Twice

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Black holes don’t just sit there munching away constantly on the space around them. Eventually they run out of nearby matter and go quiet, lying in wait until a stray bit of gas passes by.

Then a black hole devours again, belching out a giant jet of particles. And now scientists have captured one doing so not once, but twice – the first time this has been observed.

The two burps, occurring within the span of 100,000 years, confirm that supermassive black holes go through cycles of hibernation and activity.

It’s actually not as animalistic as all that, since black holes aren’t living or sentient, but it’s a decent-enough metaphor for the way black holes devour material, drawing it in with their tremendous gravity.

But even though we’re used to thinking how nothing ever comes back out of a black hole, the curious thing is that they don’t retain everything they capture.

When they consume matter such as gas or stars, they also generate a powerful outflow of high-energy particles from close to the event horizon, but not beyond the point of no return.

“Black holes are voracious eaters, but it also turns out they don’t have very good table manners,” said lead researcher Julie Comerford, an astronomer at the University of Colorado Boulder.

“We know a lot of examples of black holes with single burps emanating out, but we discovered a galaxy with a supermassive black hole that has not one but two burps.”

The black hole in question is the supermassive beast at the centre of a galaxy called SDSS J1354+1327 or just J1354 for short. It’s about 800 million light-years from Earth, and it showed up in Chandra data as a very bright point of X-ray emission – bright enough to be millions or even billions of times more massive than our Sun.

The team of researchers compared X-ray data from the Chandra X-ray observatory to visible-light images from the Hubble Space Telescope, and found that the black hole is surrounded by a thick cloud of dust and gas.

“We are seeing this object feast, burp, and nap, and then feast and burp once again, which theory had predicted,” Comerford said. “Fortunately, we happened to observe this galaxy at a time when we could clearly see evidence for both events.”

That evidence consists of two bubbles in the gas – one above and one below the black hole, expulsions particles following a meal. And they were able to gauge that the two bubbles had occurred at different times.

The southern bubble had expanded 30,000 light-years from the galactic centre, while the northern bubble had expanded just 3,000 light-years from the galactic centre. These are known as Fermi bubbles, and they are usually seen after a black hole feeding event.

From the movement speed of these bubbles, the team was able to work out they occurred roughly 100,000 years apart.

So what’s the black hole eating that’s giving it such epic indigestion? Another galaxy. A companion galaxy is connected to J1354 by streams of stars and gas, due to a collision between the two. It is clumps of material from this second galaxy that swirled towards the black hole and got eaten up.

“This galaxy really caught us off guard,” said doctoral student Rebecca Nevin.

“We were able to show that the gas from the northern part of the galaxy was consistent with an advancing edge of a shock wave, and the gas from the south was consistent with an older outflow from the black hole.”

The Milky Way also has Fermi bubbles following a feeding event by Sagittarius A*, the black hole in its centre. And, just as J1354’s black hole fed, slept, then fed again, astronomers believe Sagittarius A* will wake to feed again too.

The research was presented at the 231st meeting of the American Astronomical Society, and has also been published in The Astrophysical Journal.

Hubble Spots Odd Asteroid With Six Tails.

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Silly asteroid, tails are for comets! Around five months ago, an asteroid called P/2013 P5 was seen to be kicking off dust, making it look like it had a tail like a comet. Use of more detailed imaging would show that the asteroid actually has an unprecedented six tails.

In August, researchers had noticed P/2013 P5, an asteroid with a nucleus 1400 feet (427 meters) long, looked somewhat blurred through the Panoramic Survey Telescope & Rapid Response System (Pan-STARRS). Traditionally, asteroids appear as a sharp point of light, and this anomaly piqued the curiosity of the researchers. They figured that it might have begun rotating extremely quickly, causing it to kick off some of its surface dust and look like a comet.

On September 10, the team used the Hubble Space Telescope to get more detailed images of the oddball asteroid. The results completely dumbfounded the researchers: the asteroid had six tails that jut out in all directions, like spokes on a bicycle wheel! Even more amazing was the fact that when the team looked at it again less than two weeks later, the tails looked completely different.

After extensive analysis, it was determined that the tails are most likely the byproducts from six different dust-ejection events that were pulled out like tails by solar radiation pressure. That pressure is also believed to be what caused the asteroid to begin spinning so quickly in the first place, in a phenomenon known as radiation torque. If an asteroid is spinning too fast, its small amount of gravity is not enough to hold itself together and the dust goes flying off. Because the dust pattern does not suggest that a lot of material was ejected from the asteroid at once, the researchers are currently discounting the idea that these tails are the products of a collision. The results were published in Astrophysical Journal Letters.

So far, only a small percentage of its mass has been sloughed off into the tails, but this could be the beginning of the end for the asteroid. Future analysis will show if the dust is being ejected around the asteroid’s equator, which will be the best evidence that the asteroid is in the process of a rotational breakup.

While this is the first six-tailed asteroid that has ever been documented, researchers are confident that if there is one, there are probably many more waiting to be discovered.

– See more at: http://www.iflscience.com/space/hubble-spots-odd-asteroid-six-tails#sthash.QARL11oh.dpuf

Plastic ingredient spied on Titan.

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Cassini probe sees plastic ingredient on Titan moon

 

Titan

 

 

The Cassini probe has detected propene, or propylene, on Saturn’s moon Titan.

 

On Earth, this molecule, which comprises three carbon atoms and six hydrogen atoms, is a constituent of many plastics.

 

It is the first definitive detection of the plastic ingredient on any moon or planet, other than our home world, says the US space agency (Nasa).

 

The discovery, made by Cassini‘s infrared spectrometer, is reported in Astrophysical Journal Letters.

 

“This chemical is all around us in everyday life, strung together in long chains to form a plastic called polypropylene,” said Conor Nixon, a Nasa planetary scientist from the agency’s Goddard Space Flight Center. A classic example would be the plastic boxes used to store food in kitchens worldwide.

 

Titan is dominated by hydrocarbons – principally methane, which after nitrogen is the most common component of the atmosphere.

 

Sunlight drives reactions that break apart the methane, allowing the fragments to join up and form even bigger molecules.

 

Other common species seen at the moon as a result are propane, which on Earth is used in portable cooking equipment, and ethane, which is the raw material for another ubiquitous plastic – polyethylene.

 

But the likes of methane, propene, propane and ethane are dwarfed by some truly colossal hydrocarbons that have been detected in Titan’s atmosphere.

 

When the effects of ultraviolet light are combined with the bombardment from particles driven in Saturn’s magnetic field, it becomes possible to cook up some very exotic chemistry.

 

Cassini’s plasma spectrometer has seen evidence for hydrocarbons with an atomic mass thousands of times heavier than a single hydrogen atom.