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Scientists Spot Rare 'In Between' Black Hole
An anonymous reader writes "Scientists have found a doomed star orbiting what appears to be a medium-sized black hole. This black hole appears to be a theorized 'in-between' category of black hole that has eluded confirmation and frustrated scientists for more than a decade."
The link leads to some sort of science blog. An interesting discovery none the less.
Ah, you found me!
saved for posterity before it gets slashdotted
Dying Star Reveals More Evidence for New Kind of Black Hole
Submitted by BJS on Sun, 2006-01-08 11:58.
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Scientists using NASA's Rossi X-ray Timing Explorer have found a doomed star orbiting what appears to be a medium-sized black hole - a theorized "in-between" category of black hole that has eluded confirmation and frustrated scientists for more than a decade.
With the discovery of the star and its orbital period, scientists are now one step away from measuring the mass of such a black hole, a step which would help verify its existence. The star's period and location already fit into the main theory of how these black holes could form.
A team led by Prof. Philip Kaaret of the University of Iowa, Iowa City, announced these results today in Science Express. The results will also appear in the Jan. 27 issue of Science.
"We caught this otherwise ordinary star in a unique stage in its evolution, toward the end of its life when it has bloated into a red giant phase," said Kaaret. "As a result, gas from the star is spilling into the black hole, causing the whole region to light up. This is a well-studied region of the sky, and we spotted the star with a little luck and a lot of perseverance."
A black hole is an object so dense and with a gravitational force so intense that nothing, not even light, can escape its pull once within its boundary. A black hole region becomes visible when matter falls toward it and heats to high temperatures. This light is emitted before the matter crosses the border, called the event horizon.
Our galaxy is filled with millions of stellar-mass black holes, each with the mass of a few suns. These form from the collapse of very massive stars. Most galaxies possess at their core a supermassive black hole, containing the mass of millions to billions of suns confined to a region no larger than our solar system. Scientists do not know how these form, but it likely entails the collapse of enormous quantities of primordial gas.
"In the past decade, several satellites have found evidence of a new class of black holes, which could be between 100 and 10,000 solar masses," said Dr. Jean Swank, Rossi Explorer project scientist at NASA's Goddard Space Flight Center, Greenbelt, Md. "There has been debate about the masses and how these black holes would form. Rossi has provided major new insight."
These suspected mid-mass black holes are called ultra-luminous X-ray objects because they are bright sources of X-rays. In fact, most of these black hole mass estimates have been based solely on a calculation of how strong a gravitational pull is needed to produce light of a given intensity.
Kaaret's group at the University of Iowa, which includes Prof. Cornelia Lang and Melanie Simet, an undergraduate, made a measurement that can be used in the equation to directly calculate mass. Using straightforward Newtonian physics, scientists can calculate an object's mass once they know an orbital period and velocity of smaller objects rotating around it.
"We found a rise and fall in X-ray light every 62 days, likely caused by the orbit of the companion star around the black hole," said Simet. "The velocity will be hard to determine, however, because the star is located in such a dust-obscured area. This makes it hard for optical and infrared telescopes to observe the star and make velocity calculations. Yet for now, knowing just the orbital period is very revealing."
The suspected mid-mass black hole, known as M82 X-1, is a well-studied ultra-luminous X-ray object in a nearby star cluster containing about a million stars packed into a region only about 100 light years across. A leading theory proposes that a multitude of star collisions over a short period in a crowded region will create a short-lived gigantic star that collapses into a 1,000-solar-mass black hole. The cluster near M82 X-1 has a high-enough density to f
The parent comment was obviously intended as a joke. Maybe not a very good joke, but a joke, nevertheless. The off-topic mod is unfair as the poster is clearly making a joke with reference to the topic of the article (in-between black holes). Is there some sort of mechanism on /. to automatically mod down as off-topic any post with the word goatse somewhere in the title?
my pet machine
I think elements heavier than iron (the heaviest element that can be produced by fusion while making energy, rather than using it) are formed *during* the supernova, which only lasts a few seconds (or maybe hours/days - ask an expert - it doesn't matter though) and don't have time to fall to the centre because they're already exploding outwards - it's the explosion itself that produces them (pressure wave causes high density, causes fusion).
The key to creating heavy elements is a large neutron flux from the supernova. Nuclei pick up lots of neutrons quickly during a time span of a few seconds (shorter than the free neutron half life of 13 minutes) and then undergo a quick succession of beta decays followed by a longer beta decay series over millions of years to form stuff like gold and uranium.
Physics makes the world go 'round.
Here is the coral link http://www.scienceblog.com.nyud.net:8090/cms/dying _star_reveals_more_evidence_for_new_kind_of_black_ hole_9685
They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety.
In fusion, most things up to Iron can be produced.
Um. No. A fusion reaction can create any substance up to uranium and beyond. In fact, humans are continually creating substances beyond uranium (plutonium being one) through fusion reactions. It's just that fusion reactions to produce elements heavier than iron require energy, rather than giving off energy.
In the early stages of a star's life, it's fusing hydrogen atoms to produce helium. This is the most energetic fusion reaction, and is the only fusion reaction we're likely to be able to sustainably exploit to our own ends through artificial means. As the star grows older, and has less hydrogen, it will increasingly generate its energy through other fusion reactions, producing elements up to iron. (These reactions will occur throughout the star's life; it's just that they will become proportionally more important as the star ages.)
Eventually, the energy produced through these fusions will die off, and the star will undergo gravitational collapse. During this phase, the energy consuming fusion reactions will occur, generating the heavier-than-iron elements. This phase only occurs in massive supernova; it won't happen in our sun -- it's not big enough.
That's where the beta decay comes in. Beta decay turns neutrons into protons.
Happy people make bad consumers.
They reckon it's a massive black hole because it's bright. Black holes that give off a lot of light have to be massive, because of something called the Eddington Limit.
However, it's just a dot in the sky, you can't tell how much energy in total is being given out just by measuring how much is coming in the direction of Earth - you don't know if it's a 60W lightbulb shining in all directions or a 5W torch pointing at you. For instance, black holes can have jets (rather like pulsars) and a smaller black hole with a jet pointing at Earth could explain their observation.
Discovering that it has a star orbiting it every two months doesn't change any of that, as far as I can tell.
I quit!
OK. I am also an astrophysicist, and I have been studying gravity in its string theory and loop quantum guises. Gravitational waves carry information, so they will *not* come out of a black hole horizon. However, gravity (as expressed in the theory of General Relativity) obeys what is called Gauss's law, which just means to say that it doesn't matter (!) what lies beneath the spherical BH horizon, or *any* imaginary sphere that surrounds it, gravity only depends upon the total mass (or equivalent energy) contained within. No gravitons need escape the BH horizon to create the gravity equivalent to the mass gobbled up by the hole.
- GRR
This line no sig