Posted on 06/01/2007 8:22:19 PM PDT by Moonman62
Using a suite of four telescopes, astronomers have captured an image of Altair, one of the closest stars to our own and a fixture in the summer sky.
While astronomers have recently imaged a few of the enormous, dying, red-giant stars, this is the first time anyone has seen the surface of a relatively tiny hydrogen-burning star like our own sun.
"The galaxy is shaped by the effects of relatively rare but powerful hot, rapidly rotating stars," says John Monnier of the University of Michigan, the lead author on the study that will appear on Science Express on May 31, 2007. "These stars have more in common with Altair than our own sun and understanding Altair will allow us to better understand how these influential stars scattered throughout the galaxy operate."
Monnier was part of an international team of astronomers that captured the image using four of the six telescopes at a facility on Mt. Wilson, Calif., operated by the Center for High Angular Resolution Astronomy (CHARA) at Georgia State University in Atlanta with partial support from the National Science Foundation (NSF).
The CHARA telescopes were able to make the breakthrough observation because they were outfitted with a novel system to clean up some of the distortions from Earth's atmosphere, a technology called the Michigan Infrared Combiner, developed with NSF support at the University of Michigan in Ann Arbor. Recent advances in fiber optic telecommunication technology made this new combiner possible.
"For looking at optical or infrared wavelengths of light, the CHARA telescope array has the world's longest spacing between telescopes and therefore the greatest ability to zoom in on the stars," adds Hal McAlister, CHARA director and a professor of astronomy at Georgia State.
Until now, astronomers could gather tremendous amounts of data from stars, but could not capture images of what the stars looked like. Even to the largest telescopes, stars looked like the points of light we all see when we peer up into the night sky.
Using the telescopes as an interferometer--a multi-telescope system that combines information from small, distantly spaced telescopes to create a picture as if taken from one large telescope--the researchers captured infrared lightwaves as if from a giant telescope 265 meters by 195 meters in dimension (100 times the size of the mirror on NASA's Hubble telescope and roughly 25 times the resolution).
"Without the interferometer, the ability to obtain such detailed images would not be possible with today's existing telescopes--or even the planned 30-meter telescopes," says Julian Christou, one of the NSF officers overseeing the research. "The critical component of the CHARA system is the beam combiner which allows the light from the individual small telescopes to be mixed together, which up to now had only been successfully used with radio telescopes such as the Very Large Array near Socorro, N.M."
The discovery is helping to answer questions about stars while raising others, particularly when researchers compare long-standing models to the new observations.
For example, Altair is a speedily spinning "rapid rotator", just like Vega, one of Altair's partners (with the slow-spinning supergiant Deneb) in the Summer Triangle in the night sky.
Altair spins so quickly, about 300 kilometers per second at its equator, that it's shape is distorted: the star is a full 22 percent wider than it is tall. The new telescope measurements confirmed the oblong shape, yet showed slightly different surface temperature patterns than what models predicted.
Altair is one of the closest stars in our neighborhood, only about 15 light years away, and the researchers hope to image Vega as well as more distant stars in the future.
"Imaging stars is just the start.We are going to next apply this technology to imaging extrasolar planets around nearby stars," said Ming Zhao, an astronomy graduate student at Michigan who carried out the detailed stellar modeling.
NSF supported this research through awards 0606958 and 0352723, along with a number of awards totaling nearly $6.5 million to help construct CHARA.
For additional information, see the press releases at the University of Michigan (http://www.umich.edu/news/) and Georgia State University (http://www2.gsu.edu/~wwwexa/news/).
Additional graphics are available at: http://www.astro.lsa.umich.edu/~monnier/Local/altair2007.html
-NSF-
Hard to argue with someone who doesn't know the difference between emission and absorption spectra. If fusion isn't taking place, then what causes the observed neutrino flux (with improved detectors which have detected the flux predicted by stellar fusion models)?
Gravitational contraction cannot power the observed energy output on time-scales consistent with other observational data. So I ask, what, other than fusion processes, could be the source of the solar energy? Invisible Unicorns running around in giant hamster wheels inside the sun, farting neutrinos in just the right amounts to fool us?
Yup, another Purveyor of Unknowledge has spoken....
Then you should have no trouble posting some of that evidence.
And I am sure that evidence will live up to the standards of evidence that you require of science.
May I join the group?
Shame on you.
I hadn't even gotten to the parts about the silk rope and the Chinese gunpowder.
How's a lad going to get an education if you intimidate him like that?
How do we even know it's burning, right? I mean, there's no oxygen!
Listen, I'm not going to sit here and argue with you people. If intelligent questions annoy you and critical thinking evades you that is your problem. I'm happy living in the real world.
I was taught that all fires require oxygen to burn. There are 3 compenents to a fire - eliminate one and no more fire:
1. Fuel.
2. Oxygen.
3. Heat.
That’s as real world as I know. Am I missing something?
Look, I really don't want to argue. There are many substances that we do know about that do not need oxygen to burn and not knowing everything there is to know I am relatively certain most, if not all of us have no clue what type of materials there are yet to be discovered that can burn without Oxygen. It's the height of arrogance for these bone headed eggheads to state something as a fact when they don't know their rear ends from a hole in the ground.
Be well!
One must ever be cautious not to make a misstatement.
"There are many substances that we do know about that do not need oxygen to burn and not knowing everything there is to know I am relatively certain most, if not all of us have no clue what type of materials there are yet to be discovered that can burn without Oxygen."
And who can argue with that? -- By any chance, will you be entertaining all week?
You are incorrect, sir. Fires require Oxygen. And I will stop pinging you about it if you are done with the subject.
Nope.
Plants recycle Oxygen, separating it from Carbon Dioxide by utilizing solar energy during photosynthesis.
Oxygen is created in stellar furnaces through thermonuclear fusion. It gets distributed through the galaxy when stars called supernovae explode.
Even if oxygen were to combine chemically with hydrogen or carbon in the sun, it would rapidly disassociate once again because of the extreme heat. The gases in the sun are a plasma, such as may be seen in a welder's electric arc just before you go blind.
That's a correct description of fire. But what fuels the sun is not ordinary fire.
The sun combines hydrogen with hydrogen in a process that produces energy because there is just the slightest amount of mass that disappears according to the famous equation, E=mc2.
The amount of energy from any particular combination may not amount to much, but the sun goes through a lot of hydrogen.
You can perform the calculation for yourself. Find the amount of energy that is falling on a unit area at this distance from the sun. Multiply that by the amount needed to fill a spherical volume of space at the same radius.
You will find that the equivalent energy is equal to the disappearance from existence of four million tons of hydrogen every second!
As I said, the sun goes through a lot of hydrogen. And yes, eventually it will run out of it ... in about five billion years.
LOL -- And you know this how?
Look guys. I told you I'm not going to argue with you. Junk-Science and I don't get along. I like actual physical proof. You may like your proof to be on the rather vague and cloudy side but me... Well I like it to be rock solid and indisputable. It is obvious that you all enjoy vain babblings and wonderland. I do not. I simply asked a question that has yet to be answered and you all have attacked me for asking it.
Grow up!
How would you go about gathering physical proof of a plasma?
It is called the fourth state of matter; solid, liquid, gas, and plasma. But it isn’t exactly rock-solid.
Forgive me but I'm tired of egg-heads stating as fact "theories." Theories are nothing more than glorified hunches and until actual evidence (like a physical sample of the material burning on the Sun collected off the Sun) that's all this "hunch" will be.
You might be surprised what a bunch of "egg-heads" can do. If it wasn't for the "egg-heads" of this country, we'd probably be a Russian satellite state, as they would have gotten the atom bomb first (An man named Arthur Eddington figured that the Sun an off shoot of the atom bomb research is one of that ways how we know what reactions power the sun).
One of the things that chemists and astrochemists have been doing for the past 70 years is understanding chemical reactions. The idea that nucleosynthesis of elements in the universe comes naturally from the stellar lifecycle (and from the Big Bang) comes straight from observations that scientists have been gathering from laboratories right here on earth.
We can tell exactly the composition of the Sun and other stars from their spectra obtained through telescopes, and those observations are well known, having been directly observed in labs all over the planet back in the 1920's and 30s (indeed, they can now be verified in labs that are taught in Astro 101 class in every College and University on the planet, and in an exhibit in the Nat'l Air and Space Museum in DC). We know all about what exists between here and the sun because we have had satellites such as SOHO and other satellites observing the Sun and the planets at every concievable direction that you can think of. We can use physics and chemistry obtained experimentally along with basic observables (like density and temperature) to determine boundary conditions of the environment at the surface of the Sun. With that and a knowledge of what fusion reactions are possible at what range of temperatures (which are derived from theoretical physics and chemistry), it's pretty simple to understand what's going on inside a star, and much of the work was done in this field long before the development of the modern personal computer (i.e. before 1975). A Nobel Prize in Physics was given to Willam Fowler in 1983 for his work done in this field back in the 40's and 50's This stuff is about as well known as you can get without actually building a star in your backyard.
If you can't deal with deductive reasoning and logic, then don't ever set foot into a jury box, you wouldn't believe they things they try to sneak by you with that stuff in a trial.
Sheeez people. If you wish to worship yourselves go for it but stop addressing me k?
Thanks.
placemarker
You really should deploy your ping list. Your guy’s on a roll.
I don’t know why Joseph Lockyer’s voyage is not more well known. I can only suppose it is due to persecution of news reporters and scientists by the solar phlogiston contingent (who, as you recall, broke into Lockyer’s lab and destroyed his notes, and spread rumors that he was mad). While they were not able to suppress Lockyer’s discoveries entirely, the story of his solar voyage has sunk into obscurity.
I certainly hope so. I wouldn't begrudge him much if he charged admission.
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