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-
Interesting stuff.
Info bump.
Altair 4- The Forbidden planet!
We can see it.
What do you think it burns?
Ethanol
Yes, of course. Corn is the answer...
The Sun converts hydrogen in to helium and then that gets converted into higher molecules. We know this from spectrophotometer observation of the sun.
What’s really going to freak you out is we know what the interior of the Sun looks like.
I thought it was wax since it has the same color as the flame on a candle.
Ping
The only direct evidence we have of hydrogen fusion in the Sun is the solar neutrino flux, and it’s famously problematical.
It’s not as problematical as it used to be.
Don’t worry folks! Everything’s under control! As I understand it, they are leaning towards the “oscillating neutrinos” explanation. “It’s the physics, not the model.” I believe there are efforts underway to produce this effect experimentally.
It seems to be part of the general trend of “obscuram per obscurius” - ( explaining) “the obscure by means of the more obscure”. Cf. John Horgan’s book, The End of Science. He spoke to my condition.
That would explain your post.
“Neutrino oscillation is a quantum mechanical phenomenon predicted by Bruno Pontecorvo whereby a neutrino created with a specific lepton flavor (electron, muon or tau) can later be measured to have a different flavor. The probability of measuring a particular flavor for a neutrino varies periodically as it propagates. Neutrino oscillation is of theoretical and experimental interest as observation of the phenomenon implies that the neutrino has a non-zero mass, which is not part of the original Standard Model of particle physics.”
Plain as the nose on your face. Do you claim to understand this better than I do? ( I don’t claim to understand it very well, but I do understand the basic QM oscillation paradigm. )
Well, it’s “obscurum per obscurius”. This is in Foreign Words and Phrases in Webster’s Ninth Collegiate. I was quoting from memory, and I did recall the exact english paraphrase. Woof!
I have no idea what it burns and until someone can bring us back a sample of what it burns neither does anyone else on this planet.
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