Posts Tagged ‘telescope’

Carbon Dioxide Found on New World

Monday, December 15th, 2008 by Bellatrix

It’s no new thing to find a planet these days since we’ve detected hundreds of extrasolar planets by now. Now being able to determine the chemicals present on other planets, now that’s pretty new and exciting. Now for the first time carbon dioxide has been detected on a planet outside of our solar system.

The planet is called HD 189733b and lies about 63 light years from us. It’s a large planet, about the size of Jupiter with a very short rotation period of only 2.2 days. Astronomers have been observing the planet for a while now using both the Hubble Space Telescope and Spitzer Infrared Space Telescope. Last year they discovered water vapor and then some time later methane. But this is the first time an organic compound such as this has been found on another world. Now this planet is too hot to support life, but chemicals like this one are by products of life processes thus when we are able to start detecting earth sized planets this may be an indirect way of discovering other life forms.

It is exciting not just knowing that these other planets are there but we’re actually able to say something about them. Using the Hubble Near Infrared Camera and Multi-Object Spectrometer (NICMOS) to study the infrared light emitted by the planet. Gases in the planet’s atmosphere absorb certain wavelengths of light from the planet’s hot glowing interior. The astronomers identified not only carbon dioxide, but also carbon monoxide. The molecules leave their own unique spectral fingerprint on the radiation from the planet that reaches Earth. This is the first time a near-infrared emission spectrum has been obtained for an exoplanet. With these detection techniques we can describe the conditions, chemistry, and atmospheric composition of other planets.

This planet was a good candidate for this type of study because of the orientation of the planet to Earth’s orbit. The planet’s orbit is facing us edge on, so when it moves around its star and the star eclipses it. So astronomers are bale to subtract out the light that is due only to the star and thus are left with the spectrum coming from the planet.

Once the new James Webb Space Telescope launches things will get even more exciting. Astronomers will be able to use this technique but with the much greater sensitivity of the new telescope hopefully it will be on terrestrial, or earth like planets. Until then astronomers will be using this technique to look at other exoplanets to see what other new things they can discover.

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Students Discover New and Different Planet

Monday, December 8th, 2008 by Bellatrix

Three undergraduate students from the Netherlands have made a new discovery in our universe without even trying. They discovered a new extrasolar planet, which is a great discovery itself, but to top it off they discovered it using a new technique and found it orbiting a special kind of star.

Students Meta de Hoon, Remco van der Burg, and Francis Vuijsje were given the assigned to develop search algorithms. They did so well on this project that they had time to test their search algorithm on real data. So they set to work investigating light fluctuations in thousands of stars in the so far unexplored OGLE database. The brightness of one of the stars was noticed to decrease by about 1% every two and a half days. The students were then allowed to use the ESO Very Large Telescope in Chile to follow up and confirm that a planet was causing the fluctuations.

The planet was given the name OGLE2-TR-L9b, but the students like to call it ReMeFra-1 after their names. The planet is quite large, weighing in at about five times the mass of Jupiter. To make sure that it was a planet and not a small star o brown dwarf they used spectroscopy to look at the chemical make up of the orbiting body and confirmed it is not a star. The planet is orbiting very close to its star; it lies at only three percent of the Earth-Sun distance giving it an orbital period of only 2.5 days. This discovery is also special because of the type of star. The star, named OGLE-TR-L9 is now the hottest star found to have a planet orbiting it. The star itself also rotates very quickly, which would have made it hard to use the conventional method of planet detection to find this one.

So we can add another extrasolar planet to the growing list. With each new planet discovery we learn so much. We have now expanded the list of possible stars that could have planets, knowing that stars this hot and fast can have planets. This technique may prove quite useful in detecting planets around similar stars. And the part that I think is most exciting is that this was all done by undergraduate students. Undergraduates are usually lucky to get some research experience, maybe a have a paper published with their names below their professor’s, but these students did something extraordinary and they’re getting the credit. It shows that you don’t have to be a stuffy know it all professor who has been researching for many years to be able to contribute.

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Double Checking Our Data

Wednesday, November 26th, 2008 by Bellatrix

Scientists believe they have found the answer to a mystery about a thought to be nearby galaxy. The funny thing is this answer was found by rather serendipitously after finding out our current estimates for the distance of the galaxy were wrong.

The galaxy named NGC 1569 was a bit of a mystery. It is an irregular shaped dwarf galaxy, which isn’t in itself strange, but the galaxy was going through a burst of star formation with no discernable reason. The galaxy was forming stars much faster than any other galaxies in its nearby region. Well then we realized that the problem with that statement was not NGC 1569 itself but the galaxies we thought were nearby it.

Scientists recently pointed the Hubble Space telescope at NGC 1569 to scan for red giant stars. The astronomers were hoping to get an estimate of the galaxies age by looking for red giants, as red giants can be used as reliable standard candles for measuring distance since they all burn at the same known brightness. However, the astronomers were only able to see the brightest red giants, even using Hubble, the stars were too dim to be resolved. This fact lead astronomers to question the previous estimate for how far away the galaxy actually is. And now after looking at the data astronomers have realized the galaxy is actually about one and a half times farther away than previously thought, making it about 11 million light years away.

The problem was before this the galaxy had only been studied with ground based telescopes, which have much less resolving power than space based telescopes, which can make estimates less accurate. With this new information the galaxy’s star formation makes more sense. This distance puts the galaxy in the middle of a cluster of ten other galaxies. The gravitational interaction of the galaxies tugging on each other would be enough to explain the high rate of star formation we see in this galaxy.

So using Hubble we have answered yet another question, good ol’Hubble. However, this instance makes one wonder how many other numbers that we have for things like distance or mass etc might be inaccurate after only being studied by ground-based telescopes. How many things should we go back over with space-based telescopes to make sure? And how many mysteries or unexplainable phenomena might be answered by simply rechecking our data??

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Very Large Binoculars; Not for Bird Watching

Monday, October 20th, 2008 by Bellatrix

Recently an exciting new type of ground-based telescope came online. It is a collaboration between the University of Arizona, the National Institute of Astrophysics in Italy, and several institutions in Germany. It is an innovative idea to use two large mirrors for the telescope, like a pair of binoculars. This will give the telescope a large collecting area while avoiding complications of making one very large mirror.

The idea first started back in 1992 between Arizona and Italy. They only had the funding to make one mirror, but in 1997 with the addition of Germany and Ohio State University, the project was under way. The telescope mount was constructed in Italy and shipped to Arizona, where it joined the mirrors being constructed. The observatory will be part of the Mt. Graham International Observatory near Safford, Arizona.

The telescope will consist of two 8.54-meter mirrors on a shared mount, which has the light gathering power equivalent to one 11.8-meter mirror and a resolving power of a 22.8-meter mirror. The building of the two mirrors is a delicate and complicated process. The mirrors must go through an extensive annealing and cooling process. Then two tons of glass are added and then a slow heating process started, then another round of annealing and cooling. During this process glass leaks are possible which can really complicate things. Once finished the mirror mold must be cleaned and polished very carefully and exactly. The mirrors must stay in a temperature-controlled environment to prevent temperature changes affecting the surface of the mirrors.

The first primary mirror saw first light in 2005, but it wasn’t until 2008 that both mirrors came online together. The optical instruments include a UV spectrograph, thermal infrared imager, near infrared camera, high-resolution optical spectrograph, optical direct imager, and more. The telescope is designed for observing in the UV, optical, and infrared wavelengths.

The Large Binocular Telescope observatory (LBT) is the world’s highest resolution and most technologically advanced optical telescope, creating images in the near infrared with 10 times the resolution of the Hubble Space Telescope. There should be some exciting new developments coming from the LBT once it really gets going. It is a great example of innovation and ingenuity to overcome the technological obstacles of making very large mirrors and by using an array of smaller (yet still large) mirrors.

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