Date: February 18, 2011
Title: Finding Exoplanets, Part 4
Podcaster: Thomas Hofstätter
Contact: If you have any questions, comments or suggestions to the podcast, feel free to write me an email to hidden-space (at) gmx (dot) at or visit me at my website at www.hidden-space.at.tf!
Description: This podcast discusses the topic of Exoplanets and life on other planets out of our solar system.
Bio: Born in 1993 near Vienna, Austria, Europe. Upper High School with focus on Computer Science.Interested in extreme small and extreme big, devious and uninvestigated things. My main aim is to bring astronomy to public and to establish secular interest in astronomy, physics and mathematics. Host of :: The Hidden Space Project :: at http://hidden-space.at.tf.
Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by the Physics Department at Eastern Illinois University: “Caring faculty guiding students through teaching and research” at www.eiu.edu/~physics/
Transcript:
Hello and welcome to this episode of 365 Days of Astronomy. My name is Thomas Hofstätter and I am the hoster of :: The Hidden Space Project :: at www.hidden-space.at.tf.
[Leon:] And I’m Leon Dombroski from the state of Connecticut in the United States.
In this and other episodes we are going to talk about Exoplanets. We will have a look at the origin of thinking of life in other planetary systems as well as the science and technology behind the discovery of planets like in our own solar system.
All the previously discussed technologies useful for detecting exoplanets don’t observe the planet directly. They just measure its influences on the star or other objects located in the closer area. The most complex method, indeed, is to take a direct photo of a planet orbiting another star in its planetary system.
[Leon:] The main problem at this method is the fact that the star is shining quite bright in contrast to the planet that’s not shining anyway but just reflecting or absorbing the energy coming from the star. That concludes that the telescope on the one hand has to dim the light of the star and on the other hand has to be quite sensitive to be able to measure the small amounts of light reflected by the planet.
Another problem is the fact, that a planet usually orbits very close to its star (in relation to the distance from the star to us). As a result, a telescope photographing extrasolar planetary systems has to have a very high resolution to be able to show the planet separated from the glare of its star.
[Leon:] The first telescope able to take two separate images of an exoplanet was – as so often is the case – the Hubble Space Telescope. On November 13, 2008, the first direct measuring of an exoplanet orbiting around the star Fomalhaut in the constellation Piscis Australis has been announced. The star lies about 25 light years away from earth and has an enormous protoplanetary disk around it.
Looking at the star, you can notice the disk of debris spanning 21.5 million miles. A special feature is also that this disk forms a ring with a sharp inner edge. The found planet, now named Formalhaut b, is located at this edge.
[Leon:] Scientists used the Advanced Camera for Surveys at the Hubble Space Telescope to take two different images, one in 2004 and one in 2006 that even show the moving of the planet is what allows scientists to estimate the exact path of its orbit around the star.
Only some hours after the historic find of the Hubble Space Telescope has been released, the Gemini and Keck observatories announced having found the first “exoplanetary family”. They even had directly measured light of three planets around the star HR 8799.
[Leon:] They also had taken data in 2004 and then were able to measure two objects they thought could be planets. After observations in 2008, they even had evidence for a third planet orbiting the star. But the system is not comparable to our solar system. The planets orbit their host star in distances of 25, 40 and 70 times the distance between the sun and earth. The star is also a half more massive than our sun and 5 times brighter. Moreover, it’s younger than our sun.
All in all, there haven’t been many planets measured directly, yet. Also the brand-new Kepler Space Telescope that is specialized on the finding of exoplanets, doesn’t try to directly measure light from the planets but investigates planets that transit around its star. At the time, the Kepler spacecraft has detected 7 planets. But information has been leaked that Kepler has found several hundred planets from which some are even earth-like.
That’s it for today. I hope, you enjoyed it. If you have any questions, comments or suggestions, write me an email to hidden-space (at) gmx (dot) at or visit me at my website at www.hidden-space.at.tf.
Thanks for listening and clear-skies!
[Leon:] Good bye for now!
That’s the last podcast on the series on exoplanets. Find the other podcasts at www.hidden-space-podcast.at.tf.
End of podcast:
365 Days of Astronomy
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