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Ken Hose
"Exoplanets and the Search for Habitable Worlds"
July 18,2011

June's speaker will be our own Ken Hose, talking about the search for Exoplanets and his own research from his home observatory near Wilsonville, Oregon.

In 1995 the first extra-solar planet was discovered by detecting the small “wobble” of the host star induced by the orbit of the planet. Since then the number of confirmed planets has increased dramatically to over 500 to date with hundreds more to be announced soon. The characteristics of some of these solar systems have surprised astronomers because they are so different from our own. About one-third of the planets detected so far are about the size of Jupiter with orbital periods of just a few days.

Findings like this have caused scientists to re-think how planetary systems form and evolve. One of the main science goals is to find earth-like planets in the habitable zones around their stars. This is the stated goal of NASA’s Kepler Mission. Data from Kepler and other searches will help us estimate the distribution and types of planets in our galaxy and how many planets could potentially harbor life. Most of the planets detected are very large and massive because they are the easiest to detect.

The detection technology is evolving and it will become easier to detect earth-size and smaller planets in the future, especially with space-based equipment.

Ken Hose developed an interest in extra-solar planets two years ago when he found out that some can be detected using amateur-grade equipment.

He will review what scientists have learned so far about these planets and the different detection techniques used to find them.

He will also cover how improvements and evolution in detection methods will make it easier to find earth-sized planets and how scientists hope to learn more about composition of the planets and their atmospheres.

Finally, he will have a few words about several known planets he has been able to detect from his backyard observatory.

This is a plot done by Ken from his home observatory of the entire transit of TrES-3b. The planet is larger than jupiter (1.3 Rj) and orbits around a G-type star, GSC 3089:929.

His measurements compared fairly well with predictions. From the amount of dimming we can deduce that the radius of TrES-3b is about 0.163 x the radius of its host star.

Since the transit only lasted about 77 minutes, the planet orbits very close to its host. He used a series of 100-second exposures with a red filter and a 12.5" RCOS scope.

The imaging camera was a QSI 516wsg with a ST-402 guide camera. He extracted the photometric data using MaxIm DL. He used the on-line ETD-Exoplanet Transit Database to curve-fit the data and extract the figures of merit.

Seeing was pretty good with an average of about 2.5" or so.



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