18 Jun 2009

Extra-solar Planets

From Our Changing World, 9:20 pm on 18 June 2009

by Veronika Meduna

The MOA telescope at the Mt John Observatory

The 1.8m MOA telescope at the Mt John Observatory was installed in 2003 and began observing in 2004.

The first planet outside our own solar system was discovered in 1988, and in the two decades since then, more than 350 new extra-solar planets have been added to the list. The largest telescope at the Mt John Observatory near Lake Tekapo is used to search for stars that have planets orbiting around them, using a method called gravitational microlensing, which was first described by Albert Einstein. MOA (Microlensing Observations in Astrophysics) is a Japanese/New Zealand collaboration which also contributes to fundamental research on dark matter and stellar atmospheres.

This technique makes use of the magnifying effect of stars that line up behind each other. The front star acts as a lens for the more distant star, and if the front star has planets orbiting around it, they will cause wobbles in the magnifying effect. The advantage of this technique is that it is more sensitive to less massive and more earth-like planets in distant regions of the galaxy.

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