Sunday, April 20, 2014

WASP-43 b

It may not be much to look at, but I think this is the most mind-blowing thing I have been able to capture with my telescope.

260 light years away, around a nondescript 12-magnitude orange star in the constellation of Sextans, orbits a "hot Jupiter".  This planet, called WASP43 b, is the same size as Jupiter and twice its mass.  But it orbits very very close to the star - about 2 million km, 1/25 the distance of Mercury.  This close, it orbits about once every 22 hours. 

What this graph records is the brightness of the star in a series of 1 min exposures I took over three hours last night.  The magnitude is listed on the left - you can see the variations are between about 11.83 to 11.88, only 5/100ths of a magnitude.  A real test of equipment and technique.

The big dip in the graph is a transit - the tiny reduction in starlight when the planet passed in front of the star. The whole transit lasted about 1.2 hours. 

I remember going to Sydney Observatory in 1979, for my twelfth birthday party.  I asked the astronomer whether we would ever be able to see planets in other solar systems.  "No way" he replied "not unless we build huge telescopes on the moon".

Well, actually, just 10", on my balcony :-)

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