August 18, 2009

The Big Dipper and Exoplanets

Big Dipper ExoplanetsAs of today, August 2009 the total number of known exoplanets stands at 373. Almost every month or every week, there are new exoplanets being discovered.
Pretty soon, exoplanet discoveries will be a regular occurrence that it becomes an ordinary thing. After all, exoplanets may be as "common as table salt", and they are numerous as grains of sand on the beach.

And then people might begin to lose the wonder of it all.

Amidst the accelarating rate of discoveries, I hope that we never lose that sensawunda. That is why it is important to know the exoplanets in the skies. We must be able to point at the stars and say to someone, "Look! Right there is another world!"

What better way to start with the exoplanets in the most-recognized pattern in the night sky--The Big Dipper. The Plough or the Big Dipper is an asterism that is a part of the constellation called Ursa Major. As you stare at the Big Dipper, you may actually be gazing at exoplanets as well. Light that passed through the horizon of another world may actually reach your eyes. Feeble as they may be, the photons of light from other stars carries information about the planets they harbor. Light is the medium by which scientists examine the atmosphere of other worlds. Of course they use instruments that are a millions of times more sensitive than our eyes. And these photometric instruments gather starlight far more efficient than our retinas.

Within the field of view of that big scoop in the sky, there are currently ten eleven exoplanets (as of 03/09/2010) discovered so far. Well, none of these "Big Dipper Exoplanets" orbit the stars of the actual Big Dipper shape, but they belong to the stars within the Ursa Major constellation. We simply use the Big Dipper as a guide.

Among the noteworthy ones of these "Big Dipper Exoplanets" are 47 Ursae Majoris b, the first exoplanet to be discovered within Ursa Major in 1996. It was followed by it's sibling 47 Ursae Majoris c in 2001. Their parent star with a magnitude is 5.1 is visible with the naked eye. Then there's HD 80606 b, a superjovian planet with the most highly-eccentric orbit known so far. HAT-P-3 b is the easiest to find as it lies near Alkaid, the tip of the Big Dipper's handle. HD 118203 b lies close to it near the first joint of the handle.

The rest of them is scattered away from the plough. More information can be accessed with a link via the list below. A KMZ file is also provided for use via Google Sky. And a data set view is set up in Freebase such that any new exoplanet entered with a constellation value of Ursa Major will be automatically included in that data view.

Although at this time the list is tiny, we can expect this list to grow in the coming years. Perhaps the Big Dipper may become so full of exoplanets that it wouldn't be big enough to contain them all.