While our Sun wanders through the galaxy with only its retinue of planets, comets and asteroids in tow, most of its siblings are found in multiple star systems. Systems with two, three or more stars are rather common. Indeed, our closest neighbor, Alpha Centauri, is a triple system with two stars (one similar to our own Sun) orbiting rather close to one another, with a smaller red dwarf star circling a comparatively greater distance away.

In the Star Trek: Voyager episode "Drive," Terrellian racer Irina tells Harry Kim that she's from a small trinary system, prompting Harry to remark, "Three suns. Must make for some long days." But is it really possible for life to have evolved in a three-star system?

While nearly a hundred extrasolar planets have been found to date, they have been found orbiting either single stars, or within multiple systems where the main stars are very far apart. As such, the stars in these multiple systems are far enough apart so as to be acting more-or-less independent from one another with respect to the objects that orbit them.

When stars get much closer to one another, the gravitational dynamics get more complex. Many astronomers had even wondered whether such star systems would even allow planets to form, much less remain in stable orbits for long periods of time. This led to some doubt that the nearest star system — Alpha Centauri — could have planets.

An announcement was made this week that raises the prospect of many more planets in the universe, and thus the possibility that we have more neighbors than had been previously suspected.

Astronomers with the McDonald Observatory Planet Search Project have discovered a planet 1.76 times the size of Jupiter orbiting the larger star of the binary star system Gamma Cephei once every 2.5 years. The planet orbits at a distance slightly greater than the orbit of Mars around our Sun. The Gamma Cephei star system is located 45 light-years from ours in the constellation Cepheus. (Illustration courtesy of McDonald Observatory)

The primary star is 1.59 times as massive as our Sun while its much smaller companion orbits 25 to 30 A.U. away — a hundred times closer than has been previously observed in planet-bearing multiple stars systems. (An A.U. is an "Astronomical Unit," the distance of the Earth from the Sun — approx. 93 million miles.)

Since stable orbits — and stable environmental conditions — for billions of years are probably required for intelligent life to evolve on a planet, this question has a direct bearing on the number of inhabited worlds we can expect to find. While the planet in the Gamma Cephei system is much, much larger than our own, it does provide proof that planets can reside in close binary systems for long periods of time.

Now all we need to do is refine our planet-hunting skills to find Earth-like ("Minshara-class") planets. Our next-door neighbor might be a good place to start — given that Irina's home is all the way on the other side of the galaxy. (Besides, Zefram Cochrane needs a place to retire.)

ISS Science Officer update:

Several weeks ago I reported on the naming of International Space Station (ISS) Expedition Five Astronaut Peggy Whitson as NASA's first 'Science Officer'. Well, it would seem that the Star Trek connection to this title was not lost on Peggy's friends and co-workers at NASA.

Peggy writes a regular letter from space. In her most recent letter she ended with:

"Mr. O'Keefe also came to Mission Control in Houston a couple of weeks ago and announced that I was to be the first Science Officer of the ISS. I obviously don't mind the new title, in spite of the fact that my many supportive friends have sent an incredible amount of Star Trek/Mr. Spock-related email!
Live Long and Prosper,
Peg"

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