Gregory Laughlin studies massive extrasolar planets

Image Credit: NASA

In 2005, astronomers found a planet in a distant solar system that has an extremely large solid core. The core is some 70 times more massive than Earth! HD149026 b confirmed a planet formation theory. It became one more on a list of ‘jupiters’ in other solar systems sought by a consortium of American, Japanese and Chilean astronomers.

In 2005, astronomers found a planet in a distant solar system that has an extremely large solid core. The core is some 70 times more massive than Earth! HD149026 b confirmed a planet formation theory. It became one more on a list of ‘Jupiters’ in other solar systems sought by an international consortium of astronomers.

At one time, the only planets we knew were those in our own solar system.

But, over the past decade, astronomers have discovered over 150 planets orbiting distant stars. Gregory Laughlin is an astronomer at the University of California Santa Cruz. He’s part of an international consortium that’s surveying 2,000 stars with the hope of finding perhaps 60 more hot Jupiter-sized planets.

Gregory Laughlin: What we were interested in doing is trying to find more planets, and in particular trying to find planets that have their orbits aligned so that they transit in front of the parent star. Because when a transit occurs, then you can measure the actual mass of the planet, and you can measure the actual size of the planet. And by measuring the size of the planet, and comparing that to theoretical calculations, you can get information about what the planet’s made of.

Laughlin and his colleagues recently announced the discovery of an extrasolar planet with the largest solid core ever found. It’s thought to be composed of mostly ice and rock from untold millions of comets, which formed first as an Earth-sized core – that built itself up from the inside out.

Called HD 149026 b, the planet is roughly equal in mass to Saturn, but it is smaller in diameter than the ringed planet. This distant world takes just 2.87 days to circle its star, in contrast to a year for Earth!

Computer modeling of the planet’s structure shows it has a solid core approximately 70 times Earth’s mass. This planet discovery is the first observational evidence that proves a major theory of planet formation, called the ‘core accretion’ theory.

Thanks today to Research Corporation, a foundation for the advancement of science.

Our thanks to:
Gregory Laughlin
UC Santa Cruz