Roughly half of all the points of light in the night sky are actually binary star systems, in which two stars orbit around a common gravitational midpoint. This is a handy feature of the universe for astronomers, because while the properties of a lone star cannot easily be discerned, stars doing the do-si-do can, with recent advances in technology, be weighed and measured to some extent.

Using one of these advanced techniques, called adaptive optics, a team of European researchers has only weighed a pair of stars but they've produced an animation that reveals how they orbit one another.

The stars rotate around each other in just three days. As seen from Earth, two "eclipses" occur on each orbit. An eclipse happens when one star passes in front of the other, as seen from our view. The fact that these eclipses can be seen means that the stars orbit in a plane of space that is edge on, as seen from Earth.

During each eclipse, the light of one star is partly blocked, causing the total light coming from the system to drop. That drop in starlight provides much of the evidence needed to study the stars.

By analyzing the drop in starlight and the motions of the two stars, astronomers were able to determine the masses of each one. They are about as heavy as our Sun.

But while the Sun is about 4.5 billion years old, these two stars are still in their infancy. They are located some 1,500 light-years away in the Orion star-forming region, and researchers believe they formed just 10 million years ago.

The more massive of the two stars is also the hotter and brighter one of the pair. Its mass is 1.3 times that of our Sun. It is nearly 1.6 times larger than the Sun and the surface temperature is found to be a little more than 5000 degrees Celsius, or a few hundred degrees cooler than the Sun.

The "secondary" star weighs about 90 percent as much as the Sun. Its diameter is 20 percent larger, while the surface temperature is 4000 degrees.

This is the first time such an accurate determination of the stellar masses could be achieved for a young binary system of low-mass stars, say the European scientists who did the study. They say the new result will add important information to the puzzle of how young stars evolve.

The binary star system is officially called RXJ 0529.4+0041. The astronomers report that they also noted the presence of a third star in the system.

The observations were made by astronomers from Italy and the European Southern Observatory, using a 3.6-meter telescope at the La Silla Observatory, in Chile. The telescope adjusts for blurring effects of the atmosphere, which would otherwise reduce its resolving ability. The research was led by Elvira Covino of Osservatorio Astronomico di Capodimonte in Napoli, Italy.