Astronomers (probably) take 1st direct pix of planet orbiting star

William Atkins
Tuesday, 16 September 2008 18:54

Science - Space

The image taken by the astronomers is found on the National Geographic website “First Picture of Alien Planet Orbiting Sunlike Star?”

The astronomers state in the abstract to their paper, “If gravitationally bound, this would be the lowest mass companion imaged around a normal star thus far, and its existence at such a large separation would pose a serious challenge to theories of star and planet formation.”

Thus, the discoverers of the planet state there is a chance that the planet is not really a planet and is not “gravitationally bound” to the star. Instead, it could be just an astronomical body that is, by chance, in the same part of the sky as the star.

In this case, this discovery would not be the first image of an exoplanet orbiting a star other than the Sun. Further investigations will decide for sure.

However, if the planet is found to be orbiting the star, then its presence causes a problem to astronomers because it is too far out in its orbit according to currently accepted theories on planet formation.

Young stars, such as 1RXS J160929.1-210524 (which is estimated to be only about five million years old), evolve so that planets form very close to their parent star. However, the exoplanet hasn’t apparently formed very close to its sun.

Our Sun is about 4.56 billion years old, meaning it is an older star, and, according to theory, more apt to have planets located in orbits further away from it.

The astronomers are hopeful their discovery is valid. Dr. David Lafrenière, one of the co-discoverers, stated, “If we confirm that this object is indeed gravitationally tied to the star, it will be a major step forward.” [National Geographic]

He adds, "Of course it would be premature to say that the object is definitely orbiting this star, but the evidence is extremely compelling. This will be a very intensely studied object for the next few years!" [MSNBC: "Photo may reveal planet orbiting sunlike star"]