The search for planets other than those in our own solar system (exoplanets) has been going on since the early 1990’s. Most of the searches and discovery of planets have been done by indirect means, for example, catching the shadow of a planet as it transits the local star, or detecting the perturbation in the orbit of a star (indicating the presence of a planet). Although more than 400 planets have been discovered, few of them have been observed directly, that is, not captured in a direct image. That’s changing, however, with the advent of a new generation of telescopes specifically engineered for hunting exoplanets.
One of the most recent ‘scopes is among the world’s largest, the Subaru 8.2 meter telescope located on Mauna Kea in the Hawaiian Islands. Not only is it ‘big’ (meaning it can detect more distant objects) but it is equipped with a special filtering system, called a High Contrast Coronagraphic Imager with Adaptive Optics, that can remove the light emitted by a star in order to reveal the relatively dim planets in orbit around it.
An international team of scientists…has made the first direct observation of a planet-like object orbiting a star similar to the sun.
The finding marks the first discovery made with the world’s newest planet-hunting instrument on the Hawaii-based Subaru Telescope and is the first fruit of a novel research collaboration announced by [Princeton University] in January.
The object, known as GJ 758 B, could be either a large planet or a “failed star,” also known as a brown dwarf. The faint companion to the sun-like star GJ 758 is estimated to be 10 to 40 times as massive as Jupiter and is a “near neighbor” in our Milky Way galaxy, hovering a mere 300 trillion miles from Earth.
The discovery of a new planet (actually, a second planet may also have been discovered in the same system but it is not yet verified), is no longer big news; but in this case there’s a triple-banger for the telescope buck:
1. “It’s a groundbreaking find because one of the current goals of astronomy is to directly detect planet-like objects around stars like our sun.”
2. “It is also an important verification that the system — the telescope and its instruments — is working well.”
3. The fact that such a large planet-like object appears to orbit at this location defies traditional thinking on planet formation. It is thought most larger planets are formed either closer to or farther from stars, but not in the location where GJ 758 is now. Discoveries such as this one could help theorists refine their ideas.