Gemini Observatory Image Shows Possible Extrasolar Planet

So, there I was on Friday night, playing with a computer game when I got a call from the Public Information Office at Gemini Observatory. I do some editing and writing for them from time to time, and since they’re six hours behind me (time-zone-wise) a late Friday call is not exactly a surprise. But, what Peter Michaud (their PIO) told me next was big news: that Gemini had likely bagged the first known image of a planet orbiting another star similar to the Sun. Not only that, but it is a HUGE planet (8 Jupiter masses) and orbits more than three hundred times the Earth-Sun distance from its own parent star.

This, as you might expect if you follow extrasolar planet searches, is big news. Nobody has directly imaged an actual planet around a normal star like the Sun before. Stars are too bright and planets are usually too small to be seen in the glare of the nearby star.  So far, planet discoveries have been made using several indirect methods, such as the Doppler detection technique (which measures the Doppler shift in starlight that occurs as a star and its planet(s) orbit around a common center of mass) about which you can read more here.

So, as you can imagine, an actual image of an extrasolar planet is pretty exciting; so much so that when the team of astronomers at the University of Toronto that did the work posted a pre-print paper about their finding, people took immediate notice. Gemini Observatory then worked up a press release (that a number of us then finessed over the weekend) and it came out early today. I expect this news will generate a lot of excitement and discussion in planetary-search circles.

The suspected star-planet combo (which lies about 500 light-years from Earth) was found as part of a survey of over 85 stars in the Upper Scorpius association, a group of young stars formed about 5 million years ago.

“This is the first time we have directly seen a planetary mass object in a likely orbit around a star like our Sun,” said David Lafrenière, lead author of a paper submitted to the Astrophysical Journal Letters and also posted online. “If we confirm that this object is indeed gravitationally tied to the star, it will be a major step forward.”

The near-infrared images and spectra of this suspected planetary object indicate that it is too cool to be a star or even a more massive brown dwarf, and that it is very young. Spectra indicate that it is the same distance from Earth as its star. It will probably take the better part of two years to absolutely confirm that this planet is definitely orbiting that star, but the science team making the discovery points to this data as very compelling evidence to prove that it is.

The team’s Gemini observations took advantage of adaptive optics technology to dramatically reduce distortions caused by turbulence in Earth’s atmosphere so they could make out the object, which appears to be orbiting its primary star at a distance of about 330 astronomical units.  To put this in comparison to our own solar system, Neptune orbits the Sun at about 40 AU, Pluto is at 39.4 AU.