GeminiFocus July 2014 | Page 5

Marie-Eve Naud and Étienne Artigau GU Psc b: An Unexpected Planetary-mass Companion Discovered with GMOS Capturing the faint light of an exoplanet near the blinding glow of its host star is a daunting task. It usually requires adaptive optics observations with specifically designed instruments and an arsenal of high-contrast imaging strategies. Our discovery of a giant exoplanet with the Gemini Multi-Object Spectrograph (GMOS) at Gemini South, however, shows that some planets might be much easier to find through “standard” imaging techniques. In 2008, the direct detection (by Gemini) of a planet around 1RXS 1609-2105 and four alien planets around the distant star HR 8799 (by Gemini and the W.M. Keck observatories) paved the road to a new era of direct imaging exoplanet discoveries. Since then, a few other planets have joined the still short list of new worlds imaged, including β Pictoris b, GJ 504 b, and HD 95086 b. There is high hope that the Gemini Planet Imager (GPI) and other new dedicated high-contrast imaging instruments will add many more objects to that list in the coming years. The amazing sophistication of these instruments, however, is testament to how difficult it remains to detect even the most massive exoplanets through direct imaging. A Planet Where There Shouldn’t Be Our team, which includes researchers from Université de Montréal and international collaborators, just announced the discovery of a new exoplanet, GU Psc b. This planet, with July 2014 GeminiFocus 3