title: Direct imaging of multiple planets orbiting the star HR 8799.
abstract: Direct imaging of exoplanetary systems is a powerful technique that can reveal Jupiter-like planets in wide orbits, can enable detailed characterization of planetary atmospheres, and is a key step toward imaging Earth-like planets. Imaging detections are challenging because of the combined effect of small angular separation and large luminosity contrast between a planet and its host star. High-contrast observations with the Keck and Gemini telescopes have revealed three planets orbiting the star HR 8799, with projected separations of 24, 38, and 68 astronomical units. Multi-epoch data show counter clockwise orbital motion for all three imaged planets. The low luminosity of the companions and the estimated age of the system imply planetary masses between 5 and 13 times that of Jupiter. This system resembles a scaled-up version of the outer portion of our solar system.
authors.affiliation: National Research Council Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7, Canada. christian.marois@nrc-cnrc.gc.ca
authors.forename: Christian
authors.initials: C
authors.lastname: Marois
authors.forename: Bruce
authors.initials: B
authors.lastname: Macintosh
authors.forename: Travis
authors.initials: T
authors.lastname: Barman
authors.forename: B
authors.initials: B
authors.lastname: Zuckerman
authors.forename: Inseok
authors.initials: I
authors.lastname: Song
authors.forename: Jennifer
authors.initials: J
authors.lastname: Patience
authors.forename: David
authors.initials: D
authors.lastname: Lafrenière
authors.forename: René
authors.initials: R
authors.lastname: Doyon