Direct Imaging of Multiple Planets Orbiting the Star HR 8799

TL;DR

This paper reports the direct imaging of three exoplanets orbiting HR 8799, demonstrating the capability of high-contrast imaging to detect and analyze wide-orbit planets with detailed orbital and mass estimates.

Contribution

First direct imaging of multiple planets around HR 8799, showcasing the potential of high-contrast telescopic observations for exoplanet discovery and characterization.

Findings

Detected three planets with separations of 24, 38, and 68 AU.

Confirmed counter-clockwise orbital motion for all three planets.

Estimated planetary masses between 5 and 13 Jupiter masses.

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 towards imaging Earth-like planets. Imaging detections are challenging due to 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.