Institute of Astronomy

Far Infrared and Sub-millimeter Imaging of HR 8799

SpeakerTalk DateTalk Series
Mark Booth28 July 2014Across HR 2014 Posters


HR 8799 is well known for being the only star to host multiple planets discovered through direct imaging. HR 8799 also hosts a debris disc first discovered by IRAS. This disc was one of the few resolved by Spitzer showing that dust is present out to a few thousand AU. The Spitzer data also showed that there must be multiple components to the dust both inside and outside the orbits of the planets. Naturally, this system has been a prime target for observations from various telescopes in recent years. I will focus on the results of imaging with Herschel, ALMA cycle 0 and JCMT/SCUBA-2. The disc is found to be resolved at 70, 100, 160, 250 and 850 µm. The resolution of the Herschel data has allowed us to determine the inclination of the disc for the first time, showing it to be coplanar with the planets and star. Both Herschel and ALMA observations do not detect any clumpiness that might be expected due to interactions between the planets and the disc, implying that the eccentricity of the outermost planet is <0.1. Combined analysis of the spectral energy distribution and the resolved images presents new questions since the dust is seen to be distributed over a wide range of radii and yet only a narrow range of temperatures is seen.