Haze in Pluto's atmosphere: Results from SOFIA and ground-based observations of the 2015 June 29 Pluto occultation

On UT 29 June 2015, the occultation by Pluto of a bright star (r' = 11.9) was observed from the Stratospheric Observatory for Infrared Astronomy (SOFIA) and several ground-based stations in New Zealand and Australia. Pre-event astrometry allowed for an in-flight update to the SOFIA team with the result that SOFIA was deep within the central flash zone (similar to 22 km from center). Analysis of the combined data leads to the result that Pluto's middle atmosphere is essentially unchanged from 2011 and 2013 (Person et al. 2013; Bosh et al. 2015); there has been no significant expansion or contraction of the atmosphere. Additionally, our multi-wavelength observations allow us to conclude that a haze component in the atmosphere is required to reproduce the light curves obtained. This haze scenario has implications for understanding the photochemistry of Pluto's atmosphere.

Automated summary

On 29 June 2015, the occultation by Pluto of a bright star was observed from multiple ground-based stations and the Stratospheric Observatory for Infrared Astronomy (SOFIA). Analysis of the data shows that there has been no significant expansion or contraction of Pluto's middle atmosphere, and a haze component is required to reproduce the observed light curves, affecting the understanding of the atmosphere's photochemistry.