The Hydrogen Coma of the Comet 67P/C-G (image) National Institutes of Natural Sciences Share Print E-Mail Caption Processed and cropped hydrogen-Lyα image of the comet 67P/C-G in Rayleigh units (upper panel) taken by the LAICA telescope on Sept. 13, 2015, UT, and the hydrogen coma appearance predicted by a two-dimensional axi-symmetric model of the atomic hydrogen coma (lower panel). The yellow dotted arrow in the lower panel indicates the direction to the sun at the time of observation. Credit NAOJ Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.