The Shadow of Comet Hale–Bopp in Lyman-Alpha

  title={The Shadow of Comet Hale–Bopp in Lyman-Alpha},
  author={R. Lallement and J L Bertaux and K{\'a}roly Szeg{\"o} and Szilvia Nemeth},
  journal={Earth, Moon, and Planets},
For a few months around perihelion, thecentral part of the Hale–Bopp hydrogencloud has been optically thick to thesolar Lyα radiation, and hassignificantly reduced the solar flux availablefor the resonance glow of interstellarhydrogen beyond the comet. This shadowing effecton the interstellar gas is the first everobserved comet shadow. It is modeled andcompared with SWAN observations. Shadowmodelling will help to constrain the cometwater production and radiative transfer effectsin the… 

The Science of Sungrazers, Sunskirters, and Other Near-Sun Comets

This review addresses our current understanding of comets that venture close to the Sun, and are hence exposed to much more extreme conditions than comets that are typically studied from Earth. The



SOHO/SWAN Observations of the Structure and Evolution of the Hydrogen Lyman-α Coma of Comet Hale–Bopp (1995 O1)

Abstract The SWAN all-sky camera on the SOHO spacecraft observed the hydrogen Lyman-alpha coma of Comet Hale–Bopp (1995 O1) from January through May 1997. The observations covered heliocentric

First Results from SWAN Lyman α solar wind mapper on SOHO

After one year of almost flawless operation on board the SOHO spacecraft poised at L1 Lagrange point, we report the main features of SWAN observations. SWAN is mainly dedicated to the monitoring of