Infrared sounding of Comet Halley from Vega 1

The IKS instrument carried by the Vega 1 spacecraft performed infrared sounding of the inner coma and nuclear region of comet Halley. An emissive centre, a few kilometres in size, was detected with a temperature significantly in excess of 300 K. In the surrounding central coma, hydrocarbon species or other carbonaceous material seem to be present. The fluorescence signatures of H2O and CO2 were identified.