DISCOVERY OF MOLECULAR HYDROGEN IN SN 1987A

Abstract

Both CO and SiO have been observed at early and late phases in SN 1987A. H 2 was predicted to form at roughly the same time as these molecules, but was not detected at early epochs. Here, we report the detection of NIR lines from H 2 at 2.12 and 2.40 μ m in VLT/SINFONI spectra obtained between days 6489 and 10,120. The emission is concentrated to the core of the SN in contrast to H α and approximately coincides with the [Si i ]/[Fe ii ] emission detected previously in the ejecta. Different excitation mechanisms and power sources of the emission are discussed. From the nearly constant H 2 luminosities, we favor excitation resulting from the 44 Ti decay.