L & M band infrared studies of V4332 Sagittarii - detection of the water-ice absorption band at 3.05 microns and the CO fundamental band in emission

摘要

L and M band observations of the nova-like variable V4332 Sgr are presented.Two significant results are obtained viz. the unusual detection of water ice at3.05 microns and the fundamental band of 12CO at 4.67 microns in emission. Theice feature is a first detection in a nova-like variable while the CO emissionis rarely seen in novae. These results, when considered together with otherexisting data, imply that V4332 Sgr could be a young object surrounded by acircumstellar disc containing gas, dust and ice. The reason for a nova-likeoutburst to occur in such a system is unclear. But since planets are believedto form in such disks, it appears plausible that the enigmatic outburst ofV4332 Sgr could be due to a planetary infall. We also give a more reliableestimate for an epoch of dust formation around V4332 Sgr which appears to havetaken place rather late in 1999 - nearly five years after its outburst.