Program: GN-2021A-Q-401

We propose to obtain a 1-2.5um spectrum of the red hypergiant variable VY CMa, one of the most luminous stars in the Galaxy, suspected of having the largest diameter of any star currently known, and embedded in a remarkable extended reflection nebula. Despite its fame, its brightness, and the existence of a vast amount of spectral data at both shorter (optical) and longer (mid-far IR and mm/radio) wavelengths, surprisingly there is no published near-IR spectrum of VY CMa taken in the last five decades. The near-IR spectra that do exist were obtained in 1969, when IR astronomy was in its infancy, they are low resolution, low S/N and only cover part of the 1-2.5um interval. This proposed higher resolution and much higher S/N 1-2.5um spectrum will not only fully bridge the spectral gap between the optical and the mid-IR, but will also provide detailed information addressing a number of issues. The unusual optical and mm spectra of VY CMa, which show line emission from a number of molecular species, suggests that a high S/N 1-2.5um spectrum will reveal a wealth of molecular features including those of some species that are not detected at optical or mm wavelengths. The new spectrum also will allow the determination of the photospheric 12C/13C isotopic ratio, a key constraint for the evolutionary state of the star. The spectrum may also contain signatures of newly formed, very hot dust at ~ 1700K that would peak in the H band, arising from the first dust condensates such as alumina produced during recent high mass loss events. All or any of the above will lead to an improved understanding of this unique star and its ejecta.