High Resolution K-band Spectroscopy of MWC 480 and V1331 Cyg

TL;DR

This study uses high-resolution K-band spectroscopy to investigate the inner disk regions of two young stars, MWC 480 and V1331 Cyg, revealing strong water vapor emission in one and a featureless spectrum in the other, challenging previous interpretations.

Contribution

It provides detailed high-resolution spectra of MWC 480 and V1331 Cyg, offering new insights into their inner disk compositions and the origins of continuum excess emission.

Findings

V1331 Cyg shows strong CO and hot water vapor emission.

MWC 480 spectrum is mostly featureless, with no strong water emission detected.

The continuum excess in MWC 480 may have a different origin than hot water emission.

Abstract

We present high resolution (R=25,000-35,000) K-band spectroscopy of two young stars, MWC 480 and V1331 Cyg. Earlier spectrally dispersed (R=230) interferometric observations of MWC 480 indicated the presence of an excess continuum emission interior to the dust sublimation radius, with a spectral shape that was interpreted as evidence for hot water emission from the inner disk of MWC 480. Our spectrum of V1331 Cyg reveals strong emission from CO and hot water vapor, likely arising in a circumstellar disk. In comparison, our spectrum of MWC 480 appears mostly featureless. We discuss possible ways in which strong water emission from MWC 480 might go undetected in our data. If strong water emission is in fact absent from the inner disk, as our data suggest, the continuum excess interior to the dust sublimation radius that is detected in the interferometric data must have another origin. We discuss possible physical origins for the continuum excess.