First L-band Interferometric Observations of a Young Stellar Object: Probing the Circumstellar Environment of MWC 419

TL;DR

This study uses L-band interferometry to spatially resolve the circumstellar disk of the young star MWC 419, revealing a temperature gradient and inner gas emission regions, advancing understanding of stellar formation environments.

Contribution

First L-band interferometric observations of MWC 419 providing detailed disk size and temperature structure analysis with new interferometric techniques.

Findings

Disk size increases linearly with wavelength, indicating an extended disk with a temperature gradient.

A power-law temperature gradient model fits both interferometric and spectral data.

Inner hydrogen gas emission is located within the dust disk region.

Abstract

We present spatially-resolved K- and L-band spectra (at spectral resolution R = 230 and R = 60, respectively) of MWC 419, a Herbig Ae/Be star. The data were obtained simultaneously with a new configuration of the 85-m baseline Keck Interferometer. Our observations are sensitive to the radial distribution of temperature in the inner region of the disk of MWC 419. We fit the visibility data with both simple geometric and more physical disk models. The geometric models (uniform disk and Gaussian) show that the apparent size increases linearly with wavelength in the 2-4 microns wavelength region, suggesting that the disk is extended with a temperature gradient. A model having a power-law temperature gradient with radius simultaneously fits our interferometric measurements and the spectral energy distribution data from the literature. The slope of the power-law is close to that expected from an optically thick disk. Our spectrally dispersed interferometric measurements include the Br gamma emission line. The measured disk size at and around Br gamma suggests that emitting hydrogen gas is located inside (or within the inner regions) of the dust disk.