The Extinction and Distance of the MBM Molecular Clouds at High Galactic Latitude

TL;DR

This study determines the distances and extinctions of 66 high-latitude molecular clouds in the MBM catalog using Gaia and star color excess data, revealing dust properties and disk structure.

Contribution

It provides new distance and extinction measurements for high-latitude molecular clouds and analyzes dust grain size variations and disk flaring.

Findings

Distances and extinctions for 66 molecular clouds are determined.

The color excess ratio indicates more small particles at lower extinction.

The dust disk scale height is about 100 pc, increasing towards the anticenter.

Abstract

Based on the accurate color excess $E_{\rm G_{BP},G_{RP}}$ of more than 4 million stars and $E_{\rm NUV,G_{BP}}$ of more than 1 million stars from \citet{2021ApJS..254...38S}, the distance and the extinction of the molecular clouds in the MBM catalog at $|b|>20^{\circ}$ are studied in combination with the distance measurement of \emph{Gaia}/EDR3. The distance as well as the color excess is determined for 66 molecular clouds. The color excess ratio $E_{\rm G_{BP},G_{RP}}/E_{\rm NUV,G_{BP}}$ is derived for 39 of them, which is obviously larger and implies more small particles at smaller extinction. In addition, the scale height of the dust disk is found to be about 100 pc and becomes large at the anticenter direction due to the disk flaring.