Molecular cores of the high-latitude cloud MBM 40

Abstract

Towards the high-latitude cloud MBM 40, we identify 3 dense molecular cores of M∼0.2–0.5 M ⊙, and sizes of ∼0.2 pc in diameter embedded in the H I cloud of ∼8 M ⊙ which is observed to be extended along the northeast–southwest direction. The molecular cloud is located almost perpendicularly to the H I emission. We confirm the previous result of Magnani et al. that MBM 40 is not a site for new star formations. We found a very poor correlation between the H I and the IRAS 100 μm emissions, but the CO (1–0) and 100 μm emissions show a better correlation of W CO/ I 100=1±0.2 K km s −1 (MJy sr −1) −1. This ratio is larger by a factor of ≥5 than in dense dark clouds, which may indicate that the CO is less depleted in MBM 40 than in dense dark clouds.