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California molecular cloud
The California Molecular Cloud presents a unique opportunity to study star formation at early stages due to its low star formation activity. The high-extinction parts of the cloud, where star formation is typically observed, contain only a fraction of the mass found in comparable regions such as the Orion A Molecular Cloud. The number of young stellar objects (YSOs), an indicator of star formation activity, is significantly lower in the California MC compared to the Orion A MC. The limited star formation efficiency and the presence of only one B-type main-sequence star in the southeastern part of the California MC make it an ideal candidate for studying early-stage star formation processes.

The California MC's distinct X-shaped region is particularly noteworthy. It features two low-density filaments intersecting at a dense hub region, extending southeast and southwest with an intersection angle of approximately 60 degrees in the plane of the sky. Two star-forming filaments stood out X-shaped region because they had chains of closely spaced dense cores. These filaments are dynamically active and not in a static state. A filament is drawing in gas from its surrounding cloud. Another one had two developing protostars with outflows, indicating a more advanced stage of growth. Surprisingly, the spacing between the cores in these filaments was smaller than expected. It is unlikely that this difference is due to the way we observe them. Instead, the continuous gas accumulation onto the filaments and their curved shapes may be responsible for the observed core spacing.