Star Formation


Star is considered to be formed by self gravitating collapse of the interstellar gas in the gas (molecular) cloud which is observed by molecular emission lines such as CO line. Molucular clouds observed in Taurus and Orion are typical examples. The dense core in the molecular cloud is called molecular cloud core. The molecular cloud cores in Taurus observed by C18O isotope molecules typically have radius=0.2 pc and number density of Hydrogen molecules=10000 particle/cc. Temperature is almost constant at T=10 K. Young Stellar Objects are often to be associated with the molecular cloud core. Let's follow the star formation from when the isotrope spherical molecular cloud starts to collapse and increases its central density by its self-gravity, through forming a high density molecular cloud core, to the on set of the young star formation.

Simulation Results


To show initial states, please place the mouse on figures.

The figure has loglismic axes and the center is enlarged. The flow toward the center is formed by the gravitational instability, the density at the center is increasing. At the last stage, the central density is 1000 times larger than initial value.

Basic Equations

Isothermal spherical Hydrodynamic equations with self-gravity.

Detailed Explanation

Please refer THIS document (PDF file in Japanese) for detailed explanation.


Ogino, S., Tomisaka, S., \& Nakamura, F. 1999, PASJ, 51, 637