How to determine clouds mass which forms into a star?

Isolated molecular clouds can have a temperature as low as 15 K and a particle density as great as 1.4脳10^5 per cubic centimeter.



1. What is the minimum mass that a cloud with these properties needs in order to form a star?How to determine clouds mass which forms into a star?The well-known and heavily used method of gravitational perturbations of the nearby stars in their movements, is quite useful since a gaseous body, several light years across may be, but behaves as though its center is where all that mass is concentrated.

Spectroscopic studies give clues about abundance of the elements %26amp; molecules (you said 15掳K where compounds exist and that too in solid form). Radio (-Spectroscopic) studies at 21cm wave length is very valuable to map neutral Hydrogen molecules.

Your density of 1.4脳10^5 per cubic centimeter translates to a 'mole of Hydrogen' occupying a volume of 4.3 trillion cubic meters (cube of 16.23 km on a side). Not much and not much of mass too; but the density varies across the cloud with the central portion highly compressed. It implies a temperature profile of variation across the cloud. The tried %26amp; trusted Thermodynamics equations (starting with PV=RT) still work with far-reaching results.

What I said above is cursory but a picture of the gas cloud can be constructed from all these bits and pieces gleaned from various Astrophysical studies. This is the stuff of which 'Astronomical Reasearch' is made of.