Initial Mass Function

Initial Mass Function

The elliptical galaxy NGC 1600 is 200 million light-years distant from us. In the picture of the Hubble telescope, it is located in the center. After a long study, researchers believe that the relative populations of stars of different masses in clusters are affected by the velocity distribution.

Gradually, gas and dust in large-scale molecular clouds merge due to the influence of gravity and form stars. But the details of the process are not entirely clear. For example, the most important factor is the stellar mass, which will also affect the evolution of an object. But scientists do not understand what exactly determines the exact mass. The initial mass function (PFM) describes the distribution of stellar masses in a large cluster and now it is based on an average review of the stars of the Milky Way.

The observed PFM has a relatively small number of massive stars, but many sun-like ones. There are even more low-mass stars, but it is difficult to create accurate statistics because they are weak and not always displayed in reviews. Researchers are also considering the theoretical basis for the PFM in order to transfer the picture of our galaxy to the whole space. For example, the relative number of elements (metallicity) in a collapsing cloud was suggested as one of the ways to change the PFM. For a long time everyone believed in the versatility of the PFM, but only recently was it possible to test this assumption thanks to sensitive instruments. Stars of different masses are endowed with atmospheres demonstrating various spectral features. Therefore, the spectroscopy of a distant cluster cannot resolve individual objects, but is able to derive the proportions of stars of different masses.

The Keck Observatory telescope and its spectrometer were used for analysis. Contrary to expectations, the researchers say that metallicity is not the main culprit for change. But now in the first place becomes the speed indicator of the material in star clusters. This suggests that it will be necessary to change the theoretical basis for studying PFM.

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