Scientific Projects

• The star formation at low metallicity: Dolidze 25

The content of metals (i.e. everything which is not hydrogen or helium in the warped astrophysical nomenclature) has changed during the evolution of the Universe: since stars burns in their core hydrogen and helium to produce more heavy elements, it has increased since the formation of the first stars. Besides, it also changes with the position within galaxies. One of the fundamental question is thus: does star and planet formation occurs differently in environments with different metal content?

It has always been difficult to answer this question since low-metallicity star-forming regions are typically very distant from us, mainly being hosted in the outer arms of our Galaxy or in outer galaxies. One exception to this is the young (4-6 Myrs) cluster Dolidze 25: at a distance of 4 kpc is the closest low metallicity (Z=0.17 Zsol) cluster to our Sun.

Motivated by the aim of studying the star formation in Dolidze 25 as template of low-metallicity star-forming environments, I have obtained a Chandra/ACIS-I observation 150 ksec long (Proposal n.: 200866) and an approved NASA grant of 50774 $.

The aim of the project is to identify stars associated to Dolidze 25 down to about 1 solar mass using the X-ray data jointly with existing optical and infrared data, both with and without disks, and verify whether the evolution of protoplanetary disks and the final product of star formation process have been affected by the low metallicity of the cluster.

Spitzer/IRAC image of Dolidze 25 in false colors, with marked the region observed with Chandra


Chandra/ACIS-I image of Dolidze25


Scientific products:

data analysis is still ongoing