In order to fully understand the gravitational collapse of molecular clouds, the star formation process, and the evolution of circumstellar disks, these phenomena must be studied in different Galactic environments with a range of stellar contents and positions in the Galaxy. The young massive association Cygnus OB2, in the Cygnus-X region, is a unique target to study how star formation and the evolution of circumstellar disks proceed in the presence of a large number of massive stars. We present a catalog obtained with recent optical observations in the r, i, z filters with OSIRIS, mounted on the 10.4 m Gran Telescopio CANARIAS telescope, which is the deepest optical catalog of Cyg OB2 to date. The catalog consists of 64,157 sources down to M = 0.15 M ☉ at the adopted distance and age of Cyg OB2. A total of 38,300 sources have good photometry in all three bands. We combined the optical catalog with existing X-ray data of this region, in order to define the cluster locus in the optical diagrams. The cluster locus in the r – i versus i – z diagram is compatible with an extinction of the optically selected cluster members in the 2.64 m < AV < 5.57 m range. We derive an extinction map of the region, finding a median value of AV = 4.33 m in the center of the association, decreasing toward the northwest. In the color-magnitude diagrams, the shape of the distribution of main-sequence stars is compatible with the presence of an obscuring cloud in the foreground ~850 ± 25 pc from the Sun.
Advertised on
References
2012 ApJS, 202, 19
It may interest you
-
It’s been decades since the need to study other stars to understand the past, present and future of the Sun was realized. One important aspect that has been investigated is the magnetic activity of stars for which we cannot fully grasp the mechanisms involved. Indeed, the origin of stellar magnetic cycles or the dependence of the magnetic activity on the stellar properties are not completely understood. This knowledge improves not only our understanding of the physics involved in stellar evolution but also affects the study of the Sun to better predict high-energy events and the betterAdvertised on
-
Ultra-diffuse galaxies, an extreme type of dwarf galaxy, have been the focus of extensive observational and theoretical studies over the past decade. With stellar masses comparable to dwarf galaxies (between 10 7 and 10 9 solar masses) but much larger in size (as defined by their effective radius), they exhibit an extremely low surface brightness. These galaxies display highly diverse properties: some have large dark matter halos, others lack them, and their number of globular clusters varies widely. Studies of their kinematics and stellar populations have shown that these extreme galaxiesAdvertised on
-
The solar corona—the outermost layer of the Sun’s atmosphere—is extremely hot and very low in density. One of the main challenges in solar physics is understanding why the corona reaches temperatures of over a million degrees. This heating is believed to be closely related to the Sun’s magnetic field. However, quantifying the coronal magnetic field is difficult because the light emitted by the corona is extremely faint, and its polarization signals, which encode the information on the magnetic field, are subtle. Thanks to recent advances in technology, telescopes like the Daniel K. InouyeAdvertised on