Wednesday, August 4, 2021

DOUBLE CLUSTER NGC 1850: SECOND BRIGHTEST STAR CLUSTER IN THE GREAT CLOUD OF MAGALHÃES

The NGC 1850 double cluster, found in one of our neighboring galaxies, the Large Magellanic Cloud, is an eye-catching object.  It is a young, "globular-like" star cluster - a type of object unknown in our own galaxy, the Milky Way.

 In addition, NGC 1850 is surrounded by a filigree pattern of diffuse gas, which scientists believe was created by the explosion of massive stars.

 NGC 1850, photographed here with NASA's Hubble Space Telescope, is an unusual double cluster that sits on the bar of the Large Magellanic Cloud, a satellite galaxy of our own Milky Way.  After the 30 Doradus complex, NGC 1850 is the brightest star cluster in the Large Magellanic Cloud.  It is representative of a special class of objects - young globe-like star clusters - that have no counterparts in our galaxy.  The two components of the cluster are relatively young and consist of a globular-shaped main cluster in the center and an even younger and smaller cluster, seen below and to the right, composed of extremely hot blue stars and fainter red Ts.  -Tauri stars.  The main cluster is about 50 million years old;  the smallest cluster is only 4 million years old.

 One of Hubble's main contributions to the study of NGC 1850 lies in the investigation of star formation at both ends of the stellar mass scale - the low-mass T-Tauri stars and the high-mass OB stars.

 The T-Tauri stars are young stars of the solar class that are still forming, so young that they may not have started to convert hydrogen into helium, which is how our Sun produces its energy.  Instead, they radiate energy released by their own gravitational contraction.  By investigating these stars, astronomers learn about the birth and life of low-mass stars.  T-Tauri stars tend to occur in crowded environments, but are themselves weak, making them difficult to distinguish with ground-based telescopes.  However, Hubble's fine angular resolution can identify these stars, even in galaxies other than our own.

 Hubble also has advantages when studying very massive stars.  These stars emit large amounts of energetic ultraviolet radiation, which is absorbed by the Earth's atmosphere.  From its position above the atmosphere, Hubble can detect ultraviolet light from these massive stars.  Hubble data can then be analyzed and used to characterize the properties of stars.

 This Hubble image is a good example of the interaction between gas, dust and stars.  Millions of years ago, massive stars in the main cluster exploded as supernovae, forming the spectacular filigree pattern of diffuse gas visible in the image.  The birth of new stars is believed to be triggered by the huge forces on the shock fronts where supernova explosion waves hit and compress the gas.  The cloudy gas is part of the N103 superbubble and looks like the well-known Cygnus circuit remnant from the supernova in our Milky Way.

 CREDITS:

 NASA, ESA, Hubble .

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