In a new image from the James Webb Space Telescope (JWST), transient configurations of dust and gas in a nearby galaxy glow.

NGC 6822, or Barnard's Galaxy, is the closest galaxy to the Milky Way at 1.6 million light-years away and is not one of its satellites. It is a small dwarf galaxy only 7,000 light years across and is very low in heavy elements, but most of its stars were born within the last 5 billion years. This apparent property mismatch makes the Barnard Galaxy the perfect laboratory for studying the evolution of galaxies in the early Universe, when there were not yet many metals.

This is because all the elements in the Universe heavier than hydrogen and helium were formed by stars. These giant fireballs split atoms in their cores to form heavier elements, up to iron, and when they explode or collide at the end of their lives, the extreme violence again produces heavier elements.

Barnard's galaxy has spent most of its life in relative isolation, not interacting with any other object. This may be one of the reasons why it has such a low metallicity: it has experienced relatively few gravitational disturbances that could have compressed its dust and gas to trigger star formation. However, around 3-4 billion years ago, scientists think it got close enough to the Milky Way that the gravity of our large galaxy stirred things up.

Apparently, this is great news for us. We have a nearby object with low metallicity that forms stars, and this gives us a window into what galaxies in the early Universe might have looked like.

And JWST is the perfect observatory for this task. The mid-infrared instrument MIRI can see the subtleties of infrared light emitted by gas, and the near-infrared instrument NIRCam renders dust and gas invisible to see the stars they hide.

The newly released image from JWST combines images from both instruments. The greenish-yellowish swirls are gas and dust; the bright red and represent regions of star formation; the orange blobs are more distant galaxies, and the dense field of twinkling stars permeates them all.

Studies of this fascinating galaxy are still ongoing, but we hope the results will help astronomers understand a little more about how it all began in the Universe.

 

Source: https://www.sciencealert.com/