NASA’s Hubble Spies Superbubble Scene

 

This Hubble Space Telescope image features the picturesque nebula LHA 120-N44, or N44.

NASA, ESA/Hubble, D. Gouliermis

This NASA/ESA Hubble Space Telescope image features a sprawling cosmic vista in the Large Magellanic Cloud, or LMC, the largest of the small galaxies that orbit our Milky Way galaxy. At just 160,000 light-years away, the LMC offers a close look at highly active star birth sites like the one in this image. This photogenic nebula, named LHA 120-N44, or N44, is in the constellation Dorado.

N44 is dominated by two features: a vast central void and a shell of dense, dusty gas. The central void is a ‘superbubble’ spanning roughly 210 by 140 light-years across. The glittering stars at the center of the void are responsible for its creation; through their powerful stellar winds and explosive supernovae, these stars expelled much of the gas from which they were born.

When the stars of N44’s central star cluster swept away this gas, the expelled gas compressed and formed a shell around the superbubble. New stars are forming in this compressed gas shell, making N44 an interesting target for astronomers who are using the nebula to study how stars form in this environment. Their goal is to understand how long it takes from the collapse of cold gas clouds into dense knots to the moment nuclear fusion ignites in the heart of a newborn star.

The data in this image is from an observing program (#14689; PI: Gouliermis) that used Hubble to survey N44 and take a census of its stars, cataloging nearly half a million stars within the cluster as well as interlopers drifting in front of it. Of the stars surveyed, nearly 30,000 are what astronomers call pre-main-sequence stars, which have yet to begin fusing hydrogen into helium in their cores. Astronomers discovered this treasure trove of baby stars thanks to the high sensitivity and fine spatial resolution of Hubble’s instruments that can pick out faint objects in crowded clusters.

The gas shell surrounding the superbubble is energized by ultraviolet radiation from massive stars, causing it to glow and highlighting several distinct features. Each feature within the broader N44 star-forming complex was cataloged by astronomer Karl Henize in the 1950s. One feature is a smaller bubble, cataloged as N44F, that is located near the upper-right corner of this image. N44F is an interstellar bubble blown by the intense stellar winds of a single hot and massive star. As this previously released Hubble closeup shows, the star’s furious winds and radiation have sculpted the surrounding bubble and created pillars of dusty gas.

Hubble's sensitive observations of the lowest-mass stars in this region open a new window onto star formation in regions that, like the LMC or the galaxies in the early universe, are poor in elements heavier than helium.

Text Credit: ESA/Hubble 

Source: NASA's Hubble Spies Superbubble Scene - NASA Science