Like fresh fireworks launched against a background of dissipating smoke, blue and white stars shine brilliantly against a crimson background of glowing gas in this image of stellar nursery LH 95 from NASA’s Hubble Space Telescope.
LH 95 is a region in the Large Magellanic Cloud, a dwarf galaxy that orbits the Milky Way. Low-mass infant stars live alongside massive blue giant stars in what is known as a stellar association, one of many in the Large Magellanic Cloud.
The LH 95 region’s most massive stars, possessing at least three times the mass of the Sun and visible here as the largest and brightest blue stars, expel ultraviolet radiation and stellar winds that both heat and shape the surrounding hydrogen gas. Dark filaments stand out in sharp contrast against the glowing hydrogen where denser dust lanes resist erosion.
In this image, blue indicates the shorter wavelengths that are visible light, while red depicts the longer wavelengths of visible light, as well as some near-infrared light. Colors in Hubble images are chosen based on standard image processing techniques to best represent the wavelengths of light that pass through the filters used in the observation. The gas of the nebula glows crimson due to hydrogen-alpha emissions.
Hydrogen-alpha is an excellent indicator of star formation, allowing astronomers to identify very young stars embedded in this glowing gas. Researchers found developing stars still gathering material from the disks of gas and dust around them. In fact, LH 95 is home to an extraordinary 2,500 stars that have accumulated almost all of their critical mass but have not yet “turned on” by beginning fusion reactions. These stars, called “pre-main-sequence stars,” have formed from collapsing clouds of gas and are still contracting. They will soon begin burning hydrogen in their cores to become full stars.
By studying these forming stars, researchers confirmed that the stars’ accretion rate ― the rate at which they accumulate matter ― decreased with age, as expected. However, they also learned that accretion can persist for several million years, longer than sometimes assumed. This information helps refine our understanding of how young stars keep growing and how their disks evolve.
Researchers noted that distinct generations of stars in LH 95 exist side-by-side, indicating that rather than forming stars in a single event, the region produces multiple stellar generations over an extended period.
The most massive star in LH 95 (above center, slightly left) has about 60-70 times the mass of the Sun and is about a million years younger than the rest of stars in the system, which appear to be around 4 million years old. Massive stars like these burn through their fuel quickly and die in supernova explosions.
With its rich stellar population, LH 95 is valued by astronomers for providing a way to observe forming stars at relatively close range in an environment with less obscuring dust than similar regions of the Milky Way.
As one of NASA’s flagship observatories, Hubble has produced a wealth of scientific discoveries over more than 30 years in orbit. Its observations are expanded upon and enhanced by observations with other NASA missions, including the infrared-detecting Webb Space Telescope and the upcoming Nancy Grace Roman Space Telescope, which is scheduled to launch in late summer.
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Media Contact:
Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov
