Blue stars steal the show in NGC 2031

NASA’s Hubble House Telescope picture of the star-filled globular cluster NGC 2031 is furthering scientists’ understanding of “stellar contamination,” or probably a rejuvenated class of stars known as “blue stragglers.”

Positioned within the Giant Magellanic Cloud (LMC) within the constellation Mensa the Desk Mountain, NGC 2031, like all globulars, shows a spherical form attributable to long-term mutual gravitational interactions between many elderly stars. Astronomers usually have issue measuring the distances to the cluster’s stars as a result of the density of the LMC area it is positioned in ends in what is called stellar contamination — the place the atmospheres and floor options of the cluster’s tightly packed stars intrude with observations.

In response to a NASA release, contamination may clarify why NGC 2031 shows so many vibrant blue stars close to its core (pictured on the prime left nook of the picture above). These bluer stars are considerably out-of-place in a globular cluster as a result of they sometimes burn scorching and die younger, whereas most globulars are residence to a lot older crimson stars.

However one other attainable rationalization for the blue stars on this globular is that they’re a kind of star often known as a blue straggler. These second-chance stars are regarded as the results of two older crimson stars merging. The mixed mass of the ensuing star makes it burn extra intensely, giving it a younger look that appears misplaced in a globular cluster. Hubble beforehand discovered potential proof for such stars in a special cluster, 47 Tucanae.

Whereas NGC 2031 is comparatively cramped and laborious to review for a globular cluster, based mostly on the area’s 14 Cepheid variable stars — stars that brighten then dim in common durations — astronomers had been capable of pin down the clusters distance to about 150,000 light-years. The cluster is simply 140 million years outdated and holds some 3,000 instances the mass of the Solar.