NASA's Hubble Finds Rare Blue Straggler Stars in the Milky Way's Hub

Peering deep into the star-filled, ancient hub of our Milky Way (left), NASA's Hubble Space Telescope has found a rare class of oddball stars called blue stragglers. This is the first time such objects have been detected within our galaxy's bulge. Blue stragglers are so named because they seem to be lagging behind in their rate of aging compared with nearby older stars.

The discovery is a spin-off from a seven-day-long survey conducted in 2006 called the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS). Hubble peered at and obtained variability information for 180,000 stars in the crowded central bulge of our galaxy, 26,000 light-years away.

http://hubblesite.org/news_release/news/2011-16

On Friday, December 8, 2017 at 2:15:53 PM UTC-8, wrote:
Peering deep into the star-filled, ancient hub of our Milky Way (left), NASA's Hubble Space Telescope has found a rare class of oddball stars called blue stragglers. This is the first time such objects have been detected within our galaxy's bulge. Blue stragglers are so named because they seem to be lagging behind in their rate of aging compared with nearby older stars.

The discovery is a spin-off from a seven-day-long survey conducted in 2006 called the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS).. Hubble peered at and obtained variability information for 180,000 stars in the crowded central bulge of our galaxy, 26,000 light-years away.

http://hubblesite.org/news_release/news/2011-16

That is an old article, from 2011, and the thinking concerning Blue Stragglers has been modified over the last 6 years, see this...

https://en.wikipedia.org/wiki/Blue_straggler

.... where we read...

"The two most viable explanations put forth for the existence of blue stragglers both involve interactions between cluster members. One explanation is that they are current or former binary stars that are in the process of merging or have already done so. The merger of two stars would create a single more massive star, potentially with a mass larger than that of stars at the main-sequence turn-off point. While a star born with a mass larger than that of stars at the turn-off point would have already evolved off of the main sequence, a more massive star which formed via merger would not have evolved as quickly. There is evidence in favor of this view, notably that blue stragglers appear to be much more common in dense regions of clusters, especially in the cores of globular clusters. Since there are more stars per unit volume, collisions and close encounters are far more likely in clusters than among field stars and calculations of the expected number of collisions are consistent with the observed number of blue stragglers."

Fascinating stuff, isn't it?