Beating the blues – Hot companions of blue stragglers
Today’s paper searches for hot binary companions of blue straggler stars.
Today’s paper searches for hot binary companions of blue straggler stars.
Some stars in clusters have found the fountain of youth. Turns out, their secret is spreading: many more stars than we thought are in on it.
Recent surveys of the sky showed the presence of stars that seem to be too young for the population that they belong to. In today’s bite, we will see that cannibalism between two very close stars could be a viable way to produce these curious objects.
The authors identify two distinct sequences of blue straggler stars in the globular cluster NGC 392. They hypothesize that one branch is formed via stellar mergers and the other is binary stars undergoing mass transfer. This is the second globular cluster found to possess this double sequence.
Blue stragglers are stars within a globular cluster that lie along an extension of the main-sequence, above the turnoff point. As such they appear to be much younger than the rest of their stellar population. Current research suggests that they form by coalescence of mass-transfer between two companions in a binary system and the merger of two stars induced by stellar collision. By observing the population distributions of blue stragglers in globular clusters we can learn about the mechanisms through which they formed and the evolutionary dynamics of the cluster itself.