Stars thrive as vampires, sucking hydrogen from others

TORONTO - Like Hollywood villains, stars in distant galaxies too seem to bank on vampirism to thrive, new research says. The stars appear in two groups — those which suck fresh hydrogen from the bigger stars and others that rejuvenate from cosmic collisions.

Astronomers say there are age-defying stars that act as ‘vampires’ and suck fresh hydrogen from the bigger stars. There are some evergreen stars in Messier 30 - a cluster of hundreds of thousands of stars that formed 13 billion years ago - who defy age and always appear younger than the rest.

Called ‘blue stragglers’, these stars have been found by the Hubble Space Telescope. It has also found that there are two populations of these ‘blue stragglers’ or youthful stars.

Alison Sills of the department of physics & astronomy at McMaster University in Hamilton near Toronto said these so-called ‘blue stragglers’ appear to return to a hotter and brighter ‘youth’ from an ‘old age’, gaining a new lease on life in the process.

The new study shows that these ‘blue stragglers’ can also get rejuvenation from ‘cosmic facelift’ triggered by cosmic collisions.

In these cosmic collisions, the stars actually merge, mixing their nuclear fuel and

re-stoking the fires of nuclear fusion. Merged stars and binary systems would both be about twice the typical mass of individual stars in the cluster.

“The observations, which agree with our models, demonstrate that blue stragglers formed by collisions have slightly different properties from those formed by vampirism,” said Sills in a university statement Tuesday.

“This provides a direct demonstration that the two formation scenarios are valid and that they are both operating simultaneously in this cluster,” the Canadian scientist said.

The data from Hubble also showed that these ‘blue stragglers’ are much more concentrated towards the centre of the cluster than the other stars.

The increased density of stars at the centre increased the number of collisions among stars, thus leading to the formation of one of the families of ‘blue stragglers’.

It also perturbed the twin systems, encouraging ‘vampirism’ and formation of the other family of ‘blue stragglers’.

The study has been published in the latest issue of Nature.

The genre of vampire films, including the latest “Twilight series”, is famous in Hollywood.