White Dwarf Stars in M4

A view of globular cluster M4 (fourth object in the Messier catalog of star clusters and nebulae). The nearest globular cluster to Earth (7, 000 light-years away), and containing more than 100, 000 stars, M4 was the target of a Hubble Space Telescope search for white dwarf stars.

The box (right of center) shows the small area that Hubble telescope probed.

Credit: M. Bolte (University of California, Santa Cruz) and Kitt Peak National Observatory 0.9-meter telescope

A Hubble Space Telescope colour image of a small portion of the cluster only 0.63 light-years across reveals eight white dwarf stars among the cluster's much brighter population of yellow sun-like stars and cooler red dwarf stars.

Hubble reveals a total of 75 white dwarfs in one small area within M4, out of the total of about 40, 000 white dwarfs that the cluster is predicted to contain.

Credit: Harvey Richer (University of British Columbia, Vancouver, Canada) and NASA