Scientists had previously suspected that there was a large planet orbiting the star because of "wobbles" in its movement. But now pictures taken by an instrument installed last year on the orbiting telescope show a faint point of light near the small star. Members of the team which made the latest discovery, led by Al Schultz of the Space Telescope Science Institute in Baltimore, are keeping an open mind. They have ruled out other explanations such as instrumental effects, or a star seen in the background.
But even if it is a planet, it is unlikely to harbour life. Proxima Centauri is a tiny, dim star, with a mass only one-tenth that of our Sun, a comparatively low temperature and a luminosity one-thousandth that of ours. Some scientists have suggested that it might be a brown dwarf - a failed star which is too small to shine. Dr Alan Penny, of the Rutherford Appleton Laboratory in Didcot, Oxfordshire, said: "I think it's more likely to be a brown dwarf, but we need more observations ... " -- Charles Arthur, Science EditorReuse content