Icarus (MACS J1149+2223 Lensed Star 1)

The Farthest Star Ever Seen

Icarus, whose official name is MACS J1149+2223 Lensed Star 1, is the farthest individual star ever seen. It is only visible because it is being magnified by the gravity of a massive galaxy cluster, located about 5 billion light-years from Earth. Called MACS J1149+2223, this cluster, shown at left, sits between the Earth and the galaxy that contains the distant star. The team had been using Hubble to monitor a supernova in the far-off spiral galaxy when, in 2016, they spotted a point of light near the supernova that began to brighten. Even though the object subsequently became three times brighter in one month, the colors of the light coming from the object did not change. Analysis of these colors showed it was a blue supergiant star in the background galaxy whose magnification grew for several weeks due to an intervening object, probably a star, in the galaxy cluster. The panels at the right show the view in 2011, without Icarus visible, compared with the star’s brightening in 2016.

About the colours

These images are composites of separate exposures acquired by the ACS and WFC3 instruments on the Hubble Space Telescope. Several filters were used to sample broad wavelength ranges. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are: Blue: F606W+F814W Green: F105W+F125W Red: F140W+F160W

About the data

The HST observations include those from programs 12065 (M. Postman), 13459 (T. Treu), 13504 (J. Lotz), 13790 and 14208 (S. Rodney), and 14041 , 14199 , 14528 , 14872 , and 14922 (P. Kelly).