Westerlund 2: Detail 4

The red dots scattered throughout the landscape around Westerlund 2 are a rich population of newly forming stars still wrapped in their gas-and-dust cocoons. These tiny, faint stars are between 1 million and 2 million years old and have not yet ignited the hydrogen in their cores. Hubble's near-infrared vision allows astronomers to identify these fledgling stars.

About the colours

These images are composites of separate exposures acquired by the ACS and the WFC3 instruments on the Hubble Space Telescope. Several filters were used to sample broad and narrow 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: F555W (V) Green: F555W (V) and F814W (I) Red: F814W (I)

About the data

Data of Westerlund 2 were obtained from the HST proposals 14038 : A. Nota (ESA/STScI), E. Sabbi and C. Christian (STScI), E. Grebel and P. Zeidler (Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg), M. Tosi (INAF, Osservatorio Astronomico di Bologna), A. Bonanos (National Observatory of Athens, Astronomical Institute), and S. de Mink (University of Amsterdam); and 14039 : Z. Levay, M. Mutchler, J. Mack, L. Frattare, S. Meyett, M. Livio, and C. Christian (STScI/AURA), K. Noll (NASA/GSFC), A. Nota (STScI/ESA), and E. Sabbi (STScI).