W3 is an enormous stellar nursery about 6,200 light-years away in the Perseus Arm, one of the Milky Way galaxy's main spiral arms, which hosts both low- and high-mass star formation. In this image from the Herschel space observatory, the low-mass forming stars are seen as tiny yellow dots embedded in cool red filaments, while the highest-mass stars -- with greater than eight times the mass of our sun -- emit intense radiation, heating up the gas and dust around them and appearing here in blue.
Herschel is a European Space Agency cornerstone mission, with science instruments provided by consortia of European institutes and with important participation by NASA. NASA's Herschel Project Office is based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the United States astronomical community. Caltech manages JPL for NASA.