The Massive Starforming Region NGC 7538
Massive stars (greater than about 8 times the Sun’s mass) form and reach their final masses through a process that is (1) different, in its details, from the way low-mass stars form, and (2) those detailed differences are not very well understood. Like their low-mass counterparts, massive stars tend to form in large associations of dozens to hundreds, like the complex of forming stars called NGC 7538 (above). Still densely shrouded in dust, newborn high-mass stars here are turning on and flooding the space around them with intense ultraviolet photons, lighting up the gas and dust from which they formed. Their brief lives mean that most will die where they were born and lived, some tens of millions of years from now.
This color composite image is made from near-infrared data from the Infrared Array Camera (IRAC) aboard the Spitzer Space Telescope at wavelengths of 3.6 and 4.5 microns. The data were obtained from the public Spitzer archive.
This infrared image from NASA’s Spitzer Space Telescope shows the nebula nicknamed “the Dragonfish.” This turbulent region, jam-packed with stars, is home to some of the most luminous massive stars in our Milky Way galaxy. It is located approximately 30,000 light-years away in the Crux constellation.
The massive stars have blown a bubble in the gas and dust, carving out a shell of more than 100 light-years across (seen in lower, central part of image). This shell forms the “toothy mouth” of the Dragonfish, and the two bright spots make it up its beady eyes.
The infrared light in this region is coming from the gas and dust that are being heated up by the unseen central cluster of massive stars. The bright spots along the shell, including the “eyes,” are possible smaller regions of newly formed stars, triggered by the compression of the gas and dust by winds from the central, massive stars.
Infrared light in this image was captured by the infrared array camera on Spitzer, at wavelengths of 3.6 microns (blue); 4.5 microns (green); and 8.0 microns (red). The data were captured before Spitzer ran out of its liquid coolant in 2009, and began its “warm” mission.
Newborn stars, hidden behind thick dust, are revealed in this image of a section of the Christmas Tree Cluster from NASA’s Spitzer Space Telescope, created in joint effort between Spitzer’s Infrared Array Camera (IRAC) and Multiband Imaging Photometer (MIPS) instruments.
The newly revealed infant stars appear as pink and red specks toward the center of the combined IRAC-MIPS image (left panel). The stars appear to have formed in regularly spaced intervals along linear structures in a configuration that resembles the spokes of a wheel or the pattern of a snowflake. Hence, astronomers have nicknamed this the “Snowflake Cluster.”
Two extremely bright stars illuminate a greenish mist in this and other images from the new “GLIMPSE360” survey from NASA’s Spitzer Space Telescope. This fog is comprised of hydrogen and carbon compounds called polycyclic aromatic hydrocarbons (PAHs), which are found right here on Earth in sooty vehicle exhaust and on charred grills. In space, PAHs form in the dark clouds that give rise to stars. These molecules provide astronomers a way to visualize the peripheries of gas clouds and study their structures in great detail. They are not actually “green;” but are color coded in these images to let scientists see their glow in infrared.