Protostar in Dark Cloud SDC 335.579-0.292

Observations of the dark cloud SDC 335.579-0.292 using the Atacama Large Millimeter/submillimeter array (ALMA) have given astronomers the best view yet of a monster star in the process of forming. A stellar womb with over 500 times the mass than the Sun has been found and appears as the yellow blob near the center of this picture. This is the largest ever seen in the Milky Way — and it is still growing. The embryonic star within is hungrily feeding on the material that is racing inwards. It is expected to give birth to a very brilliant star with up to 100 times the mass of the Sun.

This image combines data from ALMA and NASA’s Spitzer Space Telescope.

Image credit: ALMA (ESO/NRAJ/NRAO)/NASA/Spitzer/JPL-Caltech/GLIMPSE

Note: For more information, see ALMA Prenatal Scan Reveals Embryonic Monster Star.

Infrared Dark Clouds in the Milky Way

Typically if an astronomer wants to see into or through a thick dark cloud in space, they will use an infrared-sensing telescope. However, in this infrared image from NASA's Wide-field Infrared Survey Explorer, or WISE, there are some clouds that are so cool and thick that even infrared light coming from within or the background can't penetrate them. The black areas in this image -- called infrared dark clouds -- are exceptionally cold, dense cloud cores seen in silhouette against the bright diffuse infrared glow of the plane of the Milky Way galaxy. The clouds are a great example of why it is so useful for astronomers to be able to observe in many different wavelengths of light.

If you were to look at this same region of the sky through a backyard telescope, you would see a sea of stars packed together, similar to the thousands of blue stars seen here. You might also notice small patches of darkness that appear to block out the stars behind them. But what you wouldn't see are these beautiful clouds colored green, yellow and red in this image from WISE. Those are only seen in infrared light. In fact, the places where you see dark patches with your eyes are often the places where WISE sees bright clouds with its infrared "eyes." This is because those clouds are dense enough to block visible light, but not dense enough to block longer wavelengths of infrared light that WISE detects. In addition, they are too cool to shine in visible light but still warm enough to glow brightly in infrared light.

However, the darkest areas here are places where the cloud is extremely compact and chilly, so much so that it is opaque even in the infrared wavelengths that WISE sees. To see them glow, one would need to look in even longer wavelengths, for example those detected by the European Space Agency's Herschel mission, which has important NASA contributions

These dark clouds are so dense that if you were located in the middle of one of them, you wouldn't be able to see anything -- no stars, no galaxies, only darkness. This dense material will eventually result in the formation of new stars and planets.

This image was made from observations by all four infrared detectors aboard WISE. Blue and cyan (blue-green) represent infrared light at wavelengths of 3.4 and 4.6 microns, which is primarily light from stars. Green and red represent light at 12 and 22 microns, which is primarily light from warm dust.

Photo credit: NASA/JPL-Caltech/UCLA