Featured Research: Zooming In on Star Formation

The youngest stars are observed in dense clouds of gas and dust, but the details of how stars form from cloud material are still poorly understood, in part because the clouds obscure visible light. Several researchers (Dr. Lee Mundy, Dr. Marc Pound, Dr. Shih-Ping Lai, and graduate students Nicholas Chapman and Nikolaus Volgenau) in the Laboratory for Millimeter-wave Astronomy (LMA) are studying local star forming regions by observing radiation at wavelengths longer than visible light, which can more easily pass through the cloud material.

The recently-launched Space InfraRed Telescope Facility (SIRTF) will soon be used to map star forming regions in infrared light. They are also using observations of millimeter-wavelength emission made with the BIMA array in Hat Creek, California. Many simple molecules that are abundant in dense clouds, like carbon monoxide (CO), methanol (CH₃OH), and formaldehyde (H₂CO), emit radiation at millimeter wavelengths and allow the physical and kinematic properties of the cloud environment to be determined.

The image on the left (made by combining blue, green, and red light) shows the reflection nebula NGC1333 and the star formation region that surrounds it. The cloud that permeates the NGC1333 region is evident from the dark tendrils across the bright nebula in the upper left corner and also from several dark patches of starless sky. The BIMA map (center, heat colorscale) zooms in on several embedded protostars collectively called IRAS2. Notice that the bright star BD+30^o547, which appears in the center of the zoomed-in region (green square), doesn't appear in the BIMA map. This star is actually in the foreground, only about half the distance to the cloud. The BIMA map shows the emission from an isotope of the carbon monoxide molecule, revealing the shape of the clumps of gas that surround the protostars. The map on the right (rainbow colorscale) is also made with BIMA data; it shows the line-of-sight component of the velocity of the gas. The region where the IRAS2 stars are forming (contours) is moving at a different velocity (blue/green colors) from the rest of the surrounding gas (red/orange colors), suggesting that the stars may be forming where separate clumps of gas are interacting.

back to Astronomy

Past Features