Credit: NASA/JPL-Caltech/J. Rho (SSC/Caltech)

Stellar 'Incubators' Seen Cooking up Stars

This image composite compares visible-light and infrared views from NASA's Spitzer Space Telescope of the glowing Trifid Nebula, a giant star-forming cloud of gas and dust located 5,400 light-years away in the constellation Sagittarius.

Visible-light images of the Trifid taken with NASA's Hubble Space Telescope, Baltimore, Md. (inside left) and the National Optical Astronomy Observatory, Tucson, Ariz., (outside left) show a murky cloud lined with dark trails of dust. Data of this same region from the Institute for Radioastronomy millimeter telescope in Spain revealed four dense knots, or cores, of dust (outlined by yellow circles), which are "incubators" for embryonic stars. Astronomers thought these cores were not yet ripe for stars, until Spitzer spotted the warmth of rapidly growing massive embryos tucked inside.

These embryos are indicated with arrows in the false-color Spitzer picture (right), taken by the telescope's infrared array camera. The same embryos cannot be seen in the visible-light pictures (left). Spitzer found clusters of embryos in two of the cores and only single embryos in the other two. This is one of the first times that multiple embryos have been observed in individual cores at this early stage of stellar development.

About the Object	Object Name: Messier 20 - Trifid Nebula Object Type: Nebula Position (J2000): RA: 18h02m23.4s Dec: -23d01m50.1s Distance: 5,500 light-years or 1.67 kpc Constellation: Sagittarius
About the Data	Image Credit: NASA/JPL-Caltech/J.Rho(SSC/Caltech) Instrument: IRAC, MIPS Wavelength:    IRAC: 3.6, 4.5, 5.8, and 8.0 microns    MIPS: 24 microns Exposure Date:    IRAC: 2004-03-31    MIPS: 2004-04-11 Exposure Time:    IRAC: 8 sec per sky position    MIPS: 48sec per sky position Image Scale: about 20 x 25 arcmin Orientation: Release Date: 12 January 2005
Observers	J. Rho - Principal Investigator (Spitzer Science Center/Caltech) W. T. Reach (Spitzer Science Center/Caltech) B. Lefloch (Laboratoire d'Astrophysique, Observatoire de Grenoble) G. Fazio (Harvard-Smithsonian Center for Astrophysics)

Individual Images

	Visible-Light Image. Screen-Resolution (450x450): JPEG High-Resolution (2958x2958): JPEG | Mac TIFF | PC TIFF Credit: NOAO
	Visible-Light Image. Screen-Resolution (450x401): JPEG High-Resolution (1231x1096): JPEG | Mac TIFF | PC TIFF Credit: NASA/HST
	Visible-Light Image with Inset. Screen-Resolution (450x450): JPEG High-Resolution (2958x2958): JPEG | Mac TIFF | PC TIFF Credit: NOAO
	Spitzer IRAC Infrared Image (Upsampled). Screen-Resolution (450x450): JPEG High-Resolution (2958x2958): JPEG | Mac TIFF | PC TIFF Credit: NOAO
	Wider-View Spitzer IRAC Infrared Image (Not Upsampled). Screen-Resolution (288x450): JPEG High-Resolution (1136x1774): JPEG | Mac TIFF | PC TIFF Credit: NASA/JPL-Caltech/J. Rho (SSC/Caltech)

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