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Hubble's dusty laboratory
DR EMILY BALDWIN
ASTRONOMY NOW
Posted: December 1, 2009


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A new image from the Hubble Space Telescope depicting part of the Iris Nebula presents a perfect dust laboratory in which to study the formation of stars.

Close up of an area in the northwest region of the Iris Nebula. Researchers studying the object are particularly interested in the region to the left and slightly above centre in the image, where dusty filaments appear redder than expected. Image: NASA & ESA.

Although cosmic dust can pose a problem to astronomers because visible light cannot penetrate it, studying these thick cocoons of dusty, gaseous material are important since they contain the raw ingredients of stars.

This particularly dusty cloud of cosmic dust is being lit up from above by nearby star HD 200775; both background and foreground stars are dotted throughout the image. Normally, reflection nebulae like this – made of clouds of gas not hot enough to emit light themselves – glow blue because of the way they scatter light, but this part of the Iris Nebula appears unusually red.

A wide-field image of the region around NGC 7023 constructed from Digitized Sky Survey 2 data. The field of view is approximately 2.8 degrees x 2.9 degrees. Image: NASA, ESA and Digitized Sky Survey 2. Acknowledgment: Davide De Martin (ESA/Hubble).

In particular, the region to the left and slightly above centre hosts dusty filaments much redder than expected. Astronomers think that a chemical compound based on hydrocarbons is likely responsible for the red tinge, and are performing ground-based laboratory tests to better assess the exact chemical composition.

The Iris Nebula, or NGC 7023, is in the constellation of Cepheus approximately 1,400 light years from Earth and spans about six light years across. The image was composed using Hubble’s Advanced Camera for Surveys and the Multi-Object Spectrometer (NICMOS) instrument.