|
New images of the North America and Pelican nebula, obtained with the infrared sensors of the Spitzer space telescope, show these spectacular structures in a completely new light. What is seen at the infrared wavelengths of 3.6, 4.5, 5.8, 8 and 24 micron, completely transforms the familiar silhouette of the Gulf of Mexico, apparently populated by very few stars, into a vibrant cauldron of gas and dust surrounding at least a couple of thousand newly born or very young stars.
The images above give some idea (within the limits of their resolution) of the new view of the nebular complex and the wealth of detail that infrared light reveals, thanks to its ability to penetrate the dusty medium that characterises this region.
The gloomy Gulf of Mexico is therefore really a breeding ground for new stars. However, the whereabouts of the massive stars, that provide the energy to heat and illuminate the entire region, remains a mystery. It is likely that these stars are coincident with the brightest patches of infrared light in the Gulf, but the quantity of dust in these regions is too much for even Spitzer's mighty gaze to penetrate.
The enormous quantities of gas and dust are also obstacles for the determination of an accurate distance to the North America and Pelican nebulae. It is currently estimated to be around 1800 light years, but the figure is uncertain due to the irregular filter of the nebulae themselves, making it difficult to distinguish between stars belonging to the nebulae and those that are either infront of, or behind it. This problem could be resolved by the new stars identified by Spitzer, if at least for some of them, it is possible to determine their absolute magnitude, mass and evolutionary phase.
The results of the analysis of these images will be published in the Astrophysical Journal Supplement Series, in an article by Luisa Rebull and colleagues, at NASA's Spitzer Science Center at the California Institute of Technology, Pasadena. |
