![]() ![]() The astronomer William Herschel (discoverer of the planet Uranus) thought it was the former, once remarking after seeing one, “Here truly is a hole in heaven!” However, American astronomer E. For a long time, astronomers debated whether these dark regions were empty “tunnels” through which we looked beyond the stars of the Milky Way Galaxy into intergalactic space, or clouds of some dark material that blocked the light of the stars beyond. Explain the terms extinction and interstellar reddeningįigure 20.9 shows a striking example of what is actually a common sight through large telescopes: a dark region on the sky that appears to be nearly empty of stars.Understand the role and importance of infrared observations in studying dust.Describe how we can detect interstellar dust.Sorry, the comment form is closed at this time.By the end of this section, you will be able to: This image is taken with the infrared Spitzer Space Telescope. They are usually highly obscured by the clouds of gas and dust from which they formed. Herbig-Haro objects are small nebulae produced by outflows ejected by newly born stars, and are formed when narrow jets of gas ejected by young stars collide with clouds of gas and dust nearby, at speeds of several hundred kilometres per second. There are also 36 Herbig-Haro obejects identified in NGC 1333 confirming its status as a young active region of star formation. It also suggests that objects not much bigger than Jupiter could form the same way as stars do. That difference may be hinting at how different environmental conditions affect their formation. ![]() Brown dwarfs are celestial bodies that are larger than planets but too small to trigger the internal nuclear fusion reactions required to become full-fledged stars.īrown dwarfs seem to be more common in NGC 1333 than in other young star clusters. In contrast, the upper portion of the nebula is dominated by the infrared light from warm dust, shown as red.Īstronomers have discovered 30 to 40 brown dwarfs in NGC 1333 and Rho Ophiuchi Cloud complex together, including one that is just six times the mass of Jupiter. This leads scientists to believe that by stirring up the cold gas, the jets may contribute to the eventual dispersal of the gas cloud, preventing more stars from forming in NGC 1333. The number of separate jets that appear in this region is unprecedented. The greenish streaks and splotches located in the lower portion of the image are glowing shock fronts where jets of material – spewed from extremely young embryonic stars – are plowing into the cold, dense gas nearby. By looking for differences in the disk properties between the two subgroups, they hope to find hints of the star- and planet-formation history of this region. With the sharp infrared eyes of Spitzer, scientists can detect and characterize the warm and dusty disks of material that surround forming stars. The other group is south, where the features shown in yellow and green abound in the densest part of the natal gas cloud. One group is to the northern part of the nebula shown as red in the image. The young stars in NGC 1333 don’t form a single cluster, but are split between two sub-groups. This allows a look through the dust to gain a more detailed understanding of how stars like our Sun begin their lives. With the penetrating infrared view of the Spitzer, scientists can detect the light from these objects. The nebula contains hundreds of these young stars (less than a million years old), most still obscured by the dusty clouds which formed them. ![]() ![]() Star clusters are born within molecular clouds and during their early evolution they are often only visible at infrared wavelengths because they are heavily obscured by dust. It is one of the nearest star forming regions and particularly rich in young stars. It is located only about 1,000 light-years away from Earth in the northern constellation of Perseus, at the edge of the Perseus molecular cloud. NGC 1333 is a diffuse reflection nebula of about 4 light-years across, that is less than a million years old. Gutermuth (Harvard-Smithsonian CfA) et al./JPL-Caltech/NASA ![]()
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