PIX4619569: Nebula Trifide (M20) in Sagittarius view in visible and infrared - This image composite compares the well - known visible - light picture of the glowing Trifid Nebula (left panel) with infrared views from Nasa's Spitzer Space Telescope (remaining three panels). The Trifid Nebula is a giant star - forming cloud of gas and dust located 5,400 light - years away in the constellation Sagittarius. The false - color Spitzer images reveal a different side of the Trifid Nebula. Where dark lanes of dust are visible trisecting the nebula in the visible - light picture, bright regions of star - forming activity are seen in the Spitzer pictures. All together, Spitzer uncovered 30 massive embryonic stars and 120 smaller newborn stars throughout the Trifid Nebula, in both its dark lanes and luminous clouds. These stars are visible in all the Spitzer images, mainly as yellow or red spots. Embryonic stars are developing stars about to burst into existence. Ten of the 30 massive embryos discovered by Spitzer were found in four dark cores, or stellar “” incubators,””” where stars are born. Astronomers using data from the Institute of Radioastronomy millimeter telescope in Spain had previously identified these cores but thought they were not quite ripe for stars. Spitzer's highly sensitive infrared eyes were able to penetrate all four cores to reveal rapidly growing embryos. Astronomers can actually count the individual embryos tucked inside the cores by looking closely at the Spitzer image taken by its infrared array camera (top right). This instrument has the highest spatial resolution of Spitzer's imaging cameras. The Spitzer image from the multiband imaging photometer (bottom right), on the other hand, specializes in detecting cooler materials. Its view highlights the relatively cool core material falling onto the Trifidi's growing embryos. The middle panel is a combination of Spitzer data from both of these instruments. The embryos are thought to have been triggered by a massiv / Bridgeman Images
PIX4623752: Planetary nebula CRL 2688 dans le Swan/HST - This image of the Egg Nebula, also known as CRL2688 and located roughly 3,000 light - years from us, was taken in red light with the Wide Field and Planetary Camera 2 (WFPC2) aboard Nasa's Hubble Space Telescope.The image shows a pair of mysterious “” searchlight” beams emerging from a hidden star, criss - Yeah. crossed by numerous bright arcs. This image sheds new light on the poorly understood ejection of stellar matter which accompanies the slow death of Sun - like stars. The image is shown in false color. The central star in CRL2688 was a red giant a few hundred years ago. The nebula is really a large cloud of dust and gas ejected by the star, expanding at a speed of 20 km/s (115,000 mph). A dense cocoon of dust (the dark band in the image center) enshrouds the star and hides it from our view. Starlight escapes more easily in directions where the cocoon is thinner, and is reflected towards us by dust particles in the cloud, giving it its overall appearance. Objects like CRL2688 are rare because they are in an evolutionary phase which lasts for a very short time (~ 1,000 to 2,000 years). However, they may hold the key to our understanding of how red giant stars transform themselves into planetary nebulae. For the first time, we can see a 10,000 year - old history of mass - ejection in a red giant star in such exquisite detail. The arcs in CRL2688 represent dense shells of matter within a smooth cloud, and show that the rate of mass ejection from the central star has varied on time scales of ~ 100 to 500 years throughout its mass - loss history. With Hubble we have detected matter in this nebula to a radius of 0.6 light - years - - much further out than has been possible before, giving a better estimate of the amount of matter in the nebula. Other unexpected results seen in this image are the very sharply defined edges of the beams and fine spoke - like features which suggest that, contrary to previous models, the searchli / Bridgeman Images