This shock wave plows through space at over 500,000 kilometers per hour. Moving right to left in the beautifully detailed color composite, the thin, braided filaments are actually long ripples in a sheet of glowing gas seen almost edge on. Cataloged as NGC 2736, its narrow appearance suggests its popular name, the Pencil Nebula. About 5 light-years long and a mere 800 light-years away, the Pencil Nebula is only a small part of the Vela supernova remnant. The Vela remnant itself is around 100 light-years in diameter, the expanding debris cloud of a star that was seen to explode about 11,000 years ago. Initially, the shock wave was moving at millions of kilometers per hour but has slowed considerably, sweeping up surrounding interstellar gas. (text adapted from APOD).Apo TEC140 (140/f7.2) - FLI Proline 16803 - Ha (330m) OIII (200m) R (90m) G (100m) B (100m) - Warrumbungle Observatory, Coonabarabran, NSW, Australia
Dark shapes with bright edges winging their way through dusty NGC 6188 are tens of light-years long. The emission nebula is found near the edge of an otherwise dark large molecular cloud in the southern constellation Ara, about 4,000 light-years away. Formed in that region only a few million years ago, the massive young stars of the embedded Ara OB1 association sculpt the fantastic shapes and power the nebular glow with stellar winds and intense ultraviolet radiation. The recent star formation itself was likely triggered by winds and supernova explosions, from previous generations of massive stars, that swept up and compressed the molecular gas. At the estimated distance of NGC 6188, the picture spans about 200 light-years. At the right of the image, beautiful emission nebula NGC 6164 was created by a rare, hot, luminous O-type star, some 40 times as massive as the Sun. Seen at the center of the cosmic cloud, the star is a mere 3 to 4 million years old. In another three to four million years the massive star will end its life in a supernova explosion. Spanning around 4 light-years, the nebula itself has a bipolar symmetry. That makes it similar in appearance to more familiar planetary nebulae - the gaseous shrouds surrounding dying sun-like stars. Also like many planetary nebulae, NGC 6164 has been found to have an extensive, faint halo, revealed in this deep telescopic image of the region. Expanding into the surrounding interstellar medium, the material in the halo is likely from an earlier active phase of the O star. NGC 6164 is 4,200 light-years away in the southern constellation of Norma. (text adapted from APOD). Apo TEC140 (140/f7.2) - FLI Proline 16803 - Ha (200m) OIII (480m) R (90m) G (120m) B (150m) - Warrumbungle Observatory, Coonabarabran, NSW, Australia
