Caldwell 74 : 無料・フリー素材/写真
Caldwell 74 / NASA Hubble
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
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| 説明 | Caldwell 74 looks like a mystic, glowing lake floating in the cosmos, but its true identity is even stranger. Also known as the Southern Ring or Eight-Burst Nebula, this formation is debris from a dying Sun-like star. When medium-mass stars run out of the nuclear fuel that powers them, they eject their outer layers of gas into space. The gaseous shell then expands outward from the remaining core of the star, known as a white dwarf. Objects like this are called planetary nebulae, but only because early astronomers thought they resembled planetary orbs when seen through a small telescope — not because of any real relation to planets.This nebula was produced by a star that is part of a binary, or double star, system. A bright star lies near the center of this Hubble image, but it’s actually the tiny star just above it that produced the nebula. A flood of ultraviolet radiation from the small white dwarf’s surface makes the surrounding gases fluoresce. The brighter star is in an earlier stage of stellar evolution, but in the future it will probably share a similar fate.This image was taken using Hubble’s Wide Field and Planetary Camera 2. In this view, the colors illustrate the temperature of the gases, with blue representing the hottest gas and red representing the cooler gas at the outer edge. The Hubble image also reveals a host of dusty filaments that have condensed out of the expanding gases. Eons from now, these dusty particles may be recycled into new stars and planets.A similar structure, known as the Ring Nebula or Messier 57, can be found in the northern constellation Lyra. The Southern Ring is its Southern Hemisphere counterpart, located in the constellation Vela. It was discovered by English astronomer John Herschel in 1835 and is also cataloged as NGC 3132. The magnitude-9.4 nebula is 2,000 light-years away and only about 0.4 light-years wide, so it can be somewhat challenging to observe with a small telescope. It is best viewed in autumn skies in the Southern Hemisphere. In the Northern Hemisphere, only southern stargazers will have a chance at spotting Caldwell 74, low in springtime skies.For more information about Hubble’s observations of Caldwell 74, see:hubblesite.org/contents/news-releases/1998/news-1998-39.h...Credit: Hubble Heritage Team (STScI/AURA/NASA/ESA)For Hubble's Caldwell catalog website and information on how to find these objects in the night sky, visit: www.nasa.gov/content/goddard/hubble-s-caldwell-catalog |
| 撮影日 | 2019-12-12 20:59:12 |
| 撮影者 | NASA Hubble |
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