女巫頭星雲(Witch Head Nebula)，是一個依照它的形狀而命名的反射星雲，它位於波江座內，而且受到亮星參宿七 (Rigel)的影響，女巫頭星雲的正式的名稱為IC 2118。
基本介紹
中文名：女巫頭星雲
外文名：Witch Head Nebula
赤經：5h 1m 60.00s
赤緯：-8° 5′ 60.00″
大小：1.500′
簡介,相關,
簡介
在亮星參宿七的照射下，女巫頭星雲(Witch Head Nebula)好像一縷煙霧貫穿波江星座。波市道戒江星座距離地球約700光年，是個蜿蜒的、在南北方向延伸的星座，位於獵戶座的西南方向，拉丁語名稱為Eridanus,，意為河流，是義大利的波河在神話中的名字。星雲促艱喇會發光，是因為備翻星雲內微細求奔再夜的塵埃，反射參宿七的星光所形成的。女巫頭星雲的顏色是藍色的，這不只是因為參宿七是藍色的，而且也是因為星際塵埃的顆粒，對藍光的散射效率比紅光要好。這與地球白天的天空是藍色的道理是一樣的，只是散射源不同而已；地球的藍天是由陽光經由空氣中的氮分子與氧分子散射所造成的。這霸舉估個星雲與地球相距約1000光年。NASA公布的女巫頭星雲照片
相關
NASA 美國宇航局每日一圖（2008.04.08）
Southern Orion: From Belt to Witch
Explanation: Do you recognize the belt of Orion in this image? The familiar trio of stars, visible to the unaided eye, can be found across the upper left. Otherwise, the southern part of the constellation Orion has taken on a new look inthis unusually deep and wide view First note that the lower left belt star, Alnitak, is the easternmost star in Orion's belt. Left of Alnitak is the Flame Nebula, with clouds of bright emission and dramatic dark dust lanes. Directly belowAlnitak, a close inspection will reveal the Horsehead Nebula. Farther right and below is the Orion Nebula, M42, itself visible to the unaided eye. The brightest star in the frame, near the bottom right, is Rigel. A bright blue star, Rigelilluminates the ominously shaped dust patch known as the Witch Head Nebula, visible as the blue reflection nebula near the lower right corner. Finally, appearing as a vast red ring and encompassing the entire region, is Barnard's Loop.Humans could see this entire menagerie, unaided, were their eyes about 10,000 times more sensitive.
By starlight this eerie visage shines in the dark, a crooked profile evoking its popular name, the Witch Head Nebula. In fact, this entrancing telescopic portrait gives the impression the witch has fixed her gaze on Orion's bright supergiant star Rigel. Spanning over 50 light-years, the dusty cosmic cloud strongly reflects nearby Rigel's blue light, giving it the characteristic color of a reflection nebula. Cataloged as IC 2118, the Witch Head Nebula is about 1,000 light-years away. Of course, you might see a witch this scary tonight, but don't panic. Have a safe and Happy Halloween!
Explanation: Double, double toil and trouble; Fire burn, and cauldron bubble -- maybe Macbeth should have consulted the Witch Head Nebula. This suggestively shaped reflection nebula on the lower left is associated with the bright star Rigel, to its right, in the constellation Orion. More
formally known as IC 2118, the Witch Head Nebula glows primarily by light reflected from Rigel. Fine dust in the nebula reflects the light. Pictured above, the blue color of the Witch Head Nebula and of the dust surrounding Rigel is caused not only by Rigel's blue color but because the dust grains reflect blue light more efficiently than red. The same physical process causes Earth's daytime sky to appear blue, although the scatterers in Earth's atmosphere are molecules of nitrogen and oxygen. Rigel, the Witch Head Nebula, and gas and dust that surrounds them lie about 800 light-years away.
Explanation: Double, double toil and trouble; Fire burn, and cauldron bubble -- maybe Macbeth should have consulted the Witch Head Nebula. This suggestively shaped reflection nebula is associated with the bright star Rigel in the constellation Orion. More formally known as IC 2118, the Witch Head Nebula glows primarily by light reflected from bright star Rigel, located just below the lower edge of the above image. Fine dust in the nebula reflects the light. The blue color is caused not only by Rigel's blue color but because the dust grains reflect blue light more efficiently than red. The same physical process causes Earth's daytime sky to appear blue, although the scatterers in Earth's atmosphere are molecules of nitrogen and oxygen. The nebula lies about 1000 light-years away.
說明：雙雙而至的圈套及困擾、熊熊烈焰和沸騰的氣泡 － 這一切，也許只有麥克白（莎士比亞悲劇《麥克白》中的主人公）才能與女巫頭星雲溝通。這個因形狀而得名的反射星雲正式編號為 IC 2118，與獵戶座中的亮星參宿七有著不解之緣，它所反射的光芒主要就來自參宿七，它恰好位於上圖的下邊緣之外。星雲中的細微塵埃能反射星光，但它顯示出的藍色並非只是因參宿七發出藍光，而是由於塵埃顆粒反射藍光的效率比紅光更高。同樣的物理原理也造成了地球天空在白天看上去是藍色的，只不過地球大氣中的散射源是氮氣及氧氣分子。女巫頭星雲距離我們約1000光年。NASA每日一圖(2012.01.17)
By starlight this eerie visage shines in the dark, a crooked profile evoking its popular name, the Witch Head Nebula. In fact, this entrancing telescopic portrait gives the impression the witch has fixed her gaze on Orion's bright supergiant star Rigel. Spanning over 50 light-years, the dusty cosmic cloud strongly reflects nearby Rigel's blue light, giving it the characteristic color of a reflection nebula. Cataloged as IC 2118, the Witch Head Nebula is about 1,000 light-years away. Of course, you might see a witch this scary tonight, but don't panic. Have a safe and Happy Halloween!
Explanation: Double, double toil and trouble; Fire burn, and cauldron bubble -- maybe Macbeth should have consulted the Witch Head Nebula. This suggestively shaped reflection nebula on the lower left is associated with the bright star Rigel, to its right, in the constellation Orion. More
formally known as IC 2118, the Witch Head Nebula glows primarily by light reflected from Rigel. Fine dust in the nebula reflects the light. Pictured above, the blue color of the Witch Head Nebula and of the dust surrounding Rigel is caused not only by Rigel's blue color but because the dust grains reflect blue light more efficiently than red. The same physical process causes Earth's daytime sky to appear blue, although the scatterers in Earth's atmosphere are molecules of nitrogen and oxygen. Rigel, the Witch Head Nebula, and gas and dust that surrounds them lie about 800 light-years away.
Explanation: Double, double toil and trouble; Fire burn, and cauldron bubble -- maybe Macbeth should have consulted the Witch Head Nebula. This suggestively shaped reflection nebula is associated with the bright star Rigel in the constellation Orion. More formally known as IC 2118, the Witch Head Nebula glows primarily by light reflected from bright star Rigel, located just below the lower edge of the above image. Fine dust in the nebula reflects the light. The blue color is caused not only by Rigel's blue color but because the dust grains reflect blue light more efficiently than red. The same physical process causes Earth's daytime sky to appear blue, although the scatterers in Earth's atmosphere are molecules of nitrogen and oxygen. The nebula lies about 1000 light-years away.
說明：雙雙而至的圈套及困擾、熊熊烈焰和沸騰的氣泡 － 這一切，也許只有麥克白（莎士比亞悲劇《麥克白》中的主人公）才能與女巫頭星雲溝通。這個因形狀而得名的反射星雲正式編號為 IC 2118，與獵戶座中的亮星參宿七有著不解之緣，它所反射的光芒主要就來自參宿七，它恰好位於上圖的下邊緣之外。星雲中的細微塵埃能反射星光，但它顯示出的藍色並非只是因參宿七發出藍光，而是由於塵埃顆粒反射藍光的效率比紅光更高。同樣的物理原理也造成了地球天空在白天看上去是藍色的，只不過地球大氣中的散射源是氮氣及氧氣分子。女巫頭星雲距離我們約1000光年。NASA每日一圖(2012.01.17)
NASA公布的女巫頭星雲照片
NASA每日一圖(2008.04.08)
NASA每日一圖(2008.11.31)
NASA每日一圖(2009.12.29)
NASA每日一圖(2012.01.17)