Filament (Nebel)
Als Filament wird in der Astronomie bei nebelhaften interstellaren Wolken eine fadenartig erscheinende Struktur[1] bezeichnet.
Häufig weisen Supernovaüberreste eine Filamentstruktur auf. Beispiele unterschiedlichen Alters und Ausdehnung sind Cassiopeia A, der Krebsnebel,[2] der Cirrusnebel und der Nebel Simeiz 147, der aufgrund dieses Erscheinungsbildes auch als „Spaghetti-Nebel“ bezeichnet wird. Ursachen für dieses Erscheinungsbild sind Stoßfronten, an denen die Gase ionisiert werden und leuchten, und die um Profil, von der Seite gesehen heller erscheinen, wie man Ende der 1960er Jahre bei einer Untersuchung des Vela-Supernovaüberrestes herausfand.[3] Erste Filamente wurden schon im 19. Jahrhundert beobachtet, ihre Untersuchung kann Aufschluss über den Supernovaüberrest geben.
(c) NASA, ESA, CSA, STScI, D. Milisavljevic (Purdue University), T. Temim (Princeton University), I. De Looze (University of Gent), CC BY 4.0Cassiopeia A, Alter ca. 350 Jahre, ca. 10 Lichtjahre Ausdehnung
Krebsnebel, Alter ca. 1.000 Jahre, Ausdehnung ca. 11 Lichtjahre
Cirrusnebel, Alter im Bereich 8.000–20.000 Jahre, Ausdehnung ca. 150 Lichtjahre
Simeiz 147, Alter ca. 40.000 Jahre, Ausdehnung ca. 220 Lichtjahre
Der Bleistiftnebel ist Teil des Vela-Supernovaüberrestes und wurde im Jahr 1835 entdeckt.![Filament des Cirrusnebels, an dem Geschwindigkeit[4] und ionisierte Gase (OV, NV, CIV, HeII) mithilfe des Hubble-Weltraumteleskops[5] untersucht wurden.](//upload.wikimedia.org/wikipedia/commons/thumb/0/00/Smoke-like_wisps_in_the_Veil_Nebula_by_HST.jpg/120px-Smoke-like_wisps_in_the_Veil_Nebula_by_HST.jpg)
Filament des Cirrusnebels, an dem Geschwindigkeit[4] und ionisierte Gase (OV, NV, CIV, HeII) mithilfe des Hubble-Weltraumteleskops[5] untersucht wurden.
Daneben können auch Molekülwolken eine filamentartige Struktur aufweisen, wie das „Integral-shaped Filament“ im Orion-Molekülwolkenkomplex, in dem der Orionnebel entstanden ist.
Infrarotaufnahme des etwa 100 Lichtjahre ausgedehnten „Integral-shaped Filament“ mithilfe des Herschel-Weltraumteleskops, die die Molekülwolke orange zeigt.
Einzelnachweise
- ↑ filament, Definition in Oxford Dictionary
- ↑ C. O. Lampland: Observed Changes in the Structure of the "Crab" Nebula (N. G. C. 1952). In: Publications of the Astronomical Society of the Pacific. Band 33, Nr. 192, 1921, S. 79, bibcode:1921PASP...33...79L.
- ↑ D. K. Milne: The optical spectrum of Vela X. In: Australian Journal of Physics. Band 21, 1968, S. 501, bibcode:1968AuJPh..21..501M.
- ↑ William P. Blair, Ravi Sankrit, John C. Raymond: Hubble Space Telescope Imaging of the Primary Shock Front in the Cygnus Loop Supernova Remnant. In: The Astronomical Journal. Band 129, 2005, S. 2268–2280, bibcode:2005AJ....129.2268B.
- ↑ Ravi Sankrit, William P. Blair, John C. Raymond, Knox S. Long: Hubble Space Telescope STIS Observations of the Cygnus Loop: Spatial Structure of a Nonradiative Shock. In: The Astronomical Journal. Band 120, 2000, S. 1925–1932, bibcode:2000AJ....120.1925S.
Auf dieser Seite verwendete Medien
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(c) NASA, ESA, CSA, STScI, D. Milisavljevic (Purdue University), T. Temim (Princeton University), I. De Looze (University of Gent), CC BY 4.0
A new high-definition image from the NASA/ESA/CSA James Webb Space Telescope’s NIRCam (Near-Infrared Camera) unveils intricate details of supernova remnant Cassiopeia A (Cas A), and shows the expanding shell of material slamming into the gas shed by the star before it exploded.The most noticeable colours in Webb’s newest image are clumps of bright orange and light pink that make up the inner shell of the supernova remnant. These tiny knots of gas, composed of sulphur, oxygen, argon, and neon from the star itself, are only detectable thanks to NIRCam’s exquisite resolution, and give researchers a hint at how the dying star shattered like glass when it exploded.The outskirts of the main inner shell look like smoke from a campfire. This marks where ejected material from the exploded star is ramming into surrounding circumstellar material. Researchers have concluded that this white colour is light from synchrotron radiation, which is generated by charged particles travelling at extremely high speeds and spiralling around magnetic field lines.There are also several light echoes visible in this image, most notably in the bottom right corner. This is where light from the star’s long-ago explosion has reached, and is warming, distant dust, which glows as it cools down.[Image description: A roughly circular cloud of gas and dust with complex structure. The inner shell is made of bright pink and orange filaments studded with clumps and knots that look like tiny pieces of shattered glass. Around the exterior of the inner shell, there are curtains of wispy gas that look like campfire smoke. Around and within the nebula, various stars are seen as points of blue and white light. Outside the nebula, there are also clumps of dust, coloured yellow in the image.]
Autor/Urheber: Georges Attard, Lizenz: CC BY-SA 4.0
This composite narrow-band image Halpha et OIII, is the remnant of a massive stellar explosion 40000 years ago. It has been the Astronomy Picture Of the Day - APOD- 2020-12-10 https://apod.nasa.gov/apod/ap201210.html
Autor/Urheber: Judy Schmidt, Lizenz: CC BY 2.0
This is the hairy component of the Crab Nebula, in stark contrast to the swirly component. I see no way of illustrating the complete and utter dichotomy of structures contained within this single nebula than to post two separate images of it.
You might be used to seeing the Crab with much different colors. This is a narrowband image and assigning colors to narrowband filters is often done arbitrarily, but I've always found the portrayal of the Crab's colors to be much different from typical color assignments. In this version, you see the central part as quite blue, and that color often represents [O III] but that is not what it is. My version has [O III] represented by blue along with the other two also following in order from shorter to longer wavelengths, which is how I nearly always do these sorts of images. I think a lot of others follow this pattern as well, but it is important to remember that there is no one right way of doing it. For the Hubble release one might argue that it is easier to clearly see the structures with the colors that were used for that image.
Data came from the following proposal: An Emission Line Survey of the Crab Nebula
Red: WFPC2 F673N Green: WFPC2 F631N Blue: WFPC2 F502N
All channels, lightly screened: WFPC2 F547M
North is up.
Autor/Urheber: Credit: ESO, Lizenz: CC BY 3.0
The Pencil Nebula, a strangely shaped leftover from a vast explosion
The oddly shaped Pencil Nebula (NGC 2736) is pictured in this image from ESO’s La Silla Observatory in Chile. This nebula is a small part of a huge remnant left over after a supernova explosion that took place about 11 000 years ago. The image was produced by the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile.
Credit: ESO
About the Image Id: eso1236a Type: Observation Release date: 12 September 2012, 12:00 Related releases: eso1236 Size: 8357 x 8357 px About the Object Name: NGC 2736 Type: • Milky Way : Nebula : Type : Supernova Remnant Distance: 800 light years Coordinates Position (RA): 9h 0m 12.02s Position (Dec): -45° 57' 0.24" Field of view: 33.16 x 33.16 arcminutesOrientation: North is 90.1° left of vertical
A small portion of the Veil Nebula as photographed by the Hubble Space Telescope, showing smoke-like wisps.
Autor/Urheber: Credit ESA/NASA/JPL-Caltech, Lizenz: Attribution
Dusty Orion
The dusty side of the Sword of Orion is illuminated in this striking infrared image from the European Space Agency's Hershel Space Observatory.
This immense nebula is the closest large region of star formation, situated about 1,500 light years away in the constellation of Orion. The parts that are easily observed in visible light, known alternatively as the Orion Nebula or Messier 42, correspond to the light blue regions. This is the glow from the warmest dust, illuminated by clusters of hot stars that have only recently been born in this chaotic region.
The red spine of material running from corner to corner reveals colder, denser filaments of dust and gas that are scattered throughout the Orion nebula. In visible light this would be a dark, opaque feature, hiding the reservoir of material from which stars have recently formed and will continue to form in the future.
Herschel data from the PACS instrument observations, at wavelengths of 100 and 160 microns, is displayed in blue and green, respectively, while SPIRE 250-micron data is shown in red.
Herschel is a European Space Agency mission, with science instruments provided by consortia of European institutes and with important participation by NASA. While the observatory stopped making science observations in April 2013, after running out of liquid coolant as expected, scientists continue to analyze its data. NASA's Herschel Project Office is based at JPL. JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of IPAC, supports the U.S. astronomical community. Caltech manages JPL for NASA.