NGC 3242
| NGC 3242 | |
 Bild på NGC 3242 tagen med Rymdteleskopet Hubble. Foto: HST/NASA/ESA | |
| Observationsdata | |
|---|---|
| Typ | Planetarisk nebulosa |
| Stjärnbild | Vattenormen |
| Rektascension | 10t 24m 46,11 s[1] |
| Deklination | -18° 38′ 32,6″[1] |
| Avstånd | 4 800 ± 500[2] ljusår |
| Skenbar storlek | 25 bågsekunder |
| Skenbar magnitud | 8,6 |
| Fysiska egenskaper | |
| Radie | 2 ljusår |
| Upptäckt | |
| Upptäcktsår | 7 februari 1785 |
| Upptäckare | William Herschel |
| Andra beteckningar | |
| Jupiters spoke, Caldwell 59, NGC 3242, AT20G J102446-183836, BD-17 3140, ESO 568-5, GC 14298, GCRV 6542, GSC2 S123031352, HD 90255, IRAS 10223-1823, IRAS F10223-1823, JCMTSE J102446.4-183838, JCMTSF J102446.4-183838, 2MASS J10244612-1838321, NSV 4848, NVSS J102446-183832, OHIO L -137.5, PK 261+32 1, PKS J1024-1838, PKS 1022-183, PLX 2442, PLX 2442.00, PMN J1024-1838, PN G261.0+32.0, PN VV 57, PN ARO 4, PN VV' 98, PPM 222919, PSCz P10223-1823, SAO 155965, SCM 55, SKY# 20000, TD1 14821, 2XMM J102446.0-183832, [DML87] 264, AAVSO 1020-18 | |
| Se även: Nebulosor, Lista över nebulosor | |
NGC 3242, även känd som Caldwell 59, är en planetarisk nebulosa belägen i stjärnbilden Vattenormen. Den upptäcktes 7 februari 1835 av William Herschel som katalogiserade den som H IV.27. John Herschel observerade den från Godahoppsudden, Sydafrika, på 1830-talet, och numrerade den som h 3248, och införde den i 1864 års allmänna katalog som GC 2102. Detta blev NGC 3242 i J. L. E. Dreyers nya allmänna katalog från 1888. Den kallas ofta Jupiters Ande eller Jupiters Spöke på grund av dess visuella storlek liknande planetens, men den kallas också ibland Ögonnebulosan.[3]
Egenskaper
NGC 3242 har en bredd av omkring två ljusår och innehåller en central vit dvärg med en skenbar magnitud av 11. Nebulosans inre lager bildades för ca 1 500 år sedan.[4] De två ändarna av nebulosan markeras av FLIERs, lober av snabbt rörlig gas ofta rödtonade i falskt färgade bilder.[5] NGC 3242 kan lätt observeras med amatörteleskop och verkar blågrön för de flesta observatörer. Större teleskop kan också urskilja dess yttre halo.[6]
Galleri
Bild av NGC 3242 med 10-tums Schmidt-Cassegrain-teleskop
Bild på NGC 3242 tagen med Rymdteleskopet Hubble. Foto: HST/NASA/ESA,
Ultraviolet bild från NASA's Galaxy Evolution Explorer
Infraröd bild av Spitzer Space Telescope
Referenser
- Den här artikeln är helt eller delvis baserad på material från engelskspråkiga Wikipedia, NGC 3242, 25 juli 2021.
- Caldwellkatalogen på Hawaiian Astronomical Societys webbsida
- ”NGC 3242” (på engelska). Simbad. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NGC+3242&submit=SIMBAD+search. Läst 7 oktober 2015.
Noter
- ^ [a b] http://simbad.u-strasbg.fr/simbad/sim-id?Ident=NGC++3242. Hämtad 2021-07-25.
- ^ Gaia Collaboration et al. (2018b): Summary of the contents and survey properties
- ^ Frommert, Hartmut. ”NGC 3242”. SEDS. http://spider.seds.org/spider/Misc/n3242.html. Läst 22 juni 2014.
- ^ Mobberley, Martin (2009). The Caldwell Objects and How to Observe Them. New York: Springer Science+Business Media, LLC. sid. 128. ISBN 978-1-4419-0326-6. https://books.google.com/books?id=amPrWoOWgHcC&pg=PA128
- ^ ”NGC 3242, Ghost of Jupiter”. ESA. Arkiverad från originalet den 20 juli 2014. https://web.archive.org/web/20140720003214/http://www.spacetelescope.org/projects/fits_liberator/fitsimages/danny_lacrue_1/. Läst 22 juni 2014.
- ^ ”The Ghost of Jupiter”. http://www.skyhound.com/sh/archive/mar/NGC_3242.html. Läst 25 februari 2010.
Externa länkar
Wikimedia Commons har media som rör NGC 3242.- The Hubble European Space Agency Information Centre – Hubble picture and information on NGC 3242
- NGC3242 on astro-pics.com
- FLIERs in NGC 3242
Media som används på denna webbplats
This ultraviolet image from NASA's Galaxy Evolution Explorer shows NGC 3242, a planetary nebula frequently referred to as "Jupiter's Ghost."
The unfortunate name of "planetary nebula" for this class of celestial object is a historical legacy credited to William Herschel during the 18th century -- a time when telescopes where small and objects like these, at least the central region, looked very similar to gas-giant planets such as Saturn and Jupiter. In fact, NGC 3242 has no relation to Jupiter or any other planet.
Telescopes and their detectors have dramatically improved over the past few centuries. Our understanding of what planetary nebulae truly are has improved accordingly.
When stars with a mass similar to our sun approach the end of their lives by exhausting supplies of hydrogen and helium fuel in their cores, they swell up into cool red-giant stars. In a last gasp before death, they expel the layers of gas in their outer atmosphere. This exposes the core of the dying star, a dense hot ball of carbon and oxygen called a white dwarf. The white dwarf is so hot that it shines very brightly in the ultraviolet. The ultraviolet light from the white dwarf, in turn, ionizes the gaseous material expelled by the star causing it to glow. A planetary nebula is really the death of a low-mass star.
Although low-mass stars like our sun live for billions of years, planetary nebulae only last for about ten thousand years. As the central white dwarf quickly cools and the ultraviolet light dwindles, the surrounding gas also cools and fades.
In this image of NGC 3242 from the Galaxy Evolution Explorer, the extended region around the planetary nebula is shown in dramatic detail. The small circular white and blue area at the center of the image is the well-known portion of the famous planetary nebula. The precise origin and composition of the extended wispy white features is not known for certain. It is most likely material ejected during the star's red-giant phase before the white dwarf was exposed. However, it may be possible that the extended material is simply interstellar gas that, by coincidence, is located close enough to the white dwarf to be energized by it, and induced to glow with ultraviolet light.
NGC 3242 is located 1,400 to 2,500 light-years away in the constellation Hydra. It was discovered by William Herschel in 1785.
This ghostly image from NASA's Spitzer Space Telescope shows the disembodied remains of a dying star, called a planetary nebula. Planetary nebulas are a late stage in a sun-like star's life, when its outer layers have sloughed off and are lit up by ultraviolet light from the central star. The Ghost of Jupiter, also known as NGC 3242, is located roughly 1,400 light-years away in the constellation Hydra. Spitzer's infrared view shows off the cooler outer halo of the dying star, colored here in red. Also evident are concentric rings around the object, the result of material being periodically tossed out in the star's final death throes. In this image, infrared light at wavelengths of 3.6 microns is rendered in blue, 4.5 microns in green, and 8.0 microns in red.
Der recht helle Planetarische Nebel NGC 3242 ist nicht nur visuell ein dankbares Objekt. Auch fotografisch ist er bereits mit einer unmodifizierten Webcam erfaßbar. Die Aufnahme entstand in Bad Tölz am 15.1.2007 um 3:08 MEZ. Aufgenommen wurde mit der ToUcam 840 an einem 10" SCT. Die Brennweite wurde mittels Reducer auf 1.436mm verkürzt.
Författare/Upphovsman: Judy Schmidt, Licens: CC BY 2.0
Another planetary nebula. Very similar to <a href="https://www.flickr.com/photos/geckzilla/9667741870">NGC 6826</a> but it's interesting to compare the subtle differences. Why are they so similar? Why are some parts not similar? Are they <a href="http://hubblesite.org/newscenter/archive/releases/2013/37" rel="nofollow">aligned for some reason</a>?
Processing notes: Most of the nebula was on three filters but the edges were cut off around the outer part of the fainter spheroid. Something like <a href="File:NGC_3242_-HST-_R658G656B502.png" rel="nofollow">this</a> but I used a different set for the WFPC2-PC squares. There's more than one way to process a nebula...
Red: hst_08773_13_wfpc2_f658n_pc_sci Green: hst_08773_13_wfpc2_f555w_pc_sci Blue: hst_08773_13_wfpc2_f502n_pc_sci
Extra bits around the edge that were missing from the PC: hst_10822_02_wfpc2_f547m_wf_sci
North is up.
