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Blobrana


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RE: Planetary nebulae
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Four different planetary nebulae



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Blobrana


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NGC 5315 is a planetary nebula about 7,000 light years from Earth in the constellation of Circinus. Planetary nebulas are gaseous clouds that are created in the last stages of the lifetime of a star like the Sun. The name of "planetary nebula" is a misnomer, since these objects have nothing to do with planets. But the term was born because these objects look like planets when viewed through small optical telescopes. Chandra does not always see planetary nebulas in X-ray light. Rather, they may only become X-ray sources, like NGC 5315, when powerful winds from a particularly young star at the centre collide with the ejected material.

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NGC 5315
Credit: NASA/CXC/RIT/J. Kastner et al.
JPEG (100.4 kb) Tiff (24.1 MB) PS (7 MB)

Coordinates (J2000) RA 13 h 26m 08s | Dec -29d 52m 24s

-- Edited by Blobrana at 20:58, 2007-09-30

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Blobrana


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NGC 5315
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Title: Serendipitous Chandra X-ray Detection of a Hot Bubble within the Planetary Nebula NGC 5315
Authors: Joel Kastner, Rodolfo Montez, Jr., Bruce Balick, Orsola De Marco

We report the serendipitous detection of the planetary nebula NGC 5315 by the Chandra X-ray Observatory. The Chandra imaging spectroscopy results indicate that the X-rays from this PN, which harbours a Wolf-Rayet (WR) central star, emanate from a T_X ~ 2.5x10^6 K plasma generated via the same wind-wind collisions that have cleared a compact (~8000 AU radius) central cavity within the nebula. The inferred X-ray luminosity of NGC 5315 is ~2.5x10^{32} erg s^{-1} (0.3-2.0 keV), placing this object among the most luminous such "hot bubble" X-ray sources yet detected within PNe. With the X-ray detection of NGC 5315, objects with WR-type central stars now constitute a clear majority of known examples of diffuse X-ray sources among PNe; all such "hot bubble" PN X-ray sources display well-defined, quasi-continuous optical rims. We therefore assert that X-ray-luminous hot bubbles are characteristic of young PNe with large central star wind kinetic energies and closed bubble morphologies. However, the evidence at hand also suggests that processes such as wind and bubble temporal evolution, as well as heat conduction and/or mixing of hot bubble and nebular gas, ultimately govern the luminosity and temperature of superheated plasma within PNe.

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Blobrana


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Planetary nebulae
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The colourful, intricate shapes in these NASA Hubble Space Telescope images reveal how the glowing gas ejected by dying Sun-like stars evolves dramatically over time. These gaseous clouds, called planetary nebulae, are created when stars in the last stages of life cast off their outer layers of material into space. The snapshots of He 2-47, NGC 5315, IC 4593, and NGC 5307 were taken with Hubble's Wide Field Planetary Camera 2 in February 2007.

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Planetary Nebulae.kmz
Google Sky file

-- Edited by Blobrana at 16:09, 2008-01-12

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