Found images: 2017 July

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starsurfer
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Re: Found images: 2017 July

Postby starsurfer » Sat Jul 15, 2017 10:27 am

CG 2
http://www.capella-observatory.com/ImageHTMLs/DiffuseNebula/CG2.htm
Copyright: Ernst von Voigt and Dietmar Böcker
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bystander
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ESO: Billions of New Neighbours? (RCW 38)

Postby bystander » Mon Jul 17, 2017 1:40 pm

Billions of New Neighbours?
ESO Picture of the Week | 2017 Jul 17

The objects that astronomers call brown dwarfs sit somewhere between the definition of a planet and a star. They are balls of gas with more mass than a planet, but not enough mass to sustain stable hydrogen fusion like a star. Because they hardly emit any visible light, they were only first discovered in 1995 and up until today the majority of known brown dwarfs are within 1500 light-years of us.

Now, astronomers using the NACO adaptive optics infrared camera on ESO’s Very Large Telescope have observed the star cluster RCW 38 in the constellation Vela (the Sail), about 5500 light-years away. This Picture of the Week shows the the central part of RCW 38; the inserts on the sides show a subset of the brown dwarf candidates detected within the cluster.

The scientists found half as many brown dwarfs as stars in the cluster. From these results and from studying other star clusters, the astronomers estimate that the Milky Way contains at least between 25 to 100 billion brown dwarfs. RCW 38 probably contains even more less massive, fainter brown dwarfs, which are beyond the detection limits of this image — so this new estimate could actually be a significant underestimation. Further surveys will reveal the true number of brown dwarfs lurking in the Milky Way.

viewtopic.php?t=37359#p272709
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HEIC: Dim and Diffuse (NGC 4242)

Postby bystander » Mon Jul 17, 2017 1:46 pm

Dim and Diffuse
ESA Hubble Picture of the Week | 2017 Jul 17

Tucked away in the small northern constellation of Canes Venatici (The Hunting Dogs) is the galaxy NGC 4242, shown here as seen by the NASA/ESA Hubble Space Telescope. The galaxy lies some 30 million light-years from us. At this distance from Earth, actually not all that far on a cosmic scale, NGC 4242 is visible to anyone armed with even a basic telescope (as British astronomer William Herschel found when he discovered the galaxy in 1788).

This image shows the galaxy’s bright centre and the surrounding dimmer and more diffuse “fuzz”. Despite appearing to be relatively bright in this image, studies have found that NGC 4242 is actually relatively dim (it has a moderate-to-low surface brightness and low luminosity) and also supports a low rate of star formation. The galaxy also seems to have a weak bar of stars cutting through its asymmetric centre, and a very faint and poorly-defined spiral structure throughout its disc. But if NGC 4242 is not all that remarkable, as with much of the Universe, it is still a beautiful and ethereal sight.
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
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starsurfer
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Re: Found images: 2017 July

Postby starsurfer » Mon Jul 17, 2017 2:14 pm

NGC 6726-7
http://www.tvdavisastropics.com/astroimages-1_000054.htm
Copyright: Thomas Davis
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Re: Found images: 2017 July

Postby starsurfer » Mon Jul 17, 2017 2:17 pm

P Cygni nebula
http://www.cxielo.ch/gallery/f/p-cygni
Copyright: Martin Rusterholz
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Ann
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Re: ESO: Billions of New Neighbours? (RCW 38)

Postby Ann » Mon Jul 17, 2017 4:44 pm

bystander wrote:Billions of New Neighbours?
ESO Picture of the Week | 2017 Jul 17

The objects that astronomers call brown dwarfs sit somewhere between the definition of a planet and a star. They are balls of gas with more mass than a planet, but not enough mass to sustain stable hydrogen fusion like a star. Because they hardly emit any visible light, they were only first discovered in 1995 and up until today the majority of known brown dwarfs are within 1500 light-years of us.

Now, astronomers using the NACO adaptive optics infrared camera on ESO’s Very Large Telescope have observed the star cluster RCW 38 in the constellation Vela (the Sail), about 5500 light-years away. This Picture of the Week shows the the central part of RCW 38; the inserts on the sides show a subset of the brown dwarf candidates detected within the cluster.

The scientists found half as many brown dwarfs as stars in the cluster. From these results and from studying other star clusters, the astronomers estimate that the Milky Way contains at least between 25 to 100 billion brown dwarfs. RCW 38 probably contains even more less massive, fainter brown dwarfs, which are beyond the detection limits of this image — so this new estimate could actually be a significant underestimation. Further surveys will reveal the true number of brown dwarfs lurking in the Milky Way.

viewtopic.php?t=37359#p272709


I have nothing much to say about the brown dwarfs, but here is some info on the rest of RCW 38:

Scott J. Wolk, Tyler L. Bourke, Miquela Vigil wrote:

RCW~38 is a uniquely young (<1 Myr), embedded (AV∼10) stellar cluster surrounding a pair of early O stars (∼O5.5) and is one of the few regions within 2 kpc other than Orion to contain over 1000 members. X-ray and deep near-infrared observations reveal a dense cluster with over 200 X-ray sources and 400 infrared sources embedded in a diffuse hot plasma within a 1 pc diameter. The central O star has evacuated its immediate surroundings of dust, creating a wind bubble ∼0.1 pc in radius...

RCW~38 appears similar in structure to RCW~49 and M~20 but is at an earlier evolutionary phase. RCW~38 appears to be a blister compact H{\small II} region lying just inside the edge of a giant molecular cloud.


RCW 49. Credit: E. Churchwell (Univ. Wisconsin), JPL, Caltech, NASA
The Trifid Nebula. Photo: Jason Ware.






















So RCW 38 is similar to RCW 49 and the Trifid Nebula. That's interesting, I think!

And perhaps the Trifid Nebula, too, is full of brown dwarfs.

Ann
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starsurfer
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Re: Found images: 2017 July

Postby starsurfer » Tue Jul 18, 2017 8:28 am

Flaming Star Nebula (IC 405), Tadpole Nebula (IC 410) and IC 417
http://www.straightontillmorning.me/Astronomy/Nebula/Colour/i-9wpcVH7/X2
Copyright: Hytham Abu-Safieh
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starsurfer
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Re: Found images: 2017 July

Postby starsurfer » Wed Jul 19, 2017 11:47 am

Abell 82
http://www.pbase.com/skybox/image/161687991
Copyright: Kevin Quin
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Re: Found images: 2017 July

Postby starsurfer » Thu Jul 20, 2017 12:17 pm

LBN 215
http://www.capella-observatory.com/ImageHTMLs/DiffuseNebula/LBN215.htm
Copyright: Josef Pöpsel and Stefan Binnewies
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