Found images: 2016 August

[Sandgirl]

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Have you seen a great image or video somewhere that you think would make a great APOD? Nominate it for APOD! Please post as much information here as you have about the image/video with a link to any source(s) for it you know of here, and the editors will take a look.

When posting the image itself, please do not post anything larger than a thumbnail here; please honor the copyright holder's copyright.

Please keep hotlinked images under 400K.

Thank you!

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[bystander]

A Sky Full of Stars (NGC 4833)
ESA Hubble Picture of the Week | 2016 Aug 01

[c][attachment=0]potw1631a[1].jpg[/attachment][/b][/c][hr][/hr]

Located approximately 22 000 light-years away in the constellation of Musca (The Fly), this tightly packed collection of stars — known as a globular cluster — goes by the name of NGC 4833. This NASA/ESA Hubble Space Telescope image shows the dazzling stellar group in all its glory.

NGC 4833 is one of the over 150 globular clusters known to reside within the Milky Way. These objects are thought to contain some of the oldest stars in our galaxy. Studying these ancient cosmic clusters can help astronomers to unravel how a galaxy formed and evolved, and give an idea of the galaxy’s age.

Globular clusters are responsible for some of the most striking sights in the cosmos, with hundreds of thousands of stars congregating in the same region of space. Hubble has observed many of these clusters during its time in orbit around our planet, each as breathtaking as the last.

[starsurfer]

IC 1396
http://www.straightontillmorning.me/Ast ... GbXLXz9/X3
Copyright: Hytham Abu-Safieh

[starsurfer]

Cygnus Milky Way
http://www.nightpixels.net/voie_lactee_stl_lozere.htm
Copyright: Richard Galli

[bystander]

All in a Spin
ESO Picture of the Week | 2016 Aug 01

[img3="Credit: Adhemar M. Duro, Jr. / ESO"]https://cdn.eso.org/images/screen/potw1631a.jpg[/img3][hr][/hr]

Science and art unite in this beautiful photograph, taken in Chile’s Atacama Desert by ESO Photo Ambassador Adhemar M. Duro Jr.

To create this visual masterpiece Adhemar pointed his camera at the sky’s south pole, the point at the centre of all the bright arcs and circles. All the stars in the night sky revolve around this point. Over a period of several hours, this motion creates star trails, with each individual star tracing out a circle on the sky. These trails display the various brightnesses and colours of each star, creating a captivating scene! Towards the top left of the image, you can see a short, bright streak of light cutting across the trails — this is caused by a meteor, burning up in a flash of light as it enters Earth’s atmosphere.

The desert’s harsh and arid landscape, illuminated here by the light from the stars themselves, is the perfect place to view the night sky. Because of the location’s favourable conditions several telescopes are hosted here, including ESO’s Very Large Telescope (VLT), ESO’s Visible and Infrared Survey Telescope for Astronomy (VISTA), and the forthcoming European Extremely Large Telescope (E-ELT), which is currently under construction atop Cerro Armazones.

[starsurfer]

Gum 15
http://www.astro-pics.com/gum15m.html
Copyright: Wolfgang Promper

Click to view full size image

[starsurfer]

NGC 2371-2
http://www.pbase.com/skybox/image/162988550
Copyright: Kevin Quin

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Ou 4
http://www.outters.fr/Ou4_HaOIII_RGB-SV ... avian.html
Copyright: Nicolas Outters

[starsurfer]

NGC 3921
http://www.spacetelescope.org/images/potw1537a/
Copyright: ESA/Hubble & NASA
Acknowledgement: Judy Schmidt

Click to view full size image

[starsurfer]

Ear Nebula (IPHASX J205013.7+465518)
http://www.capella-observatory.com/Imag ... Nebula.htm
Copyright: Makis Palaiologou, Stefan Binnewies and Josef Pöpsel

[Ann]

NGC 3921
http://www.spacetelescope.org/images/potw1537a/
Copyright: ESA/Hubble & NASA
Acknowledgement: Judy Schmidt

Click to view full size image

That's fascinating!

Before the Hubble Space Telescope came along, many galaxies were misclassified. NGC 3921 is one of them, because the NGC-IC Project from 1993 called it an S0-a galaxy. Not so. Its colors are clearly too blue for such a designation. It is a post-merger galaxy instead.

http://www.spacetelescope.org/images/potw1537a/ wrote:
NGC 3921 — found in the constellation of Ursa Major (The Great Bear) — is an interacting pair of disc galaxies in the late stages of its merger. Observations show that both of the galaxies involved were about the same mass and collided about 700 million years ago.

Ann

[Ann]

NGC 7714

Click to view full size image

This galaxy has almost certainly been shown at Starship Asterisk* before, but it is so interesting that I have to post its portrait once again. Do check out this "enhanced" picture of it, which brings out the different components of it so clearly.

What we have is a yellowish disk galaxy with some gas to spare, which has collided with another galaxy and set off a "forest fire" of star formation. We can see the yellow bulge, possibly darkened and reddened by dust, and the incredibly bright starbursting inner ring and nuclear region. We can see spiral arm-like tidal streams of bright blue star clusters. We can see a huge, arc-shaped, galaxy sized "wall" of dark, blue-brown dust, which looks like an enormous shadow. And we can see huge, fuzzy, smooth, yellowish tidal streams of old stars. Frankly, this galaxy has it all: lots of old stars, incredible amounts of dust and fantastic star formation!

We can see it all in the colors of NGC 7714. Its B-V index is 0.520: that's blue, but not remarkable. And that's because NGC 7714 has a large relatively bright yellow population in addition to its brilliant blue young stars.

The U-B of NGC 7714 is −0.450. That's fantastically ultraviolet! And that's because this galaxy is bursting with new stars!

The far infrared magnitude of NGC 7714 is almost two and a half magnitudes brighter than the galaxy's B magnitude. That's because this galaxy is dusty indeed!

That's fantastic! You can look at the galaxy, marvel at its amazing components and confirm it all by checking out its colors. NGC 7714 is a brilliant example of a galaxy whose color indexes so perfectly reflect its visual appearance!

Ann

[bystander]

Squaring up to the Sky
ESO Picture of the Week | 2016 Aug 08

[img3="Credit: Yuri Beletsky (LCO)/ESO"]https://cdn.eso.org/images/screen/potw1632a.jpg[/img3][hr][/hr]

Illuminated only by the impressive nighttime sky, one of ESO’s Very Large Telescope (VLT) Unit Telescopes is an imposing feature in this Picture of the Week.

The VLT is one of the largest and most sophisticated astronomical installations in the world. It consists of four identical Unit Telescopes, each with a main mirror of 8.2 metres in diameter. While each is a large telescope in its own right, by combining the light from all telescopes on the platform — a configuration known as an interferometer — the array in its longest baseline can resolve celestial objects 25 times finer than is possible by using one of the telescopes on its own.

The VLT is situated 2635 metres above sea level in Chile’s Atacama Desert, where the amount of water vapour in the atmosphere is low enough to permit the VLT to observe infrared, as well as visible, light. The spectacular observing conditions at the site are illustrated by the magnificent display of stars in this image. The Milky Way traces a colourful path across the top right of the image, where the dust lanes and star-forming regions of our home galaxy are clearly visible.

[bystander]

A Lopsided Lynx (NGC 2337)
ESA Hubble Picture of the Week | 2016 Aug 08

[img3="Credit: ESA/Hubble & NASA"]https://cdn.spacetelescope.org/archives ... w1632a.jpg[/img3][hr][/hr]

This galaxy, known as NGC 2337, resides 25 million light-years away in the constellation of Lynx. NGC 2337 is an irregular galaxy, meaning that it — along with a quarter of all galaxies in the Universe — lacks a distinct, regular appearance. The galaxy was discovered in 1877 by the French astronomer Édouard Stephan who, in the same year, discovered the galactic group Stephan’s Quintet (heic0910i).

Although irregular galaxies may never win a beauty prize when competing with their more symmetrical spiral and elliptical peers, astronomers consider them to be very important. Some irregular galaxies may have once fallen into one of the regular classes of the Hubble sequence, but were warped and deformed by a passing cosmic companion. As such, irregular galaxies provide astronomers with a valuable opportunity to learn more about galactic evolution and interaction.

Despite the disruption, gravitational interactions between galaxies can kickstart star formation activity within the affected galaxies, which may explain the pockets of blue light scattered throughout NGC 2337. These patches and knots of blue signal the presence of young, newly formed, hot stars.

[starsurfer]

NGC 7714

Click to view full size image

This galaxy has almost certainly been shown at Starship Asterisk* before, but it is so interesting that I have to post its portrait once again. Do check out this "enhanced" picture of it, which brings out the different components of it so clearly.

What we have is a yellowish disk galaxy with some gas to spare, which has collided with another galaxy and set off a "forest fire" of star formation. We can see the yellow bulge, possibly darkened and reddened by dust, and the incredibly bright starbursting inner ring and nuclear region. We can see spiral arm-like tidal streams of bright blue star clusters. We can see a huge, arc-shaped, galaxy sized "wall" of dark, blue-brown dust, which looks like an enormous shadow. And we can see huge, fuzzy, smooth, yellowish tidal streams of old stars. Frankly, this galaxy has it all: lots of old stars, incredible amounts of dust and fantastic star formation!

We can see it all in the colors of NGC 7714. Its B-V index is 0.520: that's blue, but not remarkable. And that's because NGC 7714 has a large relatively bright yellow population in addition to its brilliant blue young stars.

The U-B of NGC 7714 is −0.450. That's fantastically ultraviolet! And that's because this galaxy is bursting with new stars!

The far infrared magnitude of NGC 7714 is almost two and a half magnitudes brighter than the galaxy's B magnitude. That's because this galaxy is dusty indeed!

That's fantastic! You can look at the galaxy, marvel at its amazing components and confirm it all by checking out its colors. NGC 7714 is a brilliant example of a galaxy whose color indexes so perfectly reflect its visual appearance!

Ann

All that's missing from this superb image is its partner in crime NGC 7715.

[starsurfer]

Gum 14
http://www.glitteringlights.com/Images/ ... 2vS77dL/X3
Copyright: Marco Lorenzi

Somewhere in this image the planetary nebula Hen 2-11 can be found! Also features a guest appearance of the reflection nebula NGC 2626.

[Ann]

A Lopsided Lynx (NGC 2337)
ESA Hubble Picture of the Week | 2016 Aug 08

[img3="Credit: ESA/Hubble & NASA"]https://cdn.spacetelescope.org/archives ... w1632a.jpg[/img3][hr][/hr]

This galaxy, known as NGC 2337, resides 25 million light-years away in the constellation of Lynx. NGC 2337 is an irregular galaxy, meaning that it — along with a quarter of all galaxies in the Universe — lacks a distinct, regular appearance. The galaxy was discovered in 1877 by the French astronomer Édouard Stephan who, in the same year, discovered the galactic group Stephan’s Quintet (heic0910i).

Although irregular galaxies may never win a beauty prize when competing with their more symmetrical spiral and elliptical peers, astronomers consider them to be very important. Some irregular galaxies may have once fallen into one of the regular classes of the Hubble sequence, but were warped and deformed by a passing cosmic companion. As such, irregular galaxies provide astronomers with a valuable opportunity to learn more about galactic evolution and interaction.

Despite the disruption, gravitational interactions between galaxies can kickstart star formation activity within the affected galaxies, which may explain the pockets of blue light scattered throughout NGC 2337. These patches and knots of blue signal the presence of young, newly formed, hot stars.

I find this image interesting but frustrating. It is beautiful and elegant but frustratingly non-informative when it comes to the galaxy's color.

My software offers no color information on NGC 2337, except that it tells me that the galaxy's far infrared magnitude is a little more than half a magnitude brighter than the galaxy's B magnitude. This does suggest a healthy amount of star formation, but it is still hard to say how much.

The picture doesn't offer much color information, either. The filters used for this image were a broadband filter centered on 606 nm (orange) and an infrared filter centered at 814 nm. Such filters are clearly bad at picking out blue stars. What we can see is that the galaxy appears to be dominated by a relatively bright, well-established disk of yellow stars. Then there are a few blue-looking clusters and nebulas, one of them really bright, and long faint tangled streamers of yellow and blue stars. I guess the really bright-looking nebula must contain some really hot stars, but many of the other blue-looking stars might just belong to late spectral class B, like Regulus. In fact, they may be even cooler.

If I were to guess at the B-V of this galaxy, I'd say that it looks as if it was not much bluer than 0.6, an unremarkable color index for an irregular dwarf galaxy. But if other filters had been used for the image, I might have guessed at considerably bluer colors.

Ann

[starsurfer]

Fr 2-24
http://astrodonimaging.com/gallery/fr-2-24/
Copyright: Don Goldman

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Longmore 1
http://www.chart32.de/index.php/component/k2/item/185
Copyright: CHART32
Processing: Johannes Schedler

Click to view full size image

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vdB64
http://www.astrophoton.com/vdb064.htm
Copyright: CEDIC
Processing: Bernhard Hubl

Click to view full size image

[starsurfer]

NGC 6894
http://www.pbase.com/dsantiago/image/163765981
Copyright: Derek Santiago

[bystander]

Turbulent Border
ESO Picture of the Week | 2016 Aug 15

[img3="Credit: ESO/Goicoechea et al."]https://cdn.eso.org/images/screen/potw1633a.jpg[/img3][hr][/hr]

These images show the edge of the vast molecular cloud that lies behind the Orion Nebula, 1400 light-years from Earth. The image of the left shows a wide-field view of the region, as seen with the HAWK-I instrument, installed at the Very Large Telescope. A small region is highlighted with a white rectangle, and the rightmost image shows that region in stunning fiery detail, observed with the Atacama Large Millimeter/submillimeter Array (ALMA).

As well as producing beautiful images, molecular clouds are of great interest to astronomers. The clouds are stellar nurseries and at their edge atoms react and form molecules by key astrochemical processes. With the ALMA observations scientists were able to resolve this transition from atomic to molecular gas at the border of the Orion molecular cloud. As Orion is the nearest massive star-forming region it is the ideal target to find out more about these astrochemical processes, and it also offers the possibility to study the interactions of newly formed stars with their surroundings in detail.

Both observations show that this fascinating astrochemical transition from atomic to molecular gas happens in a highly dynamic environment. ALMA’s view of the nebula particularly resembles the dark clouds of a huge upcoming storm in Earth’s atmosphere.

Compression and Ablation of the Photo-Irradiated Molecular Cloud the Orion Bar - Javier R. Goicoechea et al

• Nature (online 10 Aug 2016) DOI: 10.1038/nature18957

[bystander]

Stellar Shrapnel
ESA Hubble Picture of the Week | 2016 Aug 15

[img3="ESA/Hubble & NASA, Y. Chu"]https://cdn.spacetelescope.org/archives ... w1633a.jpg[/img3][hr][/hr]

Several thousand years ago, a star some 160 000 light-years away from us exploded, scattering stellar shrapnel across the sky. The aftermath of this energetic detonation is shown here in this striking image from the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3.

The exploding star was a white dwarf located in the Large Magellanic Cloud, one of our nearest neighbouring galaxies. Around 97% of stars within the Milky Way that are between a tenth and eight times the mass of the Sun are expected to end up as white dwarfs. These stars can face a number of different fates, one of which is to explode as supernovae, some of the brightest events ever observed in the Universe. If a white dwarf is part of a binary star system, it can siphon material from a close companion. After gobbling up more than it can handle — and swelling to approximately one and a half times the size of the Sun — the star becomes unstable and ignites as a Type Ia supernova.

This was the case for the supernova remnant pictured here, which is known as DEM L71. It formed when a white dwarf reached the end of its life and ripped itself apart, ejecting a superheated cloud of debris in the process. Slamming into the surrounding interstellar gas, this stellar shrapnel gradually diffused into the separate fiery filaments of material seen scattered across this skyscape.

[starsurfer]

Abell 33
https://www.eso.org/public/news/eso1412/
Copyright: ESO

Click to view full size image

[starsurfer]

Hickson 44
http://www.karelteuwen.be/photo_page.ph ... 8&album=14
Copyright: Karel Teuwen