Starship Asterisk*

bystander wrote: ↑Mon Aug 31, 2020 3:49 pm A Tilted Wonder
ESA Hubble Picture of the Week | 2020 Aug 31

Image Credit: ESA/Hubble & NASA, R. Tully

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The blue and orange stars of the faint galaxy named NGC 2188 sparkle in this image taken with the NASA/ESA Hubble Space Telescope. Although NGC 2188 appears at first glance to consist solely of a narrow band of stars, it is classified by astronomers as a barred-spiral galaxy. It appears this way from our viewpoint on Earth as the centre and spiral arms of the galaxy are tilted away from us, with only the very narrow outer edge of the galaxy’s disc visible to us. Astronomers liken this occurrence to turning a dinner plate in your hands so you see only its outer edge. The true shape of the galaxy was identified by studying the distribution of the stars in the inner central bulge and outer disc and by observing the stars’ colours.

NGC 2188 is estimated to be just half the size of our Milky Way, at 50 000 light-years across, and it is situated in the northern hemisphere constellation of Columba (The Dove). Named in the late 1500s after Noah’s dove in biblical stories, the small constellation consists of many faint yet beautiful stars and astronomical objects.

Susanna Kohler wrote:

These stills from a 2D hydrodynamic simulation show how a ring of dust and gas surrounding a newly born star might behave as it evolves. The frames illustrate the dust-to-gas ratio after 260 (left), 600 (center), and 1,740 (right) orbits of the dusty ring around the star. These simulations were conducted as part of a study led by Pinghui Huang (Chinese Academy of Sciences and Tsinghua University, China; Los Alamos National Laboratory; Rice University). The results demonstrate how such a ring can become unstable at its edges, forming small vortices that develop into many clumps of dust. Each of these clumps contains at least 10% of Earth’s mass, potentially forming the seeds from which baby planets can grow in the environment around the young star. For more information on the authors’ results, check out the original article below.

• Astrophysical Journal 893(2):89 (2020 Apr 20) DOI: 10.3847/1538-4357/ab8199
• arXiv.org > astro-ph > arXiv:2001.06986 > 20 Jan 2020

Image Credit: ESA/Hubble & NASA, R. Tully

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The blue and orange stars of the faint galaxy named NGC 2188 sparkle in this image taken with the NASA/ESA Hubble Space Telescope. Although NGC 2188 appears at first glance to consist solely of a narrow band of stars, it is classified by astronomers as a barred-spiral galaxy. It appears this way from our viewpoint on Earth as the centre and spiral arms of the galaxy are tilted away from us, with only the very narrow outer edge of the galaxy’s disc visible to us. Astronomers liken this occurrence to turning a dinner plate in your hands so you see only its outer edge. The true shape of the galaxy was identified by studying the distribution of the stars in the inner central bulge and outer disc and by observing the stars’ colours.

NGC 2188 is estimated to be just half the size of our Milky Way, at 50 000 light-years across, and it is situated in the northern hemisphere constellation of Columba (The Dove). Named in the late 1500s after Noah’s dove in biblical stories, the small constellation consists of many faint yet beautiful stars and astronomical objects.

Image Credit: ESO/Petr Horálek

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This image shows a beautiful nighttime scene at ESO’s Paranal Observatory in Chile.

The bright band of the Milky Way cuts prominently through the centre of the scene, crammed with bright gas, dark dust, and sparkling stars, seemingly diving downwards to meet the glowing horizon. The boxy structure of UT1 (Antu), one of the four Unit Telescopes comprising the ESO’s Very Large Telescope (VLT), can be seen at the centre of the frame, while a smaller Auxiliary Telescope is visible to the right, its dome wide open as it scans the skies. With its eight telescopes, four of which — the auxiliaries — are movable, the VLT can act as a highly sensitive interferometer — so sensitive, in fact, that it can distinguish between the two headlights of a car at the distance of the Moon!

The beautiful and oft-photographed skies above the VLT are some of the clearest in the world, as witnessed here by the detail in the Milky Way and obvious brightness of Jupiter, the large object to the left of the image. The greenish tint on the horizon is a phenomenon known as airglow — the faint emission of light from chemiluminescence in the atmosphere. Airglow, and other atmospheric effects such as turbulence, are the principal motivation behind space telescopes such as the NASA/ESA Hubble Space Telescope, which observe high above the frustrating optical distortions caused by our atmosphere.

bystander wrote: ↑Mon Aug 24, 2020 3:16 pm At the Edge of the Blast
ESA Hubble Picture of the Week | 2020 Aug 24

Image Credit: ESA/Hubble & NASA, W. Blair

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While appearing as a delicate and light veil draped across the sky, this image from the NASA/ESA Hubble Space Telescope actually depicts a small section of the Cygnus supernova blast wave, located around 2400 light-years away. The name of the supernova remnant comes from its position in the northern constellation of Cygnus (The Swan), where it covers an area 36 times larger than the full moon.

The original supernova explosion blasted apart a dying star about 20 times more massive than our Sun between 10 000 and 20 000 years ago. Since then, the remnant has expanded 60 light-years from its centre. The shockwave marks the outer edge of the supernova remnant and continues to expand at around 350 kilometres per second. The interaction of the ejected material and the low-density interstellar material swept up by the shockwave forms the distinctive veil-like structure seen in this image.

Click to view full size image 1 or image 2

Credit: Lister et al.; Sophia Dagnello, NRAO/AUI/NSF

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In this image, made with the National Science Foundation’s Very Long Baseline Array (VLBA), young, radio-emitting jets of material emerge from the core of an elliptical galaxy some 500 million light-years from Earth. After NASA’s Fermi Gamma-ray Space Telescope detected high-energy gamma rays coming from the object, scientists used the VLBA to make high-resolution images of the galaxy, dubbed TXS 0128+554.

This image is a composite of six VLBA images made at observing frequencies ranging from 2.2 GigaHertz (GHz) to 22.2 GHz. The broad lobes on either side of the bright core are the result of jet activity that began roughly 80 years ago. The gap between these lobes and the central region indicates, the scientists said, that the jet activity stopped sometime after that, then resumed about 10 years ago.

“These are among the youngest known jets in such systems, and only a handful are known to emit gamma-rays,” said Matthew Lister, of Purdue University.

The bright edges of the lobes are where the ejected material, moving at about a third the speed of light, impacted material within the galaxy. The bright emitting areas total about 35 light-years across, and are at the core of the galaxy, where a supermassive black hole about one million times the mass of the Sun resides. ...

<< Multi-frequency composite VLBA image of the galaxy TXS 0128+554, 500 million light years from Earth. The image shows young radio jets originating near a supermassive black hole at the core of the galaxy. The jets in this image started about 80 years ago, stopped, then resumed about 10 years ago. Animated sequence indicates the radio frequencies at which the images were made. Higher observing frequencies produce higher resolution, showing smaller details. >>

• Astrophysical Journal 889(2):141 (2020 Aug 20) DOI: 10.3847/1538-4357/aba18d

bystander wrote: ↑Mon Aug 24, 2020 3:07 pm A Phenomenal View of a Phenomenal Spiral
ESO Picture of the Week | VLT | MUSE | 2020 Aug 24

Image Credit: ESO/TIMER Survey

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Time Inference with MUSE in Extragalactic Rings

The MUSE instrument on ESO’s Very Large Telescope (VLT) in Chile has observed NGC 1365, a double-barred spiral galaxy located about 56 million light-years away in the Fornax galaxy cluster, allowing us to construct this spectacular colour image. The galaxy is also known as the Great Barred Spiral Galaxy, after its two central bar-shaped structures, made up of stars.

The two bars of NGC 1365 are a rare phenomenon and are thought to have originated by the combined effects of galaxy rotation and the complex dynamics of the stars. Its largest bar of stars, too large for its structure to be visible in this image, connects its outer spiral arms to its centre. What we can see is the much smaller second bar of stars, nestled within the main bar. It is likely this secondary bar acts independently of the main bar, rotating more rapidly than the rest of the galaxy.

Standing for Multi-Unit Spectroscopic Explorer, the MUSE instrument captured this image in optical and infrared light, showing the gas and dust in the central region of the galaxy. Installed on Yepun, one of the four 8.2-metre telescopes that make up the VLT, the capabilities of this instrument have allowed for some of the most comprehensive and detailed studies of our Universe to date, including surveys of distant galaxies, supermassive black holes and even the source of gravitational waves.

Image Credit: ESA/Hubble & NASA, W. Blair

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While appearing as a delicate and light veil draped across the sky, this image from the NASA/ESA Hubble Space Telescope actually depicts a small section of the Cygnus supernova blast wave, located around 2400 light-years away. The name of the supernova remnant comes from its position in the northern constellation of Cygnus (The Swan), where it covers an area 36 times larger than the full moon.

The original supernova explosion blasted apart a dying star about 20 times more massive than our Sun between 10 000 and 20 000 years ago. Since then, the remnant has expanded 60 light-years from its centre. The shockwave marks the outer edge of the supernova remnant and continues to expand at around 350 kilometres per second. The interaction of the ejected material and the low-density interstellar material swept up by the shockwave forms the distinctive veil-like structure seen in this image.

Image Credit: ESO/TIMER Survey

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Time Inference with MUSE in Extragalactic Rings

The MUSE instrument on ESO’s Very Large Telescope (VLT) in Chile has observed NGC 1365, a double-barred spiral galaxy located about 56 million light-years away in the Fornax galaxy cluster, allowing us to construct this spectacular colour image. The galaxy is also known as the Great Barred Spiral Galaxy, after its two central bar-shaped structures, made up of stars.

The two bars of NGC 1365 are a rare phenomenon and are thought to have originated by the combined effects of galaxy rotation and the complex dynamics of the stars. Its largest bar of stars, too large for its structure to be visible in this image, connects its outer spiral arms to its centre. What we can see is the much smaller second bar of stars, nestled within the main bar. It is likely this secondary bar acts independently of the main bar, rotating more rapidly than the rest of the galaxy.

Standing for Multi-Unit Spectroscopic Explorer, the MUSE instrument captured this image in optical and infrared light, showing the gas and dust in the central region of the galaxy. Installed on Yepun, one of the four 8.2-metre telescopes that make up the VLT, the capabilities of this instrument have allowed for some of the most comprehensive and detailed studies of our Universe to date, including surveys of distant galaxies, supermassive black holes and even the source of gravitational waves.

Susanna Kohler wrote:

This stunning image of the Sun and its corona (click for a closer look) is composited from hundreds of individual frames captured by Nicolas Lefaudeux at the Cerro Tololo Inter-American Observatory in Chile. The occasion: a team effort to image a total solar eclipse in July 2019.

In a recent Research Note led by Christian Lockwood (Williams College), you can read about how the team gathered images (like those composited above) using three different observatories in Chile during the eclipse. Lockwood and collaborators then combined these ground-based images — which had high resolution and a wide field of view — with close-in observations of the solar disk made by space-based satellites.

By putting these overlapping observations together, the team could paint a full picture of the Sun’s tenuous, extended outer atmosphere during solar minimum. To learn more about the project, check out the article below.

• Research Notes of the AAS 4(8):133 (2020 Aug 07) DOI: 10.3847/2515-5172/abacb5

Image Credit: ESA/Hubble & NASA, S. Smartt et al

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This image from the NASA/ESA Hubble Space Telescope features the spectacular galaxy NGC 2442.

This galaxy was host to a supernova explosion, known as SN2015F, that was created by a white dwarf star. The white dwarf was part of a binary star system and syphoned mass from its companion, eventually becoming too greedy and taking on more than it could handle. This unbalanced the star and triggered runaway nuclear fusion that eventually led to an intensely violent supernova explosion.

SN2015F was spotted in March 2015 in the galaxy named NGC 2442, nicknamed the Meathook Galaxy owing to its extremely asymmetrical and irregular shape. The supernova shone brightly for quite some time and was easily visible from Earth through even a small telescope until later that summer.