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ESO: Antu and the Milky Way (VLT)
Posted: Mon Aug 31, 2020 3:40 pm
by bystander
Antu and the Milky Way
ESO Picture of the Week | 2020 Aug 31
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.
HEIC: A Tilted Wonder (NGC 2188)
Posted: Mon Aug 31, 2020 3:49 pm
by bystander
A Tilted Wonder
ESA Hubble Picture of the Week | 2020 Aug 31
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.
AAS: Clumps in a Dusty Ring
Posted: Tue Sep 01, 2020 4:12 pm
by bystander
Clumps in a Dusty Ring
AAS NOVA | Featured Image | 2020 Aug 31
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.
Meso-Scale Instability Triggered by Dust Feedback in Dusty Rings:
Origin and Observational Implications ~ Pinghui Huang
et al
Re: HEIC: A Tilted Wonder (NGC 2188)
Posted: Tue Sep 01, 2020 6:00 pm
by Ann
bystander wrote: ↑Mon Aug 31, 2020 3:49 pm
A Tilted Wonder
ESA Hubble Picture of the Week | 2020 Aug 31
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.
That's a very nice picture!
![Very Happy :D](./images/smilies/icon_biggrin.gif)
Note how the there is considerably more star formation in the upper right part of NGC 2188 than in the lower left part of it. It's not unusual for spiral galaxies to display more star formation in one arm than in the other(s). Note how the star formation of NGC 2188 takes place in a thin disk, but a halo of stars like grains of sand spread out far away from the thin disk.
And note all the superb background galaxies! At left you can see the largest background galaxy, an elegant grand design two-armed barred spiral. That small yellow elliptical galaxy to the left of the grand design one may help shape the big galaxy's spiral arms, just like NGC 5195 helps shape the spiral arms of M51 (seen
here in a photo by Martin Pugh).
Note, too, the halo of NGC 2188 in the upper left part of the picture to the left.
My favorite background galaxy is the galaxy at right in the picture at right. Note how the arms of this galaxy seem to wrap themselves around the bright bar, as if the arms were acrobats wrapping themselves around a pole.
Ann