Starship Asterisk*

Guest wrote: ↑Fri Jun 29, 2018 6:55 pm Lensed galaxy
copyright:Judy Schmidt NASA/ESA Hubble
https://twitter.com/SpaceGeck/status/10 ... 2194180097
and https://www.flickr.com/photos/geckzilla/28209513487/

Paper in perperation (see tweet)

Credit: ESA/Hubble & NASA

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This rich and dense smattering of stars is a massive globular cluster, a gravitationally-bound collection of stars that orbits the Milky Way. Globular clusters are denser and more spherical than open star clusters like the famous Pleiades. They typically contain hundreds of thousands of stars that are thought to have formed at roughly the same time.

Studies have shown that this globular cluster, named NGC 6139, is home to an aging population of stars. Most globular clusters orbiting the Milky Way are estimated to be over 10 billion years old; as a result they contain some of the oldest stars in our galaxy, formed very early in the galaxy’s history. However, their role in galactic evolution is still a matter of study.

This cluster is seen roughly in the direction of the centre of the Milky Way, in the constellation of Scorpius (The Scorpion). This constellation is a goldmine of fascinating astronomical objects. Hubble has set its sights on Scorpius many times to observe objects such as the butterfly-like Bug Nebula, surprising binary star systems, and other dazzling globular clusters.

Credit: ESO/L. Jorda et al., P. Vernazza et al.

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Sitting between Mars and Jupiter, the doughnut-shaped asteroid belt is packed full of rocky bodies and debris. Despite its fragmented, rubbly nature, the total mass contained within the belt is considerable — roughly four per cent of that of the Moon! The majority of this mass is contained within two distinctive bodies: Ceres, a dwarf planet estimated to make up a third of the mass of the belt, and the asteroid Vesta, which holds around nine per cent of it. Vesta is pictured here.

Vesta was recently observed by the SPHERE/ZIMPOL instrument on ESO’s Very Large Telescope (VLT) — the SPHERE image is shown on the left, produced using the MISTRAL algorithm, with a synthetic view derived from space-based data shown on the right for comparison. SPHERE, the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument, is a powerful planet-finding and direct imaging instrument. ZIMPOL is one of its subsystems: a specialised camera perfectly suited to taking very sharp images of small objects — like Vesta.

The synthetic image was generated using a tool developed for space missions called OASIS. Factors such as the reflectance of Vesta’s surface and the geometric conditions of the VLT/SPHERE observations where accounted for by OASIS, which used a 3D model of Vesta’s shape based on images from NASA’s Dawn spacecraft (which completed a 14-month survey of Vesta between 2011 and 2012).

SPHERE’s image of Vesta is impressive given the separation between Earth and Vesta, and the small size of the asteroid — it lies twice as far from the Sun as our planet does, and has a mean diameter of just 525 kilometres. It shows Vesta’s main features: the giant impact basin at Vesta's south pole, and the mountain at the bottom right. This is the central peak of the Rheasilvia basin, and is roughly 22 kilometres high — over twice as high as the tallest mountain on Earth, Mauna Kea, which rises roughly 10 kilometres from the basin of the Pacific Ocean floor, and nearing the height of the mammoth Martian volcano Olympus Mons.

Image Credit: ESA/Hubble & NASA, RELICS

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In astronomy, the devil is in the details — as this image, taken by the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys and Wide-Field Camera 3, demonstrates.

The numerous fuzzy blobs and glowing shapes scattered across this image make up a galaxy cluster named RXC J0949.8+1707. Located to the upper right of the frame sits an especially beautiful and interesting barred spiral galaxy, seen face-on. In the past decade, astronomers peering at this galaxy have possibly discovered not one but three examples of a cosmic phenomenon known as a supernova, the magnificently bright explosion of a star nearing the end of its life.

The newest supernova candidate is nicknamed SN Antikythera, and can be seen to the lower right of the host galaxy. This shone brightly in visible and infrared light over a number of years before fading slightly. The two other supernovae, nicknamed SN Eleanor and SN Alexander, were present in data collected in 2011 but are not visible in this image, which was taken a few years later — their temporary nature unambiguously confirmed their status as supernovae. If future observations of RXC J0949.8+1707 show SN Antikythera to have disappeared then we can most likely label it a supernova, as with its two older (and now absent from the images) siblings.

This image was taken as part of an observing programme called RELICS (Reionization Lensing Cluster Survey). RELICS imaged 41 massive galaxy clusters with the aim of finding the brightest distant galaxies for the forthcoming NASA/ESA/CSA James Webb Space Telescope (JWST) to study.

Image Credit: Yuri Beletsky (LCO) / ESO

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In this spectacular shot from northern Chile, the immediately recognisable and magnificent constellation of Orion (The Hunter) peers down on the small walkway connecting ESO’s 3.6-metre telescope to the now-decommissioned Coudé Auxiliary Telescope, both located at ESO’s La Silla Observatory.

A closer look at this long exposure, captured by ESO Photo Ambassador Yuri Beletsky, reveals many interesting features — including a streak of light as an artificial satellite passes behind the telescope’s dome (to the right of the frame). Barnard’s Loop, a faint emission nebula thought to be the remnant of a supernova, appears as a faint reddish arc encircling the bright Orion Nebula. Just below and parallel to the walkway, the dark dust lanes of the Milky Way can be seen rippling across the starry sky.

ESO’s 3.6-metre telescope is equipped with the High Accuracy Radial velocity Planet Searcher (HARPS) instrument, one of the most accurate and productive planet hunters in the history of astronomy.

Ann wrote: ↑Sun Jun 17, 2018 9:12 pm NGC 2997
https://www.adamblockphotos.com/ngc-2997.html
Copyright: Adam Block

Click to view full size image

I am delighted that Adam Block has uploaded a new galaxy image! NGC 2997 is a splendid-looking spiral galaxy of type SBc. Note the elegant dust lanes winding their way deep into the core of the galaxy, the small bright white ring of of star formation encircling the core, the yellow bulge and the blue and pink starforming spiral arms.

Ann