Starship Asterisk*

Credit: ESO/R Leaman/D Gadotti/K Sandstrom/D Calzetti

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NGC 3351, also known as Messier 95, was first discovered in 1781 by Pierre Méchain, a French astronomer and surveyor who worked alongside Charles Messier. NGC 3351 is a type of galaxy known as a barred spiral galaxy and it is located in the constellation of Leo (The Lion).

New observations of this object have shown stellar feedback in action. Stellar feedback is the process of redistributing energy into the interstellar medium (the space in between the stars) within star-forming galaxies. In this particular galaxy, star formation is occurring in the ring surrounding the galaxy nucleus at such a violent rate that massive bubbles of hot gas can actually be seen being ejected. This ejected gas can then contribute (both positively and negatively) to ongoing star formation within the galaxy.

The data for this observation were taken with ALMA, the NASA/ESA Hubble Space Telescope and the Very Large Telescope, showing once again that scientific collaboration across multiple facilities can produce some wonderful results.

Credit: NASA/ESA/Hubble; LEGUS team, B Tully, D Calzetti

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This Picture of the Week shows a dwarf galaxy named UGC 685. Such galaxies are small and contain just a tiny fraction of the number of stars in a galaxy like the Milky Way. Dwarf galaxies often show a hazy structure, an ill-defined shape, and an appearance somewhat akin to a swarm or cloud of stars — and UGC 685 is no exception to this. Classified as an SAm galaxy — a type of unbarred spiral galaxy — it is located about 15 million light-years from Earth.

These data were gathered under the NASA/ESA Hubble Space Telescope’s LEGUS (Legacy ExtraGalactic UV Survey) Program, the sharpest and most comprehensive ultraviolet survey of star-forming galaxies in the nearby Universe.

LEGUS is imaging 50 spiral and dwarf galaxies in our cosmic neighbourhood in multiple colours using Hubble’s Wide Field Camera 3 (WFC3). The survey is picking apart the structures of these galaxies and resolving their constituent stars, clusters, groups, and other stellar associations. Star formation plays a huge role in shaping its host galaxy; by exploring these targets in detail via both new observations and archival Hubble data, LEGUS will shed light on how stars form and cluster together, how these clusters evolve, how a star’s formation affects its surroundings, and how stars explode at the end of their lives.

starsurfer wrote: ↑Tue Sep 03, 2019 2:26 pm P Cygni, PN G75.5+1.7 and Abell 69
http://www.capella-observatory.com/Imag ... ndPCyg.htm
Copyright: Josef Pöpsel, Max Pöpsel, Stefan Binnewies and Frank Sackenheim
PCyg.jpg

Paranal Residencia ~ Image Credit: ESO/Petr Horálek

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This beautiful image features the Milky Way rising over the Residencia at ESO’s Paranal Observatory, which can be seen atop a mountain in the distance. The Residencia is ESO’s private hotel for staff at Paranal, a home away from home for the astronomers, engineers, technicians, and other visitors to the site. Known as an “oasis for astronomers”, the building includes a restaurant, music room, library, swimming pool, and even a sauna to help astronomers to relax between and after their shifts. It was even featured in the James Bond film “Quantum of Solace” (2008).

This photograph was taken by ESO Photo Ambassador Petr Horálek, and is a great demonstration of just how artificial light can pollute its environment — the brightness of the Residencia lights seems almost blinding compared to the stars. Artificial light scatters off the particles in our atmosphere and can drown out the night sky. Preserving the dark skies around Paranal is of the utmost importance to ESO — the darkness surrounding the observatory allows astronomers to obtain excellent data. The preservation of dark skies is critical to the sensitivity and clarity of science observations. The non-celestial lights in this image are relatively few — a stark contrast to the streetlight-studded roads and illuminated cities you may be used to.

UGC 695 ~ Image Credit: ESA/Hubble & NASA, D. Calzetti

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This image, taken with the NASA/ESA Hubble Space Telescope, focuses on an object named UGC 695, which is located 30 million light-years away within the constellation Cetus (The Sea Monster), also known as The Whale.

UGC 695 is a low-surface-brightness (LSB) galaxy. These galaxies are so faint that their brightness is less than the background brightness of Earth’s atmosphere, which makes them tricky to observe. This low brightness is the result of the relatively small number of stars within them — most of the baryonic matter in these galaxies exists in the form of huge clouds of gas and dust. The stars are also distributed over a relatively large area.

LSB galaxies, like dwarf galaxies, have a high fraction of dark matter relative to the number of stars they contain. Astronomers still debate about how LSB galaxies formed in the first place.

Susanna Kohler wrote:

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How do molecules form in the hostile environments of the circumstellar and interstellar medium? Laboratory experiments are helping us to better understand this process! The image above (click for the full view) shows a high-resolution electron microscopy image of the complex surfaces of silicate grains, representative of dust grains found in the space around and between stars. In a new study led by Alexey Potapov (Max Planck Institute for Astronomy, Germany), scientists deposited thin layers of carbon dioxide and ammonia ices on nanometer-sized silicate and carbon grains and explored the subsequent chemical reactions under conditions similar to those of the interstellar medium. In the team’s experiments, the reactions that form complex organic molecules happened three times as fast in the ice on the surface of dust grains as they did in the ice alone. This catalytic effect of dust surfaces is an important piece in the puzzle of how complex molecules — and ultimately, life — formed in our universe. You can read the full article below to find out more!

• Astrophysical Journal Letters 878(1):L20 (2019 Jun 10) DOI: 10.3847/2041-8213/ab2538
• arXiv.org > astro-ph > arXiv:1905.13471 > 31 May 2019

starsurfer wrote: ↑Wed Sep 11, 2019 12:46 pm Sh2-96
http://outters.fr/wp/?p=8274
Copyright: Nicolas Outters
Sh2-96.jpg

bystander wrote: ↑Mon Sep 02, 2019 3:01 pm Caught in the Act
ESO Picture of the Week | 2019 Sep 02

Credit: ESO/R Leaman/D Gadotti/K Sandstrom/D Calzetti

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NGC 3351, also known as Messier 95, was first discovered in 1781 by Pierre Méchain, a French astronomer and surveyor who worked alongside Charles Messier. NGC 3351 is a type of galaxy known as a barred spiral galaxy and it is located in the constellation of Leo (The Lion).

New observations of this object have shown stellar feedback in action. Stellar feedback is the process of redistributing energy into the interstellar medium (the space in between the stars) within star-forming galaxies. In this particular galaxy, star formation is occurring in the ring surrounding the galaxy nucleus at such a violent rate that massive bubbles of hot gas can actually be seen being ejected. This ejected gas can then contribute (both positively and negatively) to ongoing star formation within the galaxy.

The data for this observation were taken with ALMA, the NASA/ESA Hubble Space Telescope and the Very Large Telescope, showing once again that scientific collaboration across multiple facilities can produce some wonderful results.

Ann wrote: ↑Wed Sep 11, 2019 1:23 pm

starsurfer wrote: ↑Wed Sep 11, 2019 12:46 pm Sh2-96
http://outters.fr/wp/?p=8274
Copyright: Nicolas Outters
Sh2-96.jpg

Interesting! This kind of nebulosity really, really looks as if it was caused by a single energetic star or possibly a supernova explosion. At least the magenta filament in the lower part of the picture looks like it could be a remnant of a supernova explosion, but the red streamers don't look like that. The blue star a center right looks like it could be just the kind of energizing source that we are looking for, but my software says that this star (HD 183300) belongs to unimpressive spectral class A.

Fascinating image anyway!

Ann