Starship Asterisk*

starsurfer wrote:NGC 3310
https://www.aao.gov.au/news-media/news/cosmic-poll-2015
Copyright: AAO ITSO office, Gemini Observatory/AURA and T.A. Rector (University of Alaska Anchorage)

ngc3310_gemini.jpg

[img3="Credit: ESA/Hubble & NASA
Acknowledgement: Judy Schmidt"]http://cdn.spacetelescope.org/archives/ ... w1606a.jpg[/img3]

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In this cosmic snapshot, the spectacularly symmetrical wings of Hen 2-437 show up in a magnificent icy blue hue. Hen 2-437 is a planetary nebula, one of around 3000 such objects known to reside within the Milky Way.

Located within the faint northern constellation of Vulpecula (The Fox), Hen 2-437 was first identified in 1946 by Rudolph Minkowski, who later also discovered the famous and equally beautiful M2-9 (otherwise known as the Twin Jet Nebula). Hen 2-437 was added to a catalogue of planetary nebula over two decades later by astronomer and NASA astronaut Karl Gordon Henize.

Planetary nebulae such as Hen 2-437 form when an aging low-mass star — such as the Sun — reaches the final stages of life. The star swells to become a red giant, before casting off its gaseous outer layers into space. The star itself then slowly shrinks to form a white dwarf, while the expelled gas is slowly compressed and pushed outwards by stellar winds. As shown by its remarkably beautiful appearance, Hen 2-437 is a bipolar nebula — the material ejected by the dying star has streamed out into space to create the two icy blue lobes pictured here.

Ann wrote:

starsurfer wrote:NGC 3310
https://www.aao.gov.au/news-media/news/cosmic-poll-2015
Copyright: AAO ITSO office, Gemini Observatory/AURA and T.A. Rector (University of Alaska Anchorage)

ngc3310_gemini.jpg

The Gemini Observatory/AURA and T.A. Rector image of NGC 3310 has apparently won a poll.

For myself, I can only notice that this is the second prestigious telescope non-RGB portrait of NGC 3310. The first one was the Hubble version. When it comes to the Hubble image, I think the aim of that was to figure out the exact age of the overwhelmingly rich populations of OB stars in NGC 3310. Fair enough.

But what is the aim of the Gemini image? The arms of NGC 3310 are pink in the image, which is correct. But why are the inner arms yellow? They are full of OB stars. And why are the outermost parts of the galaxy the bluest? These parts are likely to contain no O stars and few B stars, so they are certainly yellower than the inner parts.

Click to view full size image

NGC 3310. Photo: Adam Block.

It saddens me to see color being used so carelessly as in the Gemini image for no reason, and I can't recommend Adam Block's image of the same galaxy highly enough. Unfortunately, Adam has access to a much smaller telescope than Gemini and can't go as deep. That said, his use of color is absolutely splendid, and his portrayal of the outer parts of NGC 3310 is stunning.

Okay, there is no poll, but if there had been - surely you would have voted for Adam's picture of NGC 3310?

Ann

[img3="Young star HD 97300 lights up reflection nebula IC 2631 (Credit: ESO)"]http://cdn.eso.org/images/screen/eso1605a.jpg[/img3][hr][/hr]

A newly formed star lights up the surrounding cosmic clouds in this new image from ESO’s La Silla Observatory in Chile. Dust particles in the vast clouds that surround the star HD 97300 diffuse its light, like a car headlight in enveloping fog, and create the reflection nebula IC 2631. Although HD 97300 is in the spotlight for now, the very dust that makes it so hard to miss heralds the birth of additional, potentially scene-stealing, future stars.

The glowing region in this new image from the MPG/ESO 2.2-metre telescope is a reflection nebula known as IC 2631. These objects are clouds of cosmic dust that reflect light from a nearby star into space, creating a stunning light show like the one captured here. IC 2631 is the brightest nebula in the Chamaeleon Complex, a large region of gas and dust clouds that harbours numerous newborn and still-forming stars. The complex lies about 500 light-years away in the southern constellation of Chamaeleon.

IC 2631 is illuminated by the star HD 97300, one of the youngest — as well as most massive and brightest — stars in its neighbourhood. This region is full of star-making material, which is made evident by the presence of dark nebulae noticeable above and below IC 2631 in this picture. Dark nebulae are so dense with gas and dust that they prevent the passage of background starlight.

Despite its dominating presence, the heft of HD 97300 should be kept in perspective. It is a T Tauri star, the youngest visible stage for relatively small stars. As these stars mature and reach adulthood they will lose mass and shrink. But during the T Tauri phase these stars have not yet contracted to the more modest size that they will maintain for billions of years as main sequence stars. ...

[img3="Credit: NASA/ESA/Hubble"]http://cdn.spacetelescope.org/archives/ ... c1602a.jpg[/img3][hr][/hr]

The placid appearance of NGC 4889 can fool the unsuspecting observer. But the elliptical galaxy, pictured in this new image from the NASA/ESA Hubble Space Telescope, harbours a dark secret. At its heart lurks one of the most massive black holes ever discovered.

Located about 300 million light-years away in the Coma Cluster, the giant elliptical galaxy NGC 4889, the brightest and largest galaxy in this image, is home to a record-breaking supermassive black hole. Twenty-one billion times the mass of the Sun, this black hole has an event horizon — the surface at which even light cannot escape its gravitational grasp — with a diameter of approximately 130 billion kilometres. This is about 15 times the diameter of Neptune’s orbit from the Sun. By comparison, the supermassive black hole at the centre of our galaxy, the Milky Way, is believed to have a mass about four million times that of the Sun and an event horizon just one fifth the orbit of Mercury.

But the time when NGC 4889’s black hole was swallowing stars and devouring dust is past. Astronomers believe that the gigantic black hole has stopped feeding, and is currently resting after feasting on NGC 4889’s cosmic cuisine. The environment within the galaxy is now so peaceful that stars are forming from its remaining gas and orbiting undisturbed around the black hole. ...

[img3="Credit: Yuri Beletsky (LCO)/ESO"]http://cdn.eso.org/images/screen/potw1607a.jpg[/img3][hr][/hr]

This striking photograph from Yuri Beletsky captures many wonders — both terrestrial and astronomical — across an incredible distance scale.

In the immediate foreground looms ESO’s VISTA survey telescope. This 4.1-metre telescope scans the skies in infrared light, picking out astronomical objects of interest so that they can be studied by the four 8.2-metre Unit Telescopes of ESO’s Very Large Telescope (VLT) facility. This facility can be seen on the mountaintop to VISTA’s right, about a kilometre up the road.

In the sky above VISTA a luminous and dark-ribboned band runs from lower left to top right. This is the disc of the Milky Way, seen edge-on and looking inward toward the galactic core. Although we cannot see all the way to the core with our unaided eyes, we have gauged its distance as about 30 000 light-years from us. That distance works out as about 280 quadrillion kilometres, or 280 000 000 000 000 000 trips up the road from VISTA to the VLT!

The glowing blob seen here almost directly overhead of the VLT is the Large Magellanic Cloud (LMC), a dwarf galaxy that neighbours the Milky Way. It is about 160 000 light-years away. Below and slightly to the left of the LMC is another diffuse brightness in the sky, the Small Magellanic Cloud (SMC). This galaxy is nearly 200 000 light-years away meaning that, walking at five kilometres an hour, the journey to the SMC would take more than 43 trillion years.

[img3="Credit: ESA/Hubble & NASA; Acknowledgement: Judy Schmidt"]http://cdn.spacetelescope.org/archives/ ... w1607a.jpg[/img3][hr][/hr]

Surrounded by an envelope of dust, the subject of this NASA/ESA Hubble Space Telescope image is a young pre-main-sequence star known as HBC 1. The star is in an immature and adolescent phase of life, hence its classification — most of a Sun-like star’s life is spent in a stage comparable to human adulthood dubbed the main sequence.

In this view, HBC 1 illuminates a wispy reflection nebula known as IRAS 00044+6521. Formed from clouds of interstellar dust, reflection nebulae do not emit any visible light of their own and instead — like fog encompassing a lamppost — shine via the light from the stars embedded within. Though nearby stars cannot ionise the nebula’s non-gaseous contents, as with brighter emission nebulae, scattered starlight can make the dust visible.

What makes this seemingly ordinary reflection nebula more interesting are three nearby Herbig–Haro objects known as HH 943, HH 943B and HH 943A — which are not visible in this image — located within IRAS 00044+6521 itself. Herbig–Haro objects are small patches of dust, hydrogen, helium and other gases that form when narrow jets of gas ejected by young stars such as HBC 1 collide with clouds of gas and dust. Lasting just a few thousand years, these objects rapidly move away from their parent star before dissipating into space.