ESO: A Fleeting Moment in Time (ESO 577-24)

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bystander
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ESO: A Fleeting Moment in Time (ESO 577-24)

Post by bystander » Tue Jan 22, 2019 7:09 pm

A Fleeting Moment in Time
ESO Photo Release | 2019 Jan 22

ESO’s Cosmic Gems Programme captures last breath of a dying star

The faint, ephemeral glow emanating from the planetary nebula ESO 577-24 persists for only a short time — around 10,000 years, a blink of an eye in astronomical terms. ESO’s Very Large Telescope captured this shell of glowing ionised gas — the last breath of the dying star whose simmering remains are visible at the heart of this image. As the gaseous shell of this planetary nebula expands and grows dimmer, it will slowly disappear from sight.

An evanescent shell of glowing gas spreading into space — the planetary nebula ESO 577-24 — dominates this image [1]. This planetary nebula is the remains of a dead giant star that has thrown off its outer layers, leaving behind a small, intensely hot dwarf star. This diminished remnant will gradually cool and fade, living out its days as the mere ghost of a once-vast red giant star.

Red giants are stars at the end of their lives that have exhausted the hydrogen fuel in their cores and begun to contract under the crushing grip of gravity. As a red giant shrinks, the immense pressure reignites the core of the star, causing it to throw its outer layers into the void as a powerful stellar wind. The dying star’s incandescent core emits ultraviolet radiation intense enough to ionise these ejected layers and cause them to shine. The result is what we see as a planetary nebula — a final, fleeting testament to an ancient star at the end of its life [2].

This dazzling planetary nebula was discovered as part of the National Geographic Society  — Palomar Observatory Sky Survey (NGS-POSS) in the 1950s, and was recorded in the Abell Catalogue of Planetary Nebulae in 1966 [3]. At around 1400 light years from Earth, the ghostly glow of ESO 577-24 is only visible through a powerful telescope. As the dwarf star cools, the nebula will continue to expand into space, slowly fading from view.

This image of ESO 577-24 was created as part of the ESO Cosmic Gems Programme, an initiative that produces images of interesting, intriguing, or visually attractive objects using ESO telescopes for the purposes of education and public outreach. The programme makes use of telescope time that cannot be used for scientific observations; nevertheless, the data collected are made available to astronomers through the ESO Science Archive.
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Ann
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Re: ESO: A Fleeting Moment in Time (ESO 577-24)

Post by Ann » Wed Jan 23, 2019 12:16 am

I find the colors really weird.

NGC 6781. Adam Block/NOAO/AURA/NSF
The picture at left shows the colors I expect from a planetary nebula. The inner parts are typically bluish or greenish from oxygen emission. The outer parts are typically red from ionized hydrogen. The central star is extremely hot and is therefore blue.

I realize that there are exceptions to this rule. Some planetary nebulas contain very little hydrogen and are almost all blue-green. Others appear to lack oxygen and are all red. And extremely young planetary nebulas have extremely hot central stars, which may be so hot that they emit very little light at optical wavelengths in the first place, and therefore they don't necessarily look blue.

The ESO planetary nebula has red inner parts and blue outer parts, and the central star is white. I don't understand how that can be possible.

Ann
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Re: ESO: A Fleeting Moment in Time (ESO 577-24)

Post by geckzilla » Wed Jan 23, 2019 4:21 am

Hi Ann, sometimes planetary nebulas get really messy. I've got an album full of them here:
https://www.flickr.com/photos/geckzilla ... 5424077786

They're not all using the same color scheme because I have no choice in the matter, but just try to pay attention to the shape rather than the colors and see how some of them do not seem to expand in such an orderly fashion. Some of them are barrels, some of them are spheres, or vaguely bubble shaped... some have rings, some are hourglasses... it goes on
Just call me "geck" because "zilla" is like a last name.

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Re: ESO: A Fleeting Moment in Time (ESO 577-24)

Post by bystander » Wed Jan 23, 2019 4:56 am

Ann wrote: Wed Jan 23, 2019 12:16 am I find the colors really weird.

The filters used and colors assigned can be found here.
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
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Re: ESO: A Fleeting Moment in Time (ESO 577-24)

Post by neufer » Fri Jan 25, 2019 4:10 am

Click to play embedded YouTube video.
Art Neuendorffer

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