A ghostly green bubble: VLT snaps a planetary nebula

A ghostly green bubble: VLT snaps a planetary nebula
This intriguing picture from ESO’s Very Large Telescope shows the glowing green planetary nebula IC 1295 surrounding a dim and dying star. It is located about 3300 light-years away in the constellation of Scutum (The Shield). This is the most detailed picture of this object ever taken. Credit: ESO

(Phys.org) —This intriguing new picture from ESO's Very Large Telescope shows the glowing green planetary nebula IC 1295 surrounding a dim and dying star located about 3300 light-years away in the constellation of Scutum (The Shield). This is the most detailed picture of this object ever taken.

Stars the size of the Sun end their lives as tiny and faint white dwarf stars. But as they make the final transition into retirement their atmospheres are blown away into space. For a few tens of thousands of years they are surrounded by the spectacular and colourful glowing clouds of ionised gas known as planetary nebulae.

This new image from the shows the IC 1295, which lies in the of Scutum (The Shield). It has the unusual feature of being surrounded by multiple shells that make it resemble a micro-organism seen under a microscope, with many layers corresponding to the membranes of a cell.

These bubbles are made out of gas that used to be the star's atmosphere. This gas has been expelled by unstable fusion reactions in the star's core that generated sudden releases of energy, like huge thermonuclear belches. The gas is bathed in strong from the aging star, which makes the gas glow. Different glow with different colours and the ghostly green shade that is prominent in IC 1295 comes from ionised oxygen.

At the centre of the image, you can see the burnt-out remnant of the star's core as a bright blue-white spot at the heart of the nebula. The will become a very faint white dwarf and slowly cool down over many billions of years.

Stars with masses like the Sun and up to eight times that of the Sun, will form planetary nebulae as they enter the of their existence. The Sun is 4.6 billion years old and it will likely live another four billion years.

Despite the name, planetary nebulae have nothing to do with planets. This descriptive term was applied to some early discoveries because of the visual similarity of these unusual objects to the outer planets Uranus and Neptune, when viewed through early telescopes, and it has been catchy enough to survive. These objects were shown to be glowing gas by early spectroscopic observations in the nineteenth century.

This image was captured by ESO's Very Large Telescope, located on Cerro Paranal in the Atacama Desert of northern Chile, using the FORS instrument (FOcal Reducer Spectrograph). Exposures taken through three different filters that passed blue light (coloured blue), visible light (coloured green), and red light (coloured red) have been combined to make this picture.


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Apr 10, 2013
Despite the name, planetary nebulae have nothing to do with planets.
If Pluto can be demoted from being a "planet", why can't these guys figure out another name for these things? like "stellar nebula"? or ""final phase of [a star's] existence" cloud""?

Apr 10, 2013
Despite the name, planetary nebulae have nothing to do with planets.
If Pluto can be demoted from being a "planet", why can't these guys figure out another name for these things? like "stellar nebula"? or ""final phase of [a star's] existence" cloud""?


I'm partial to "supernovae remnant", but that's just me. I suppose the main reason is that it is an historical comfort thing.

But even though they aren't formed from "planets", they will someday be used in the formation of planets.

The term "stellar nebulae" would probably problematic because that was once the term used for what we now call galaxies. And it's still found in the literature into the 1930's and 40's.

Apr 10, 2013
If Pluto can be demoted from being a "planet", why can't these guys figure out another name for these things? like "stellar nebula"? or ""final phase of [a star's] existence" cloud""?


I'm partial to "supernovae remnant", but that's just me.


It's a good name where appropriate but these nebula don't result from supernovae but from what is essentially just a very high rate stellar wind. "Windy nebulae" doesn't have quite the same glamour ;-)

Apr 10, 2013
Why is there so little evidence of gravitational perturbations from other stars on the cloud? There is only one minor imperfection in the cloud, on the right hand side, and other than that it appears nearly perfectly symmetrical.

Based on the purported distance to the cloud, the width ought to be quite very huge indeed, particularly given the spatial relationship of the background stars.

That is to say, there should be many stars inside the cloud and many stars just outside the cloud, which should have gobbeled wholes in the gas as it has expanded, at the very least through head-on collisions.

Why are they not evident at all?!

Apr 11, 2013
I think we should call it a "Green Giant".

Apr 11, 2013
Why is there so little evidence of gravitational perturbations from other stars on the cloud? There is only one minor imperfection in the cloud, on the right hand side, and other than that it appears nearly perfectly symmetrical.

Based on the purported distance to the cloud, the width ought to be quite very huge indeed, particularly given the spatial relationship of the background stars.


It is only about 0.8 light years in radius. Our nearest neighbour is 4 light years away so there are unlikely to be any close to it.

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