Hubble’s Portrait of Star’s Gaseous Glow


Hubble’s Portrait of Star’s Gaseous Glow

NGC 2022 as seen by Hubble

Although it looks more like an entity seen through a microscope than a telescope, this rounded object, named NGC 2022, is certainly not algae or tiny, blobby jellyfish. Instead, it is a vast orb of gas in space, cast off by an aging star. The star is visible in the orb’s center, shining through the gases it formerly held onto for most of its stellar life.

When stars like the Sun grow advanced in age, they expand and glow red. These so-called red giants then begin to lose their outer layers of material into space. More than half of such a star’s mass can be shed in this manner, forming a shell of surrounding gas. At the same time, the star’s core shrinks and grows hotter, emitting ultraviolet light that causes the expelled gases to glow.

This type of object is called, somewhat confusingly, a planetary nebula, though it has nothing to do with planets. The name derives from the rounded, planet-like appearance of these objects in early telescopes.

NGC 2022 is located in the constellation of Orion (the Hunter).

Text credit: ESA (European Space Agency)
Image credit: ESA/Hubble & NASA, R. Wade

Last Updated: Aug. 16, 2019

Editor: Rob Garner

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Geoff Sherrington
August 18, 2019 2:58 am

Many hours could be pleasantly spent in a library of Hubble images, for the artistic value, let alone the science. As we know it. Geoff S

August 18, 2019 4:02 am

This is of course an illustration of the very serious global warming that we are likely to encounter in a few billion years. The Sun will swell up and swallow us along with Mercury and Venus (and just possibly Mars?). It will be as much our fault as this present episode of AGW.

Hopefully by then we will have spread ourselves far and wide in the Universe so life will carry on. It’s reassuring to see Musk and others making the first steps in this direction. I would think that if we can survive the next couple of generations our survival as a species is guaranteed.

Kevin kilty
Reply to  Alastair Brickell
August 18, 2019 8:25 am

Indeed, the thought of Musk heading off into the universe is lifting.

GW Smith
Reply to  Alastair Brickell
August 18, 2019 1:09 pm

Of course, this assumes the standard model is correct. And, if it’s realized that the sun is not a nuclear furnace, but a continuously discharging electromagnetic plasmoid, then all this is mute and we can continue living here. But we still support space exploration, of course.

Dan Cody
August 18, 2019 4:11 am

Beautiful.It almost looks like a portal to another dimension.

Reply to  Dan Cody
August 18, 2019 1:17 pm

Dan Cody
August 18, 2019 at 4:11 am

That’s no joke Dan!

August 18, 2019 4:15 am

Even the stars are mortal. They are born in star nurseries of gas and when they leave, they have a trail of gases that look distinctly like an umbilical. They age, have life spans and reach old age and die, leaving behind trails of gases.

Nicely done.

John Tillman
Reply to  Sara
August 18, 2019 11:06 am

The longest-lived, cool red dwarf stars are practically immortal, lasting trillions of years. Should the universe exist that long, then they will finally use up all their hydrogen and die. But the end of the universe might come before then, so they would die only with it, possibly in a Big Crunch, should it contain enough mass for that to be its gravitational fate.

John Tillman
Reply to  John Tillman
August 18, 2019 12:27 pm

“Red dwarf stars make up the largest population of stars in the galaxy, but they hide in the shadows, too dim to be seen with the naked eye from Earth. Their limited radiance helps to extend their lifetimes, which are far greater than that of the sun.

“Scientists think that 20 out of the 30 stars near Earth are red dwarfs. The closest star to the sun, Proxima Centauri, is a red dwarf.

“The term “red dwarf” does not refer to a single kind of star. It is frequently applied to the coolest objects, including K and M dwarfs — which are true stars — and brown dwarfs, often referred to as “failed stars” because they do not sustain hydrogen fusion in their cores.”


Joel O'Bryan
Reply to  John Tillman
August 19, 2019 9:39 am

Proxima Centauri (PC) is also a flare star. It has noted to occasionally have very vigorous flaring activity that likely keeps any rocky exoplanets it may have completely sterilized with strong UV and particle radiation bombardment.
The flaring nature is because PC has no radiative zone due to its small size. Its convective zone is directly in contact with the very hot core boundary, meaning it is likely a chaotic roiling interface, unlike our Sun’s tachocline orderly interface between the radiative zone and the convective zone.

Prediction: Mid-June 2020 (14-18 June 2020) Proxima Centauri will have a major outbreak of flaring activity as a light show for Earth-bound astronomers.

August 18, 2019 4:44 am

The visible planets are relatively close to us and thus have enough angular diameter that they don’t twinkle. The stars are so far away that they act like point sources and disturbances in the atmosphere make them twinkle.

The magnification of the Hubble is only on the order of 1000. link So why do the stars in the image above seem to have such large angular diameters?

Reply to  commieBob
August 18, 2019 5:10 am

The pictures were time lapsed. Stars twinkle to the eye because the eye is not lapsed.

Reply to  Marv
August 18, 2019 7:44 am

Not only that, but Hubble is not compromised by having to look through a lot of atmosphere. I would guess that stars would not twinkle even on short exposures with Hubble….?

Reply to  commieBob
August 18, 2019 5:40 am

The resolution of the Hubble longer term exposures is limited by the stability of the pointing mechanism.
There are gyroscopes on board to get the telescope pointing the right way, but the process is never perfect.
Also, the image we see is limited by the sensor on the telescope. At a minimum, a bright star will illuminate one pixel on the sensor, which is a 0.64 million pixel CCD.

Crispin in Waterloo
Reply to  etudiant
August 18, 2019 10:27 am

0.64 megapixel CCD?

That seems unlikely.

Without getting into the optical zoom details and the assemblage of multi-frame into a single picture. The Hubble uses 4x640k arrays at a time (2.4 MPix) and multiple exposures to assemble a large high resolution image.

There are producers of CCD’s for telescope (and surveillance) optics one of which is here in Waterloo, that made 104 megapixel arrays long ago. A typical installation also used 4 of them. These days they are certainly 0.8 gigapixels per set.

Reply to  commieBob
August 18, 2019 6:56 am

commieBob, good question. I was wondering that myself. The two answers you got so far so not seem satisfactory. So I looked again. The image is much higher res, click to embiggen or open in a new tab. Now you can see the classic crosshairs pattern of CCD blooming. In this case, the pixels illuminated by the star get saturated and dump charge into the next pixel in line. The charge dump typically is very strongly oriented along one axis or the other. But here it seems both horizontal and vertical are more or less symmetrical. Then, if you look at the edges, you see all the radial lines, all faint but in all directions. So it looks like the whole star size is due to blooming. I know this is not a very good explanation but it is all I have got.
Pixel size can be estimated from the width of the lines, very small compared to the star.
Pointing error can be “worst case” estimated from the smallest star. It seems the error cannot be larger than that.
Now look at that star at 45 degrees from vertical, and on the edge of the outer blue cloud. It has a strong orange halo, just like the main star. So this is a camera artifact of some sort. Blooming or something else?
I really do not know.

Reply to  TonyL
August 18, 2019 7:33 am

Thanks for pointing me in the right direction. blooming

Reply to  TonyL
August 18, 2019 7:50 am

Stars twinkle to the naked eye because the coherence length of the atmosphere in the visible wavelengths is about 30 cm. Each little glob of 30 cm air acts like a little lens, diffracting the light, sometimes in your eye and sometimes just out of the eye aperture. Planets have a larger angular subtense so they are less likely to twinkle. Real world example of quantum mechanics.
Hubble pointing is accomplished through a stellar inertial guidance and pointing system using gyros and star trackers for pointing knowledge and wheels to precisely point to less than sub-microradians for thousands of seconds or more. The system measures the position of the primary mirror, unfortunately the movement of the secondary mirror dominates image jitter. Any movement by the secondary mirror is 12 times more sensitive than motion of the primary. Therefore there is always some blurring of point sources (distant stars).
The crosshair pattern on stars is diffracted light caused by the secondary mirror spider assembly. Each telescope using an on-axis secondary mirror has some diffraction pattern which can be recognized. CCDs cause other artifacts in the image depending on the pixel sampling of the diffraction limited blur as well as readout effects. A well calibrated system can eliminate most of this in processing.

Reply to  TonyL
August 18, 2019 8:02 am

I think two other things *might* also be at play here. I’m not sure of the Hubble’s internal geometry but sometimes reflector telescopes with secondary mirrors can have artifacts caused by the geomery of the mirror supports. That might have something to do with the “crosshair” artifacts…or not.

In addition, the (probably diffraction) limited resolution of the telescope may create an apparent size to point objects that depends on brightness.

These are both guesses as I’m not an optics expert…perhaps we have one here who could chime in…?

Reply to  commieBob
August 18, 2019 2:28 pm

No lens is absolutely perfect – there is always some scattering. As noted below, Hubble images are time exposures, causing more scatter to appear.

J Mac
August 18, 2019 9:10 am

Like a fiddler on the cosmic roof top, Hubble’s lofty perspective provides panoramic poetry:
Sunrise. Sunset. Swiftly, swiftly fly the years….

August 18, 2019 9:19 am

Here’s an interesting picture taken by Hubble …

There are a lot of crosshair patterns associated with stars but at the same time there appears to be some fine resolution with the dust. It seems to me that an overload of photons coming from the stars interferes with the star’s resolution while the scarcity of photons from the dust allows for some very fine resolution.

Reply to  Marv
August 18, 2019 11:21 am

Perhaps this picture will offer up a better look …

comment image

William Astley
August 18, 2019 9:20 am

Astronomy is smoking hot as a field. There are a couple of new paradox observations found almost year.

This is the unexpected observational discovery this year of a large number of high redshift galaxies which were not seen in previous surveys due to telescope limitation.

These newly discovered high redshift mature galaxies are ten to hundred times more in number per region of space than the old semi-analytical astronomical simulation models predicted.

In fact, the newest more accurate astronomical modelling, hydrodynamic simulation does not form any mature large galaxies at the high redshift that the newly found galaxies are at.

This is the discovery that there is too much high redshift radiation which in turn would require too many high redshift galaxies.

The problem of too many high redshift galaxies is theoretically if we live in a big bang universe the high number of high redshift galaxies would change the amount of metals in current galaxies which is not observed.

(Note the 2019 discovery of ten to hundred times more high redshift galaxies would make this problem ten to hundred times more paradoxical.)

Trouble at first Light

But rather than helping to decipher the epoch of cosmic first light, such observations have in fact created another puzzle. Simply stated, the dawn of galaxies seems to be too brilliant: the excess signal outshines the cumulative emission from all galaxies between Earth and the extremely distant first stars.

If primordial sources are to account for all of this infrared radiation, current models of star formation in the young Universe look distinctly shaky.

Too many massive stars ending their brief lives in a giant thermonuclear explosion would, for instance, eject large amounts of heavy elements such as carbon and oxygen into space, polluting the cosmos very early on and altering for ever the composition of the raw material available for second-generation stars. But if the first-generation stars were to collapse to massive black holes instead, gas accretion onto such black holes would produce large amounts of X-rays. Both variants seem to be in conflict with current observations8

Reply to  William Astley
August 18, 2019 5:37 pm

Maybe, now imagine an expanding vacuum.

Joel O'Bryan
August 19, 2019 9:30 am

You can actually make-out the two polar jets that are driving the elliptical shaping of the plasma bubble along its major axis. Radio telescopes can examine the Doppler shifting of the jets’ radio signals to determine the material outward speed and relative angles to Earth. All of which help refine models of stellar evolution and death.

Reply to  Joel O'Bryan
August 20, 2019 6:55 am

That’s what I recall — close-ups of certain areas on the Pillars show some newly-forming stars embedded in the dust producing jets! Quite amazing.

Johann Wundersamer
August 21, 2019 1:41 am

The Hubble Telescope is truly a stunning gift of science.

Despite the difficult birth and despite the latest observation instruments with wider spectrum and higher resolution, it is still a fantastic imager and thus knowledge mediator.

Johann Wundersamer
August 21, 2019 2:01 am

In curious anticipation of “representations” of a neutron star.

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