Stellar extremophiles

Nov 08, 2011 By Dr. Tony Phillips
Stellar extremophiles
This composite (radio+UV) image shows long octopus-like arms of star formation stretching far away from the main disk of spiral galaxy M83. Credit: NASA/JPL-Caltech/VLA/MPIA

Back in the 1970s, biologists were amazed to discover a form of life they never expected.  Tiny microorganisms with ancient DNA were living in the hot springs of Yellowstone National Park.  Instead of dissolving in the boiling waters, the microbes were thriving, ringing the springs with vibrant color.

Scientists coined the term extremophile, which means "extreme-loving", to describe the creatures--and the hunt was on for more.  Soon, extremophiles were found living in deep Antarctic ice, the cores of nuclear reactors, and other unexpected places.  Biology hasn't been the same since.

Could astronomy be on the verge of a similar transformation?

Researchers using a NASA space telescope named GALEX have discovered a new kind of extremophile: extreme-loving .

"We’re finding stars in extreme galactic environments where star formation isn't supposed to happen," explains GALEX project scientist Susan Neff of the Goddard Space Flight Center. “This is a very surprising development."

This video is not supported by your browser at this time.
This composite (radio+UV) image shows long octopus-like arms of star formation stretching far away from the main disk of spiral galaxy M83.

GALEX, which stands for “Galaxy Evolution Explorer,” is an ultraviolet space telescope with a special ability: It is super-sensitive to the kind of UV rays emitted by the youngest stars.  This means the observatory can detect stars being born at very great distances from Earth, more than halfway across the Universe.  The observatory was launched in 2003 on a mission to study how galaxies change and evolve as new stars coalesce inside them.

GALEX accomplished that mission—and more.

"In some GALEX images, we see stars forming outside of galaxiesin places where we thought the gas density would be too low for star birth to occur," says GALEX team member Don Neil of Caltech. 

Stars are born when interstellar clouds of gas collapse and contract under the pull of their own gravity.  If a cloud gets dense and hot enough as it collapses, nuclear fusion will kick in and—voila!--a star is born. 

The spiral arms of the Milky Way are a "goldilocks zone" for this process.  "Here in the Milky Way we have plenty of gas.  It’s a cozy place for stars to form," says Neil.

But when GALEX looks at other more distant spiral galaxies, it sees stars forming far outside the gassy spiral disk.  

"I was dumbfounded," he says. "These stars are truly 'living on the edge. '"

Spirals aren’t the only galaxies with stellar extremophiles. The observatory has also found stars being born

--in elliptical and irregular galaxies thought to be gas-poor (e.g., 1, 2)

--in the gaseous debris of colliding galaxies (1, 2)

--in vast "comet-like" tails that trail behind some fast-moving (1, 2)

--in cold primordial gas clouds, which are small and barely massive enough to hang together

So much for the Goldilocks Zone.  According to GALEX, stellar extremophiles populate just about every nook and cranny of the cosmos where a wisp of gas can get together to make a new sun.

“This could be telling us something profound about the star-forming process,” says Neff.  “There could be ways to make stars in extreme environments that we haven’t even thought of yet.”

Will extremophiles transform astronomy as they did biology?  It’s too soon to say, insist the researchers. But GALEX has definitely given them something to think about.

Explore further: Mysterious molecules in space

Related Stories

A star with spiral arms

Nov 01, 2011

For more than four hundred years, astronomers have used telescopes to study the great variety of stars in our galaxy. Millions of distant suns have been catalogued. There are dwarf stars, giant stars, dead ...

Spitzer photo atlas of galaxy 'train wrecks'

May 25, 2011

(PhysOrg.com) -- Five billion years from now, our Milky Way Galaxy will collide with the Andromeda Galaxy. This will mark a moment of both destruction and creation. The galaxies will lose their separate identities ...

New theory of evolution for spiral galaxy arms

Apr 21, 2011

(PhysOrg.com) -- A study of spiral patterns found in galaxies like our Milky Way could overturn the theory of how the spiral arm features form and evolve. The results are being presented by postgraduate student, ...

New stars from old gas surprise astronomers

Feb 18, 2009

(PhysOrg.com) -- Evidence of star birth within a cloud of primordial gas has given astronomers a glimpse of a previously unknown mode of galaxy formation. The cloud, known as the Leo Ring, appears to lack ...

'Dead' galaxies are not so dead after all

May 30, 2011

(PhysOrg.com) -- University of Michigan astronomers examined old galaxies and were surprised to discover that they are still making new stars. The results provide insights into how galaxies evolve with time.

Recommended for you

Astronomers measure weight of galaxies, expansion of universe

5 hours ago

Astronomers at the University of British Columbia have collaborated with international researchers to calculate the precise mass of the Milky Way and Andromeda galaxies, dispelling the notion that the two galaxies have similar ...

Mysterious molecules in space

16 hours ago

Over the vast, empty reaches of interstellar space, countless small molecules tumble quietly though the cold vacuum. Forged in the fusion furnaces of ancient stars and ejected into space when those stars ...

Comet Jacques makes a 'questionable' appearance

Jul 28, 2014

What an awesome photo! Italian amateur astronomer Rolando Ligustri nailed it earlier today using a remote telescope in New Mexico and wide-field 4-inch (106 mm) refractor. Currently the brightest comet in ...

Image: Our flocculent neighbour, the spiral galaxy M33

Jul 28, 2014

The spiral galaxy M33, also known as the Triangulum Galaxy, is one of our closest cosmic neighbours, just three million light-years away. Home to some forty billion stars, it is the third largest in the ...

Image: Chandra's view of the Tycho Supernova remnant

Jul 25, 2014

More than four centuries after Danish astronomer Tycho Brahe first observed the supernova that bears his name, the supernova remnant it created is now a bright source of X-rays. The supersonic expansion of ...

User comments : 16

Adjust slider to filter visible comments by rank

Display comments: newest first

dtyarbrough
1 / 5 (1) Nov 08, 2011
Not at all unusual if you understand the true nature of http://www.scribd...97/STARS .
yyz
1 / 5 (2) Nov 08, 2011
The title ought to be renamed "Galacic Extremophiles" in light of the subject matter(M 83). A fascinating, nearby massive stellar system.

A recent paper has been published outlining some of the peculiar features of this galaxy: http://arxiv.org/...50v1.pdf
Cynical1
5 / 5 (1) Nov 08, 2011
Here's my take - "Life" forms wherever it can...
Vendicar_Decarian
not rated yet Nov 08, 2011
I am not at all surprised by this. I have never understood why astronomers have presumed that intergalactic space was star free or nearly star free.

The star formation and galaxy formation process must be hightly inefficient and must leave considerable amounts of matter uncollected. Further galaxy mergers in simulations spew billions of stars into extra-galactic space.

yyz
not rated yet Nov 08, 2011
"I have never understood why astronomers have presumed that intergalactic space was star free or nearly star free."

"The star formation and galaxy formation process must be hightly inefficient and must leave considerable amounts of matter uncollected. Further galaxy mergers in simulations spew billions of stars into extra-galactic space."

The resulting multitudes of stars and gaseous nebulae would show up in the Lyman-alpha forests of the most distant quasars. As this is not observed, it is concluded that the universe is not densely filled with gas and stars between galaxies and galaxy clusters.

This hot intergalactic gas, heated by energetic radiation from the embedded populations of stars would also emit copiously (and isotropically) in the xray portion of the spectrum, and this again is not observed.
Cynical1
1 / 5 (1) Nov 08, 2011
Think I'm goin' with VD on this one...
that_guy
not rated yet Nov 08, 2011
I'm sure that there's a limit of how 'few' stars we can easily detect through the lyman alpha forest, due to the accuracy of our equipment and the signal being obscured by other signals or mistaken association with a known galaxy.

However, I think this case is probably more related to the plethora of minor satellite galaxies found around the milky way, and the relative lack of detection of these satellites around other major galaxies.

I think our understanding will evolve as our instruments and observations do - I bet this is just a piece of the puzzle understanding the local interactions of a galaxy.
TimESimmons
1 / 5 (1) Nov 08, 2011
we see stars forming outside of galaxies in places where we thought the gas density would be too low for star birth to occur
here's why:- http://www.presto...ndex.htm
yyz
not rated yet Nov 08, 2011
"I'm sure that there's a limit of how 'few' stars we can easily detect through the lyman alpha forest,"

Your overlooking the mulitudinous effects of myriads of stars that would present themselves in even the narrowest spectrographic slit, assuming stars are distributed isotropically in intergalactic space. The effect would be quite noticeable in the very noisy S/N ratio.
that_guy
5 / 5 (1) Nov 08, 2011
To clarify - I know evidence shows that there is likely not very many intergalactic stars - But there is a mathematical point where we cannot currently decipher or detect the signatures of stars below a certain density.

This is supported by the article, as the new instrument finds stars where they were not expected - meaning they were either attributed to be directly in the galaxy or not enough signal to detect at all, probably some variation of both:
"In some GALEX images, we see stars forming outside of galaxies in places where we thought the gas density would be too low for star birth to occur," says GALEX team member Don Neil of Caltech


Once again, I was just making a statement regarding the limits of our observations, but not the magnitude of the margin of error.

I would assume that it is small enough not to overturn any major conclusions, but just pointing out that there are probably many interesting but small details we have yet to see.
yyz
not rated yet Nov 08, 2011
Well, we are in agreement that starbirth can (and does) occur outside the "visible" portion of some galaxies (tidal dwarf galaxies are but one example). In the case of M 83, excess hydrogen exterior to the main body of the galaxy has been known for some time, as has the GALEX UV observations. Spitzer IR observations have also revealed a quantity of warm gas and starbirth outside the visible confines of M 83: http://arxiv.org/...32v3.pdf

A recent paper also uses HST observations to examine starbirth in the inner and outer regions of M 83: http://arxiv.org/...37v1.pdf

M 83 presents a unique, nearby specimen of a massive, isolated galaxy undergoing intense starbirth in its' inner regions, and an abundant supply of raw materiel and a stellar bar to help fuel the vigorous activity that we see.
Objectivist
not rated yet Nov 08, 2011
Here's my take - "Life" forms wherever it can...

Anything forms wherever it can. Elements, chemical compounds, life, societies, cities, planets, stars, galaxies. That's elementary. The question is: where can it form?
Cynical1
1 / 5 (1) Nov 09, 2011
Anything forms wherever it can. Elements, chemical compounds, life, societies, cities, planets, stars, galaxies. That's elementary. The question is: where can it form?

I know you actually meant - where CAN'T it form...:-)
I just happen to feel that if ANYthing self-assembles/evolves (utilizing the rudimentary elements in it's environment) into a (more complex than it's elements) "thing", it is alive.
Just my "theory"...
Objectivist
not rated yet Nov 09, 2011
No I meant what I wrote. We want to know where these locations are. So that we may look for them or even anticipate them.
Cynical1
not rated yet Nov 09, 2011
okay, I can see that. I just thought you were saying something to fact that it can & does form everywhere..
Osiris1
1 / 5 (1) Nov 09, 2011
How would you like to be the only kid on your block...I mean a sentient on a planet about a 'rogue' star. And then found out some wag in a system somewhere named your central star 'SarahPalinova'