The universe's most massive stars can form in near isolation, new study finds

Dec 21, 2010
Star 302, as viewed from the ground. Courtesy of Joel Lamb

(PhysOrg.com) -- New observations by University of Michigan astronomers add weight to the theory that the most massive stars in the universe could form essentially anywhere, including in near isolation; they don't need a large stellar cluster nursery.

This is the most detailed observational study to date of massive stars that appear (from the ground) to be alone. The scientists used the to zoom in on eight of these giants, which range from 20 to 150 times as massive as the Sun. The stars they looked at are in the Small Magellanic Cloud, a that's one of the Milky Way's nearest neighbors.

Their results, published in the Dec. 20 edition of the , show that five of the stars had no neighbors large enough for Hubble to discern. The remaining three appeared to be in tiny clusters of ten or fewer stars.

Doctoral student Joel Lamb and associate professor Sally Oey, both in the Department of Astronomy, explained the significance of their findings.

"My dad used to fish in a tiny pond on his grandma's farm," Lamb said. "One day he pulled out a giant largemouth bass. This was the biggest fish he's caught, and he's fished in a lot of big lakes. What we're looking at is analogous to this. We're asking: 'Can a small pond produce a giant fish? Does the size of the lake determine how big the fish is?' The lake in this case would be the cluster of stars.

"Our results show that you can, in fact, form big stars in small ponds."

The most massive stars direct the evolution of their galaxies. Their winds and radiation shape and promote the birth of new stars. Their violent supernovae explosions create all the heavy elements that are essential for life and the Earth. That's why astronomers want to understand how and where these form. There is currently a big debate about their origins, Oey said.

One theory is that the mass of a star depends on the size of the cluster in which it is born, and only a large star cluster could provide a dense enough source of gas and dust to bring about one of these . The opposing theory, and the one that this research supports, is that these monstrous stars can and do form more randomly across the universe—including in isolation and in very small clusters.

Star 302 as viewed through the Hubble Space Telescope, which can zoom in roughly 40 times closer. From the ground, everything within the circle appears to be one star. Courtesy of Joel Lamb

"Our findings don't support the scenario that the maximum mass of a star in a cluster has to correlate with the size of the cluster," Oey said.

The researchers acknowledge the possibility that all of the stars they studied might not still be located in the neighborhood they were born in. Two of the stars they examined are known to be runaways that have been kicked out of their birth clusters. But in several cases, the astronomers found wisps of leftover gas nearby, strengthening the possibility that the stars are still in the isolated places where they formed.

Explore further: Toothpaste fluorine formed in stars

More information: The title of the paper is "The Sparsest Clusters With O Stars." iopscience.iop.org/0004-637X

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Quantum_Conundrum
1.9 / 5 (9) Dec 21, 2010
Two of the stars they examined are known to be runaways that have been kicked out of their birth clusters.


Once again, my theory ends up being more correct than the previous prevailing theories.

on similar articles I have talked about alternate ways of a giant star forming, and either being ejected or else ejecting all other stars from a cluster, and of course, only to be mocked by the forum mafia as usual.

Big things form in all the same ways small things form. They can form one molecule at a time in cloud of dust and gas, or they can form in macro-scale or even mega-scale collisions. It's the same as asteroids, comets, moons, and planets.

No two objects in space form in a completely identical fashion because they all exist in environments that are slightly different: different density of nebula, different shape nebula, different composition nebula, etc.
SincerelyTwo
1.8 / 5 (5) Dec 21, 2010
Over a long enough period of time a number of stars and other massive objects in unstable orbits would eventually collide and collect due to gravity. After long enough time some given area around the collecting body of mass (for the most part stars) would have absorbed most of the stuff in the area around it.
Tuxford
1 / 5 (6) Dec 21, 2010
More and more difficult not to consider the astounding possibility: our observable universe is NOT a closed system. New matter nucleated (and energy generated) within massive bodies from an underlying, unobservable etheric realm, very slowly but in proportion to the local mass density. Objects grow over time. The most massive objects grow faster. An isolated big star is expected in this model. It should be relatively common.
Nik_2213
5 / 5 (4) Dec 21, 2010
Sorry, Tuxford but, unless you can persuade gravity to diminish to suit, orbits would not be stable on the time-scales we measure. For example, planets, asteroids and comets would have long-since spiralled into the Sun. Also, the Moon is receding from Earth due to tidal dissipation, currently about as fast as fingernails grow. Bouncing lasers off the Apollo and Russian retro-reflectors measures it to millimetres. If the two bodies were gaining mass, surely the Moon would have remained nearer the close, fast orbit where it formed after the Big Splat ??
Quantum_Conundrum
1.8 / 5 (6) Dec 21, 2010
Nik 2213:

Not that I support what Tuxford has said, but the Earth and Moon ARE each gaining mass, due to comet, meteor, and micro-meteor impacts, and always have been.

Even by the time you count all the stuff we've launched to distant planets or interstellar space, the earth has easily made a net gain in mass due to meteors of various sizes.

Many, many, many tons of dust-sized meteors hit the earth every day. That doesn't even count gravel and boulder sized meteors that also usually burn up completely in the atmosphere.
Tuxford
1 / 5 (5) Dec 22, 2010
While this is not my model, I understand that the mass accumulation rate in planet-size bodies is calculated to be so slow as to be near undetectable. Although the rate is higher inside stars, the mass-density ratio is such that 99% of new matter in our galaxy is generated inside Sagittarius A core star (the central 'black hole'). It is ejected periodically when instabilities arise. As a result, we see AGN's in the most massive cores, and Fermi bubbles in galaxies like ours.

Energy generated within planet-size bodies puts even gas giants on the stellar mass-luminosity relation.
kevinrtrs
1 / 5 (7) Dec 22, 2010
The most massive stars direct the evolution of their galaxies. Their winds and radiation shape interstellar gas and promote the birth of new stars.

The most vexing question still remains - just how did those first stars get formed?
Unless and until this question can be answered all the rest just remains a whole lot of hot gas speculation.
So far the big bang theory has been falsified at every turn, yet researchers still cling doggedly to it because there is nothing else. Take a look at the other bit of news the other day: Stars "form" much faster than expected. Another trying observation for the big bang.

Planetary issues: Hot jupiters abound - when they're not supposed to; planets orbiting in completely the opposite direction they're expected to. Planets in all kinds of planes other than the flat one expected. Planets in incrediblly impossible (70%)elliptical orbits. Huge planets in frustratingly impossible orbit swapping dances. The list is just going to get bigger.
tkjtkj
not rated yet Dec 22, 2010
Nik
... Also, the Moon is receding from Earth due to tidal dissipation, currently about as fast as fingernails grow.


I assume you mean dissipation of momentum .. Explain to me that if that is occurring, why is the moon not coming closer to earth?
Tuxford
1 / 5 (5) Dec 22, 2010

The most vexing question still remains - just how did those first stars get formed?
Unless and until this question can be answered all the rest just remains a whole lot of hot gas speculation.

This model of nucleation actually starts at the sub-atomic level, and includes nucleation in empty space, over a very very long time. This accounts for the intergalactic gas clouds, which eventually condense into lone stars, etc. In this model, the universe is far older than the big bang nonsense. How did those sub-billion year-old big galaxies form anyway???

Regarding planets, mother stars can become unstable and eject planetary forming material, forming gas giants closer to the parent star in some cases? The interior heat instability can also lead to stellar pulsation, in other cases. (Interior genic energy production — photon blue-shifting — is a function of local mass density.)
Skeptic_Heretic
4 / 5 (4) Dec 22, 2010
The most vexing question still remains - just how did those first stars get formed?
The fundamental forces.
Unless and until this question can be answered all the rest just remains a whole lot of hot gas speculation.
Answered
So far the big bang theory has been falsified at every turn
False
yet researchers still cling doggedly to it because there is nothing else.
Also false.
Take a look at the other bit of news the other day: Stars "form" much faster than expected. Another trying observation for the big bang.
Supports it, doesn't detract from it.
Planetary issues: Hot jupiters abound - when they're not supposed to
Says who?
planets orbiting in completely the opposite direction they're expected to.
And?
Planets in all kinds of planes other than the flat one expected.
And?
Planets in incrediblly impossible (70%)elliptical orbits.
So?
Huge planets in frustratingly impossible orbit swapping dances.
So? (TBC
Skeptic_Heretic
4.4 / 5 (7) Dec 22, 2010
Kevin,

Everytime you post I hope to get even a minor challenge that I really need to dig deep to answer. As it stands, all of these can be answered by a 7 year old. I know because I asked my nephew and he knew the answer to each.

If you would like, you can PM me your phone number and I'll have him call you.
taka
1 / 5 (3) Dec 22, 2010
The LaViolette theory Tuxford is defending here has beautiful particle part (http://www.starbu...on.pdf). But the aether part I do not like, the Einstein relativity is prettier. So I propagate even more crazy view that the space itself is generated. It is easy to see how it happens, usually they tell that mass spent a space and sits in the gravity well. But that is the two dimension picture, in three dimension you can see that there is just more space around mass then father away. So, mass is creating more space around itself. Now it is just logical conclusion that all space may be formed in this way. LaViolette use three vectors in his model, three independent vectors generate three dimensional space. And this space is sitting nowhere.
taka
1 / 5 (3) Dec 22, 2010
Nice Universe model comes out, stationary AND infinitely expanding (already infinite Universe can easily tolerate some expansion). Black hole singularity is impossible of course, before the matter can fall into singularity it will generate more space and it will fall infinitely. But Black holes are possible, they just have final size from outside and INFINITE size from inside, effectively they are lower level Universes. And our may be inside higher level one creating fractal structure.