Large water reservoirs at the dawn of stellar birth

Oct 09, 2012
Herschel's infrared view of part of the Taurus Molecular Cloud, within which the bright, cold pre-stellar cloud L1544 can be seen at the lower left. It is surrounded by many other clouds of gas and dust of varying density. The Taurus Molecular Cloud is about 450 light-years from Earth and is the nearest large region of star formation. The image covers a field of view of approximately 1 x 2 arcminutes. Credit: ESA/Herschel/SPIRE

(Phys.org)—ESA's Herschel space observatory has discovered enough water vapour to fill Earth's oceans more than 2000 times over, in a gas and dust cloud that is on the verge of collapsing into a new Sun-like star.

Stars form within cold, dark clouds of gas and dust – 'pre-stellar cores' – that contain all the ingredients to make solar systems like our own.

Water, essential to life on Earth, has previously been detected outside of our Solar System as gas and ice coated onto tiny dust grains near sites of active star formation, and in proto-planetary discs capable of forming alien planetary systems.

The new Herschel observations of a cold pre- in the constellation of Taurus known as Lynds 1544 are the first detection of water vapour in a molecular cloud on the verge of star formation.

More than 2000 Earth oceans-worth of water vapour were detected, liberated from icy dust grains by high-energy cosmic rays passing through the cloud.

Close-up of L1544 with the water spectrum seen by Herschel, taken from the centre of the pre-stellar core. The peak of the graph shows an excess in brightness, or emission, while the trough shows a deficit, or absorption. These characteristics are used to indicate the density and motions of the water molecules within the cloud. Emission arises from molecules that are approaching the centre where the new star will form, from the back of the cloud from Herschel’s viewpoint. The amount of emission indicates that these molecules are moving within the densest part of the core, which spans about 1000 Astronomical Units. The absorption signature is due to water molecules in front of the cloud flowing away from the observer towards the centre. These water molecules are in less dense regions much further away from the centre. Together, the emission and absorption signatures indicate that the cloud is undergoing gravitational contraction, that is, it is collapsing to form a new star. Herschel detected enough water vapour in L1544 to fill Earth’s oceans more than 2000 times over. Credits: ESA/Herschel/SPIRE/HIFI/Caselli et al.

"To produce that amount of vapour, there must be a lot of water ice in the cloud, more than three million frozen Earth oceans' worth," says Paola Caselli from the University of Leeds, UK, lead author of the paper reporting the results in .

"Before our observations, the understanding was that all the water was frozen onto dust grains because it was too cold to be in the gas phase and so we could not measure it.

"Now we will need to review our understanding of the chemical processes in this dense region and, in particular, the importance of cosmic rays to maintain some amount of water vapour."

The observations also revealed that the water molecules are flowing towards the heart of the cloud where a new star will probably form, indicating that has just started.

"There is absolutely no sign of stars in this dark cloud today, but by looking at the , we can see evidence of motion inside the region that can be understood as collapse of the whole cloud towards the centre," says Dr Caselli.

"There is enough material to form a star at least as massive as our Sun, which means it could also be forming a planetary system, possibly one like ours."

Some of the water vapour detected in L1544 will go into forming the star, but the rest will be incorporated into the surrounding disc, providing a rich water reservoir to feed potential new planets.

"Thanks to Herschel, we can now follow the 'water trail' from a in the interstellar medium, through the star formation process, to a planet like Earth where water is a crucial ingredient for life," says ESA's Herschel project scientist, Göran Pilbratt.

Explore further: Magnetar discovered close to supernova remnant Kesteven 79

More information: "First detection of water vapour in a pre-stellar core," by P. Caselli et al. has been accepted for publication in Astrophysical Journal Letters.

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cantdrive85
1 / 5 (10) Oct 09, 2012
"Now we will need to review our understanding of the chemical processes in this dense region and, in particular, the importance of cosmic rays to maintain some amount of water vapour."

What they need is a better understanding of plasma, this will go much farther for their understanding than chemistry or gas hydrodynamics.
barakn
5 / 5 (8) Oct 09, 2012
Since they didn't mention chemistry or gas hydrodynamics, but rather cosmic rays which have the potential to ionize atoms and molecules, your notion that they aren't considering plasma is entirely misguided.
cantdrive85
1 / 5 (10) Oct 09, 2012
A better understanding would let them in on the secret that it is already plasma, being that the ONLY places in the Universe where matter exists in a different state (than plasma) is on rocky bodies with atmospheres. Many have a misguided understanding of matter in our Universe, the primary state is plasma, unlike here on Earth (rocky body w/ atmosphere) where the other three forms of matter dominate.
barakn
5 / 5 (7) Oct 09, 2012
You couldn't properly read a news release and you think they're misguided?
cantdrive85
1 / 5 (9) Oct 09, 2012
I read the article talking about "gas" and "vapor" in this molecular cloud, but I'm also aware of research that showed these molecular clouds are indeed, plasma clouds. The properties and characteristics of which, will be directed by the EM force. The movement they are detecting is due to the electric currents flowing through the dusty plasma.
Q-Star
2 / 5 (4) Oct 09, 2012
Plasma, plasma, plasma,,,, EVERYTHING is plasma. There is nothing but plasma.
cantdrive85
1 / 5 (9) Oct 09, 2012
Plasma, plasma, plasma,,,, EVERYTHING is plasma. There is nothing but plasma.

You're finally catching on, 99.9999% of the visible Universe is plasma, there is little need to discuss much else, especially when it pertains to astronomy.
Torbjorn_Larsson_OM
5 / 5 (7) Oct 10, 2012
EU/PC believers shouldn't comment on science. It is hilarious to see.

Even more when they can't read either press release or ironic comments with any signs of understanding either. And these ignorants presume to tell others how anything works. Hilarious times.
Shinobiwan Kenobi
3 / 5 (4) Oct 10, 2012
Derp derpa, science is revising what it has previously recorded because of new observations?! Surely this must mean we should discard systems already in place in favor of another theory with more nebulous parameters in light of more recent discoveries rather than refine the existing model!
thingumbobesquire
1 / 5 (7) Oct 10, 2012
And God made the firmament, and divided the waters which were under the firmament from the waters which were above the firmament: and it was so.
rubberman
2.3 / 5 (3) Oct 10, 2012
EU/PC believers shouldn't comment on science. It is hilarious to see.

Even more when they can't read either press release or ironic comments with any signs of understanding either. And these ignorants presume to tell others how anything works. Hilarious times.


Lidia van Driel-Gesztelyi said: "The Sun's magnetic field and atmosphere are very different to what we experience at the Earth. The Sun's atmosphere is electrically charged which means that the particles are trapped by the magnetic field – the magnetic field acts as a tube along which the gases flow. But the magnetic fields themselves are dynamic. They can stretch out like elastic bands and also snap apart and then connect up with neighbouring magnetic fields."

Tor - Lidia is the team leader researching solar wind (See Physorg article). She IS a scientist, yet the final sentence in the above quote is also pretty hilarious. Astrophysicists apparently can be equally daft when commenting on plasma phenomena.
rubberman
3.7 / 5 (3) Oct 10, 2012
CD85 - If it is a molecule or dust, it isn't plasma. Hence the post from Tor. Dust would be considered a "rocky body".
GSwift7
4.2 / 5 (9) Oct 10, 2012
I read the article talking about "gas" and "vapor" in this molecular cloud, but I'm also aware of research that showed these molecular clouds are indeed, plasma clouds.


You need to do a little bit of reading. In the case of a planetary nebula, like the one above, there are gases and dust. Some of those gases and dust are ionized, and are therfore a plasma. So, you are correct that there should be plasma there, but not the kind you are thinking of. Try reading the following wiki pages on "dusty plasmas" and "accretion disks" for starters:

http://en.wikiped...y_plasma
http://en.wikiped...ion_disc

In the case above, there is certainly gas plasma present. The molecules of water they mention above are probably ionized as well (see the dirty plasma page). The spiral of material falling in to form the above star should generate a magnetic field as well. This is all part of the standard star formation model.
GSwift7
4.3 / 5 (8) Oct 10, 2012
Continued:

Note that for particles of micrometer size or larger, gravity will overwhelm the electromagnetic forces in the plasma of the protoplanetary disk. It is not a choice between plasma and gravity, but rather a complex system with both types of interaction. I will again stress that this is NOT something that supports the electric universe theories. This IS part of the conventional, standard accretion model of solar system formation. The standard model of star/planet formation does include the interaction of charged particles in the plasma of the protoplanetary disk. There would not be any net current flow in the system, but there are charged particles and magnetic fields generated by the movement of the charged particles caused by gravity and the laws of conservation of angular momentum. Also note that we are not nessessarily talking about a hot plasma here. These will be mostly below 100 kelvin until the star actually starts to form.
rubberman
2.3 / 5 (3) Oct 10, 2012
CD85 - If it is a molecule or dust, it isn't plasma. Hence the post from Tor. Dust would be considered a "rocky body".


This explains it better:
http://www.madsci...h.r.html

Also apologies to Tor, Lidia's personal page has her listing her credentials, she isn't an astrophysicist. Although she appears to have enough scientific background to know better than to make that last statement regarding the breaking of magnetic field lines.
GSwift7
3 / 5 (4) Oct 10, 2012
CD85 - If it is a molecule or dust, it isn't plasma. Hence the post from Tor. Dust would be considered a "rocky body".


That's what I was thinking too, but that's kinda a grey area strictly due to terminology. In the case of a dusty plasma, the water molecules, and even larger objects could be considered as part of the plasma. If the charge is great enough and the mass of the objects is small enough, then their motions may even be affected by the magnetic fields of the plasma. That's not Electric Universe hokus-pokus sci-fi, that's just standard stuff. The EU crap only falls apart at scales larger than a single solar system. At solar scales, as above, the electric properties are in line with conventional theory. The gas and molecules falling into the proto-star formation region should generate a magnetic field and charge. My wiki links above explain it better than I can. That should impart charge to the water molecules and dust as well as atoms. It wouldn't be much though.
cantdrive85
1 / 5 (6) Oct 10, 2012
CD85 - If it is a molecule or dust, it isn't plasma. Hence the post from Tor. Dust would be considered a "rocky body".


It's been shown here; http://phys.org/n...ry.html, that dust in plasma becomes a plasma itself.

These articles describe quite clearly that molecular clouds are in fact plasma.
http://iopscience...20/2/706
http://plasmauniv...007b.pdf
Fleetfoot
5 / 5 (6) Oct 10, 2012
Also note that we are not nessessarily talking about a hot plasma here. These will be mostly below 100 kelvin until the star actually starts to form.


The pre-print is here:

http://arxiv.org/abs/1208.5998

The measurements have been made at 557GHz which is a transition line for ortho-H2O. The water in vapour phase is photo-desorbed from the grains but not ionised. Temperatures in the cloud range from 6K at 300AU to a peak of 11K at 7,000AU and falling to 8K at 15,000AU.

The picture is one of small dust grains covered with a layer of ice and a tiny amount of sublimated water vapour.

Ionisation of the water is also considered in the paper and occurs outside the molecular cloud where the thinner material is exposed to cosmic rays causing a rapid rise in temperature beyond 20,000AU. Inside that, the cloud is dense enough to be dark hence it is not ionised.

Plasma is a state of matter. In this case the H2O is in the solid state with a little gas, it is not a plasma.
rubberman
1 / 5 (1) Oct 11, 2012
CD85 - If it is a molecule or dust, it isn't plasma. Hence the post from Tor. Dust would be considered a "rocky body".


It's been shown here; http://phys.org/n...ry.html,


LOL, that is the article that actually peaked my interest in plasma phenomena. However it is also the reason i made that statement with regards to molecules and dust. After reading it I began researching plasma because my understanding prior to that article was that all stellar/interstellar plasma was atomic, not molecular.

http://physics.ap...v22/st17

But I agree with "dusty plasma" as proposed in that article, as well as GS7 wiki page because it (the dust) behaves as though it is part of the plasma.
GSwift7
3.3 / 5 (4) Oct 11, 2012
Plasma is a state of matter. In this case the H2O is in the solid state with a little gas, it is not a plasma.


I hate to say it, but cantdrive's last post before this is correct. It's a terminology issue. There's more than one meaning for the term "plasma".

Yes, there is a state of matter that is called plasma, where individual atoms have so much energy that they cannot bond with other atoms and their electrons become free.

There is also a type of body in astronomy called a plasma that refers to a cloud of charged particles. They use the term plasma to describe them because they move as a plasma does in response to magnetic fields. Examples of such are the accretion disks around black holes, quasars, newly formed stars, etc. In the extreme case of an active black hole, the magnetic fields are so strong that large objects can accquire a chage and act as a part of the body called the plasma. It moves as a plasma, even though it is not entirely plasma.
GSwift7
3.6 / 5 (5) Oct 11, 2012
But I agree with "dusty plasma" as proposed in that article, as well as GS7 wiki page because it (the dust) behaves as though it is part of the plasma


lol, you posted while I was writing my response. Yes, they refer to the entire body of material as "a plasma", even though it has stuff in it that isn't in the plasma state of matter. They name it this way because the net motions of the material behave as a plasma would, and it forms structures governed by electromagnetism as a plasma does, as well as gravity and newtonian laws of motion like conservation of momentum etc.

The electric universe cosmology theory attempts to take these properties to intergalactic scales, though there's no eveidence that they apply beyond the scale of a single solar system.
Fleetfoot
5 / 5 (7) Oct 11, 2012
There's more than one meaning for the term "plasma".

Yes, there is a state of matter that is called plasma, where individual atoms have so much energy that they cannot bond with other atoms and their electrons become free.

There is also a type of body in astronomy called a plasma that refers to a cloud of charged particles. ... It moves as a plasma, even though it is not entirely plasma.


I understand that but please read the paper, especially regarding the bottom panel of Figure 3:

http://arxiv.org/abs/1208.5998

They are quite clear in the text that the water is ionised outside the cloud, you can see that effect clearly on the "T" curve. They explain that the interstellar radiation is absorbed by that outer layer making the interior dark and not ionised at all. The water molecules are "desorbed", not ionised. The cloud isn't behaving like a plasma but as dust in vapour.
GSwift7
3.3 / 5 (4) Oct 11, 2012
They explain that the interstellar radiation is absorbed by that outer layer making the interior dark and not ionised at all. The water molecules are "desorbed", not ionised. The cloud isn't behaving like a plasma but as dust in vapour.


Then it isn't very far along the star formation process. It should self-ionize later in the process, due to conservation of angular momentum as it collapses. In the above story you can already see the spike in particle velocity at the center. That will eventually reach the electron dissociation energy threshold as I understand it.
cantdrive85
1 / 5 (7) Oct 11, 2012
They are claiming the matter to be "desorbed", but that is due to an incomplete understanding of the matter they are observing. They are merely applying the properties of a gas where the properties of plasma MUST be considered. The flow of particles into the center of the cloud is evidence of currents flowing and the magnetic fields that are present in these structures further confirms this, and we know that currents must flow in a closed circuit. Even if it is partially ionized by .00001%, this is adequate enough for EM forces to dominate the behavior of the cloud.
GSwift7
3 / 5 (4) Oct 11, 2012
They are quite clear in the text that the water is ionised outside the cloud, you can see that effect clearly on the "T" curve. They explain that the interstellar radiation is absorbed by that outer layer making the interior dark and not ionised at all


They kinda skipped over it really quickly, but they mention that the center of the cloud is visually extinct, meaning they can't get a spectrum from there. The composition of the center is based on their model and some assumptions. They are deliberately ignoring the gas phase formation of water at the center. Here's the quote:

Here we briefly mention that the formation of water is assumed to happen on dust grain surfaces by the reaction of OH and H. Gas phase routes to the formation of water in cold gas are not included
GSwift7
4.3 / 5 (6) Oct 11, 2012
The flow of particles into the center of the cloud is evidence of currents flowing and the magnetic fields that are present in these structures further confirms this, and we know that currents must flow in a closed circuit


Sorry, that's not true. This type of plasma does not show current flow. There are free electrons, but the net motion of them is random, non-directional. The particle motion is gravitational and conservation of angular momentum. It's a PERFECT fit to the mathematical models. There's no closed circuit here. I don't know where you are getting that idea.
cantdrive85
1 / 5 (7) Oct 11, 2012
Sorry, that's not true. This type of plasma does not show current flow. There are free electrons, but the net motion of them is random, non-directional. The particle motion is gravitational and conservation of angular momentum. It's a PERFECT fit to the mathematical models. There's no closed circuit here. I don't know where you are getting that idea.


If it is a plasma, which it has been shown to be, it will adhere to the properties of EM. All gas laws and mechanical interactions can be discarded, they have no appreciable effect on electrified plasma.

They go on to mention; "The observed extra-emission at low velocities suggests the presence of higher velocity motions, probably due to larger infall velocities within the central 1000AU than predicted by our models (Fig. 3)."

This discrepency, that the infalling matter is accelerating, is also explained by the electrical nature of the plasma. Only electric fields can accelerate matter in such a manner, gravity will be constant.
rubberman
1.5 / 5 (2) Oct 11, 2012
"The particle motion is gravitational and conservation of angular momentum. "

In a proto planetary disk, the EM fields void angular momentum which is what enables the collapse, they must be present.

http://www.schola...c_fields

"This discrepency, that the infalling matter is accelerating, is also explained by the electrical nature of the plasma. Only electric fields can accelerate matter in such a manner, gravity will be constant."

Only if mass is a constant, as the mass of the proto star increases, so does the gravitational pull towards the center. It takes both forces to generate star formation....EVERYONE WINS!
Fleetfoot
5 / 5 (5) Oct 11, 2012
Sorry, that's not true. This type of plasma does not show current flow. There are free electrons, but the net motion of them is random, non-directional. The particle motion is gravitational and conservation of angular momentum. It's a PERFECT fit to the mathematical models. There's no closed circuit here. I don't know where you are getting that idea.


If it is a plasma, which it has been shown to be, ...


Nope. Other clouds may have been but not this one, it is almost entirely just specks of dust embedded in solid ice, it is not plasma. Beyond about 20,000AU the far UV photons photodissociate the water and create plasma but inside that it is too dark. The effect is obvious in the graphs.

This discrepency, that the infalling matter is accelerating, is also explained by the electrical nature of the plasma.


Nope, plasma would not cause radial acceleration towards the centre, it would produce spiral motion around the magnetic field as you have said yourself before.
Fleetfoot
5 / 5 (5) Oct 11, 2012
They explain that the interstellar radiation is absorbed by that outer layer making the interior dark and not ionised at all


They kinda skipped over it really quickly, but they mention that the center of the cloud is visually extinct, meaning they can't get a spectrum from there.


Visually yes, so UV photons can't reach it, but their observations were at 557GHz where it is transparent.

They are deliberately ignoring the gas phase formation of water at the center. Here's the quote: ...


Here's an earlier one which explains why they do that:

Such a large amount of water cannot be produced via gas-phase routes and then deposited on top of dust grains, as gas-phase chemistry can only account for about one thousandth of the ice abundance (Lee et al. 1996). Thus, it is now well-established that water ice is formed on the surface of dust particles via hydrogenation of atomic and molecular oxygen (Ioppolo et al. 2008).


The dust acts as a catalyst.
GSwift7
1 / 5 (2) Oct 12, 2012
Visually yes, so UV photons can't reach it, but their observations were at 557GHz where it is transparent


You do not understand the term 'visually extinct'. This term does not only apply to the human visible spectrum. The term applies to any frequency. See the following link:

http://en.wikiped...tronomy)

In the story above, they had to assume what the inner 1000 AU of the cloud looks like because they could not get any useful observations of that region due to visual extinction. The wavelengths that show the presence of water are totally blocked in that region. It even says this in the paper. I don't know why you are arguing with me. I just read the paper, and told you what they said. It's not my fault that you don't understand the terms, and are too lazy to look them up, but saying that I'm wrong when you obviously don't have a clue is just hillarious.