Star formation may be halted by cold ionized hydrogen

**Star formation may be halted by cold ionised hydrogen
A composite image showing our Galaxy, the Milky Way, rising above the Engineering Development Array at the Murchison Radio-astronomy Observatory in Western Australia. The location of the centre of our Galaxy is highlighted alongside the ionized hydrogen (H+) signal detected from this region of sky. The white-blueish light shows the stars making up the Milky Way and the dark patches obscuring this light shows the cold gas that is interspersed between them. Credit: Engineering Development Array image courtesy of ICRAR. Milky Way image courtesy of Sandino Pusta

For the first time ionized hydrogen has been detected at the lowest frequency ever towards the center of our Galaxy. The findings originate from a cloud that is both very cold (around -230 degrees Celsius) and also ionized, something that has never been detected before. This discovery may help to explain why stars don't form as quickly as they theoretically could.

Dr. Raymond Oonk (ASTRON/Leiden Observatory/SURFsara) led this study which is published today in MNRAS. He said: "The possible existence of cold ionized gas had been hinted at in previous work, but this is the first time we clearly see it."

Ionization is an energetic process that strips electrons away from atoms. The atom will become electrically charged and can then be called an ion. This typically happens in gas that is very hot (10000 degrees Celsius) and where atoms can easily lose their electrons. It was therefore puzzling to discover the ionized hydrogen from very in this cloud. Normal sources, such as photons from massive stars, would not cause this. More exotic energy forms, such as created in supernova shockwaves and near black holes, are more likely to be responsible.

Dr. Oonk continues: "This discovery shows that the energy needed to ionize hydrogen atoms can penetrate deep into cold clouds. Such cold clouds are believed to be the fuel from which new stars are born. However, in our Galaxy we know that the stellar birth rate is very low, much lower than naively expected. Perhaps the energy observed here acts as a stabilizer for cold , thereby preventing them from collapsing on to themselves and forming new stars."

Credit: ICRAR

The observation was made with the Engineering Development Array (EDA), a prototype station of the Square Kilometre Array (SKA), the worlds' largest radio telescope. A/Prof. Randall Wayth (Curtin University/ICRAR) says: "This detection was made possible by the wide bandwidth of the EDA and the extremely radio quiet location of the Murchison Radio-astronomy Observatory. The low frequency portion of the Square Kilometre Array will be built at this location in the coming years, so this excellent result gives us a glimpse of what the SKA will be capable of once it's built."

The data reduction was led by Emma Alexander (University of Manchester) as part of her summer student internship at ASTRON: "It's a very exciting time to be coming into radio astronomy, and it was great to work on the first high resolution spectroscopic data from this SKA prototype station. The technologies that are being developed for the SKA, and the science results that come from them, will be a driving force for my generation of radio astronomers."


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More information: J. B. R. Oonk et al. Spectroscopy with the Engineering Development Array: cold H+ at 63 MHz towards the Galactic Centre. arXiv:1907.03127v1 [astro-ph.GA]: arxiv.org/abs/1907.03127
Citation: Star formation may be halted by cold ionized hydrogen (2019, July 10) retrieved 17 October 2019 from https://phys.org/news/2019-07-star-formation-halted-cold-ionized.html
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Jul 10, 2019
Cold plasma? That can't be real.... LOL!

Jul 10, 2019
What the hell is this astronomer calling ionized hydrogen in the first place?

The most common form of hydrogen in existence is H1, that is hydrogen with one proton & one electron in the orbital shell.

Ionization occurs when an electron is stripped from the electron shell, for the case of H1 that leaves only a proton remaining which is a sub-atomic particle. I've never heard of a proton referred to as "ionized hydrogen". We already know stars cannot be created from protons alone, this astronomer needs to take a first semester college chemistry course.

RNP
Jul 10, 2019
@Benni
What the hell is this astronomer calling ionized hydrogen in the first place?

I've never heard of a proton referred to as "ionized hydrogen".

...this astronomer needs to take a first semester college chemistry course.


All the above just shows how clueless you are. Just go and Google "ionized hydrogen"... it is all there in the literature if you had a real desire to understand it.

Simply put, ionized hydrogen is a mixture of free protons and their disassociated electrons (and more often than not, some neutral hydrogen as well).

Why do you not even TRY to understand things before you comment on them? Why do you insist on making a fool of yourself?

Jul 10, 2019
Cold plasma? That can't be real.... LOL!
Correct. "cold plasma" appears nowhere in the text. "plasma" appears nowhere in the text. The informal term "cold plasma" is applied to a number of phenomena, none of which match the description of a -230 C gas.

Jul 10, 2019
I've never heard of a proton referred to as "ionized hydrogen". We already know stars cannot be created from protons alone, this astronomer needs to take a first semester college chemistry course.
Unfortunately, Matt has left out some salient items of the original: "The stacked Hnα detection at 63 MHz is the lowest frequency detection made for hydrogen RRLs and shows that a cold (partially) ionized medium".

Firstly, this is not a uniformly ionized gas. It's (evidently) cold molecular hydrogen with some H+ ions dissociated from their electrons. But the electrons are still there.
Secondly, while the protons themselves are described as 'cold', the proposed mechanism of creation of this (partially) ionized gas would leave a conservation of energy conundrum; therefore the electron-temperature might be very high. This seeming paradox occurs in mercury-vapour lamps where the heavy ions themselves are cool, ~ room temperature, but the electrons are at some 2.0 x 10^4 K.

Jul 10, 2019
Simply put, ionized hydrogen is a mixture of free protons and their disassociated electrons (and more often than not, some neutral hydrogen as well).
.........bullshit with "Simply put", I've been working in the field of nuclear physics my entire engineering career & we NEVER refer to a proton as ionized hydrogen, it's a sub-atomic particle, period.

I can design a nuclear reactor system without ANY assistance from Google, but YOU can't even find the correct definition of a proton from a search engine site because you don't even know what you're looking for in the first place.

RNP
Jul 10, 2019
Simply put, ionized hydrogen is a mixture of free protons and their disassociated electrons (and more often than not, some neutral hydrogen as well).
.........bullshit with "Simply put", I've been working in the field of nuclear physics my entire engineering career & we NEVER refer to a proton as ionized hydrogen, it's a sub-atomic particle, period.

I can design a nuclear reactor system without ANY assistance from Google, but YOU can't even find the correct definition of a proton from a search engine site because you don't even know what you're looking for in the first place.


No Benni. You are a joke (and a liar). You have never been educated in science, as is blatantly clear in every post you make. Your only value (and the only reason that I still read your posts) is your comedy value. Still, sometimes, your stupidity angers me,


Jul 10, 2019
Nature of Molecular Hydrogen
Molecular hydrogen is rarely looked for in space. In most papers in astrophysics, the word hydrogen is mentioned without distinguishing whether it is atomic or molecular. Yet it is a well-known fact of basic chemistry that atomic hydrogen is extremely unstable, and that it reacts violently to produce molecular hydrogen, which is extremely stable. Given a bottle of pure atomic hydrogen, one would expect an immediate energetic explosion, producing molecular hydrogen at a very high temperature.
Atomic hydrogen (H), composed of a single proton and electron, is the simplest existing stable atom. Because of the spin structure of the particle, it is easily detectable using a high frequency radio signal at 21-cm wavelength. Atomic hydrogen in galaxies and in intergalactic space can be detected very easily, because the atomic hydrogen can change its spin (which changes its energy).

Jul 10, 2019
Electromagnetic radiation is emitted at the wavelength of 21 cm, or an absorption line is observed (in the background radiation) at that wavelength. However, when two atoms of atomic hydrogen combine, forming molecular hydrogen (H2), their spins are
coupled and completely cancel each other. The radio-frequency spectral line at 21 cm no longer exists, and the molecular hydrogen becomes totally invisible at that wavelength.
The possible vibrational and rotational states for the two hydrogen nuclei in the diatomic hydrogen molecule are well known (cf. Herzberg 1950). However, the only two electrons are so tightly coupled, that they form a pair in which the electric field and the spin of the electrons are completely cancelled.

Jul 10, 2019
Molecular hydrogen possesses no permanent dipole. Such a perfect coupling is unusual among diatomic molecules. For example, in the cases of nitrogen and oxygen, there are seven and eight electrons per atom, so that when combined, it is not possible to fulfill such a perfect coupling of spins (with zero permanent dipole) for all seven or eight pairs of electrons.
When light passes through normal molecular gases, such as oxygen, nitrogen, and others, radiation excites the resulting electric dipole in the molecule, and some energy is scattered or absorbed. However, in the case of molecular hydrogen, there is no dipole moment, so that no radiation can be absorbed or emitted.

Jul 10, 2019
However, it is well known that atomic hydrogen in space was certainly naturally transformed into H2. Over billions of years, dust, three-body interactions, and even
photon emission have produced H2. Once molecular hydrogen is formed, it is so stable that it has little probability of dissociation. It cannot be argued that H2 does not exist in
space because it could be ionized or dissociated by ultraviolet radiation. If there were enough ultraviolet radiation to ionize H2, that same radiation would also ionize atomic
hydrogen. This is not the case, because non-ionized atomic hydrogen is observed, even though it requires less energy to ionize the atomic than the molecular form of hydrogen.

Jul 10, 2019
Published in 21st CENTURY Science & Technology, Spring 2000, Pages 5 - 7
Discovery of H2, in Space
Explains Dark Matter and Redshift
by Paul Marmet

Jul 10, 2019
Correct. "cold plasma" appears nowhere in the text. "plasma" appears nowhere in the text.


So, cold ionized hydrogen is cold plasma, literally just symantics.
Plasma is by definition ionized matter, it wouldn't be plasma if it weren't ( at least 1% ionized making it conductive).

Jul 10, 2019
Secondly, while the protons themselves are described as 'cold', the proposed mechanism of creation of this (partially) ionized gas would leave a conservation of energy conundrum; therefore the electron-temperature might be very high
-which would make it this;

"Nonthermal plasmas on the other hand are non-equilibrium ionized gases, with two temperatures: ions and neutrals stay at a low temperature (sometimes room temperature), whereas electrons are much hotter."

-Correct?

"Impermeable plasma is a type of thermal plasma which acts like an impermeable solid with respect to gas or cold plasma and can be physically pushed. Interaction of cold gas and thermal plasma was briefly studied by a group led by Hannes Alfvén in 1960s"

... hey I've heard of him-

-Much more useful to quote than ad lib.

Jul 10, 2019
So, cold ionized hydrogen is cold plasma, literally just symantics
Research of valid sources would tell you it's literally more complicated than this.

Try google.

Jul 10, 2019
I've never heard of a proton referred to as "ionized hydrogen".


Now you have. Congrats, you're learning!

Jul 10, 2019
Cold plasma? That can't be real.... LOL!
Correct. "cold plasma" appears nowhere in the text. "plasma" appears nowhere in the text. The informal term "cold plasma" is applied to a number of phenomena, none of which match the description of a -230 C gas.

LOL, ionized gas is the misleading terminology used by plasma ignoramuses to obfuscate the need to rely on modern plasma physics in favor of their simplistic ideal gas guesswork. It is just another example of the ignorance of plasmas by astrophysicists. And although it should just be a matter of semantics it is not due to the errant application of irrelevant gas physics.

Jul 10, 2019
MH sez:

However, it is well known that atomic hydrogen in space was certainly naturally transformed into H2. Over billions of years, dust, three-body interactions, and even
photon emission have produced H2. Once molecular hydrogen is formed, it is so stable that it has little probability of dissociation. It cannot be argued that H2 does not exist in
space because it could be ionized or dissociated by ultraviolet radiation. If there were enough ultraviolet radiation to ionize H2, that same radiation would also ionize atomic
hydrogen. This is not the case, because non-ionized atomic hydrogen is observed, even though it requires less energy to ionize the atomic than the molecular form of hydrogen.
.......the article doesn't state anything about H2 Molecular Hydrogen as being the ionized hydrogen under discussion.

Jul 10, 2019
Star formation is one of the least comprehended phenomenon in astrophysics. Is there a general theory of star formation? No, there is not. There is a number of models based on computer simulations which include supersonic hydrodynamics with non-ideal MHD turbulence influenced by gravity. They include the line and continuum radiative processes of the energy transfer; a number of chemical processes with dissociation, recombination and ionization, with uncertain nomenclature of atoms and molecules, unknown magnetic fields and formation and destruction of dust particles. In addition there is macrophysics that is an environment in the molecular clouds, clumps and cores; inclusion in the multiple systems, collisions among stellar systems; jets and outflows; radiation pressure.
https://www.acade...ormation

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