Abyss of organics new complex alcohol discovered in space

(ORDO NEWS) — Astronomers have found alcohol isopropanol in a cloud of cosmic gas. It is one of the most complex organic compounds ever found in interstellar space. In honor of this discovery.

Astronomers have detected isopropanol in the Sagittarius B2 (Sgr B2) interstellar cloud using the best-in-class ALMA radio telescope.

Along with its twin brother propanol, it is the most complex alcohol and generally one of the most complex chemical compounds found in interstellar matter.

The discovery will help scientists figure out where organic matter comes from in space, which may serve as a breeding ground for the emergence of life.

Propanol (propyl alcohol) is an alcohol with the chemical formula C 3 H 7 OH. Propanol is found in perfumes, skin disinfectants, and so on (just in case: you should never drink it).

Abyss of organics new complex alcohol discovered in space 2
Structural formula of propanol

This is only the third alcohol discovered in space. The first were methanol (CH 3 OH) and ethanol (C 2 H 5 OH). It is easy to see that the propanol molecule is more complex: it has 12 atoms. Nine-atomic ethanol is left behind, but we love it not for that.

In general, today molecules of 276 substances, organic or not, have been found in the interstellar medium (below we will talk about how astronomers detect chemical compounds in space).

Only 19 of them consist of 12 or more atoms. Apart from fullerenes C 60 and C 70 , the most complex “interstellar” compound is cyanonaphthalene C 10 H 7 CN. Twenty atoms in a molecule is not much more than twelve.

Thus, propanol is not only the most complex alcohol, but in general one of the most complex substances ever discovered in interstellar space.

Stop, the attentive reader will exclaim, what does propanol have to do with it when we talked about isopropanol? Even though it’s almost the same.

Isopropanol, also known as 2-propanol, differs from propanol only in the arrangement of atoms in the molecule. The OH group in it is attached not to the terminal, but to the middle carbon atom.

Abyss of organics new complex alcohol discovered in space 3
Structural formula of isopropanol

Earlier, astronomers working with ALMA detected propanol in the same Sagittarius B2 cloud. Now its twin isopropanol has been added to it.

This discovery was not easy to make. ALMA is the most sensitive instrument in the world in its range of radio waves, and if its sensitivity were at least half that, astronomers would not see a new connection.

Now scientists have to carefully measure whether there is more propanol or isopropanol in the interstellar cloud, and how much. Why is it important?

Because these compounds are very similar in molecular structure, and therefore, in their chemical and physical properties.

There are very few processes that prefer one of these substances to another. And this is a very strict limitation for any theory that explains how organic matter is formed in cold clouds of interstellar matter.

And scientists love strict observational constraints. They allow you to discard incorrect models and understand what is really happening.

Substratum of life

By the way, what is organic? Once “organic” meant “coming from living nature.” Natural scientists called so substances that seemed impossible to obtain without the participation of living organisms.

True, the first breach in this idea was made as early as the beginning of the 19th century, and today it has been completely scrapped.

But the adjective “organic” stuck to certain compounds. So today, textbook writers have to wrestle with how to define the term to include methane and urea, but not water or carbon dioxide, among other things.

We will not chase after the strictness of wording. Just note that the basis of almost any organic molecule is a chain of carbon atoms. On the sides, atoms of other elements, most often hydrogen, are attached to these carbon units.

Sometimes these chains contain only a few atoms. Then you get the simplest organics like the already mentioned ethanol and propanol. But carbon atoms can also line up in chains of enormous length.

For example, in a polyethylene molecule several thousand atoms are lined up in a row. In general, bizarre polyatomic molecules are the calling card of organic chemistry.

But polyethylene also pales in comparison with human DNA, in the molecule of which there are billions of carbon units.

However, life is the most complex chemical phenomenon that we know. It is not surprising that it requires the most complex substances.

So “organic” no longer means “biological”, but “biological” is almost always “organic”. Proteins, fats, carbohydrates, DNA and more are organic compounds. Without complex organic matter, life as we know it is impossible. That is why there is so much interest in organics in space.

When organics are older than stars

Organic matter is not uncommon in the solar system. They have been found on planets and moons, comets and asteroids, on icy bodies in the Kuiper Belt, and in meteorites. But when did this organic originate? After the formation of the planets?

Or earlier, in the protoplanetary disk surrounding the newborn Sun? Or maybe it is older than our star and we inherited it from a protostellar cloud?

The correct answer to this question depends on what kind of organic matter. Some organic matter is emerging in the solar system right now. For example, it is assumed that the orange haze in Titan’s atmosphere is composed of organic matter formed under the influence of solar ultraviolet radiation.

On the other hand, there was also organic matter in the protoplanetary disk. It is rich in some meteorites that formed before the planets.

But we have little information about the composition of protosolar matter. True, its microscopic inclusions (presolar grains) are occasionally found in meteorites.

But this is literally crumbs of the necessary information. It is not so easy to find traces of events that took place 5 billion years ago!

Fortunately, there are enough places in the Galaxy where stars are being born right now. Among these “maternity hospitals” and Sagittarius B2.

Space is in no hurry

Interstellar space is not an absolute void. The total mass of matter scattered over it is not inferior to the total mass of stars. And in the end, it is from him that the luminaries are born, so we can’t discount him in any way.

But there it is not so easy to meet molecules, and even more so chemical reactions. If you poke your finger at a random point in the Milky Way, the local hydrogen is likely to be plasma or single atoms, but not H 2 molecules .

And yet there are clouds of molecular hydrogen in the Galaxy. The mass of such a cloud can be measured in millions of suns. These clouds are huge and heterogeneous.

They have clumps, where the density of matter is sufficient for the birth of stars. This is the chemical cauldron of the universe. But if it seems to you that it boils and boils, you are mistaken.

For starters, there is a very low concentration of gas (we can recognize it from the radio waves emitted by hydrogen molecules).

The average distance between adjacent molecules is measured in meters. Meters! By earthly standards, this is simply a vacuum. The chemist will not be pleased with the temperature, which is only a few degrees above absolute zero.

Finally, the composition of this matter has changed little since the time when there were no stars in the Universe yet. It is still almost entirely composed of the simplest elements: 77% hydrogen and 21% helium. The rest of the periodic table accounts for less than 2 percent. What and with what to react here?

And yet the cloud is scattered with microscopic solid dust particles inherited from a previous generation of stars. Reactions take place on their surface. Time is the resource that the interstellar chemical cauldron has in abundance.

Processes that take seconds on Earth take hundreds of thousands and millions of years. Reactions facilitate cosmic rays. They strip electrons from some atoms and turn them into ions, which are much more active than neutral atoms.

It is true that some of the molecules formed would throw the terrestrial chemist into confusion. This is, for example, an OH molecule (not H 2 O).

“Two such molecules form a water molecule as soon as they meet!” exclaims the chemist. “They won’t meet,” the astronomer will smile. However, there are quite familiar substances in interstellar clouds, such as formaldehyde and acetic acid.

Dark forest organics

How do astronomers detect certain substances in distant interstellar clouds? The fact is that molecules emit or absorb radiation at strictly defined frequencies (in spectral lines, as experts say). Each substance has its own set of spectral lines, individual, like fingerprints.

Of course, the spectral trace of a substance becomes distinguishable from the Earth only when there is a sufficiently large amount of this substance in the field of view of the telescope. This is not about concentration (it is very low), but about the total mass.

However, a molecule of ten atoms can have thousands of lines, and not all of them are known to experimenters.

And very close to them are lines of other molecules, and all this merges into an impenetrable forest. So detecting a spectral line is not as difficult as identifying it. Therefore, we still do not have any complete list of the ingredients of the interstellar cocktail.

But gradually more advanced telescopes come into operation. Yes, and laboratories accumulate data on the spectral lines of various substances.

Astronomers of the 21st century have a very interesting task ahead of them: a complete census of interstellar organics. This will help to understand what role it plays in the emergence of life on planets.


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